Galliform exclusion from the Migratory Bird Treaty Act has produced an alternate conservation path, but no evidence for differences in population status

Abstract

The Migratory Bird Treaty Act (MBTA) is critical to avian conservation in the United States, both through its protection of migratory birds and as a catalyst for a century of coordinated avian conservation. While more than 1,000 species are protected by MBTA, of extant bird species native to the continental U.S., only 20 species belonging to the order Galliformes are explicitly excluded. Management of galliforms has occurred largely without direct federal oversight, placing this group on a fundamentally different conservation path during the century following MBTA passage. In this paper, we review the historical context and biological justification for exclusion of galliforms from MBTA and synthesize how their present-day conservation differs from that of migratory birds. We find the most prominent difference between the two groups involves the scope of coordination among stakeholders. The U.S. government, primarily via the Department of Interior, acts as de facto coordinating body for migratory bird conservation and plays the central role in oversight, funding, and administration of management in the United States. In contrast, galliform management falls primarily to individual state wildlife agencies, and coordinated conservation efforts have been more ad hoc and unevenly spread across species. Migratory birds benefit from an almost universally greater scope of research and monitoring, scale of habitat conservation, and sophistication of harvest management compared with galliforms. Galliform harvest management plans, in particular, are less likely to use measurable objectives, reporting of uncertainty in population parameters, and explanation of harvest management techniques. Based on a review of species status lists (e.g., the U.S. Endangered Species Act), we found no evidence that galliforms were more frequently listed than migratory species. Regional trend estimates from the North American Breeding Bird Survey (BBS) were more likely to be negative for galliforms over the period 1966–2015, but this was primarily driven by Northern Bobwhite (Colinus virginianus). Data to assess galliform population status are generally poor, which complicates assessment for roughly half of galliform species. Increased support for coordination among state agencies and other stakeholders, similar to that applied to migratory birds, could help to ensure that galliform conservation is poised to tackle forthcoming challenges associated with global change.

Resumen

La Ley del Tratado de Aves Migratorias (LTAM) es fundamental para la conservación de las aves en los Estados Unidos, a través de la protección de las aves migratorias y como catalizador de un siglo de conservación coordinada de las aves. Si bien más de 1.000 especies están protegidas por la LTAM, de las especies vivientes de aves nativas de los Estados Unidos continentales, solo 20 especies pertenecientes al orden Galliformes están explícitamente excluidas. El manejo de los Galliformes ha ocurrido en gran parte sin supervisión federal directa, colocando a este grupo en un camino de conservación fundamentalmente diferente durante el siglo que siguió a la aprobación de la LTAM. En este artículo, revisamos el contexto histórico y la justificación biológica para la exclusión de los Galliformes de la LTAM, y sintetizamos cómo su conservación actual difiere de la de las aves migratorias. Encontramos que la diferencia más destacada entre los dos grupos implica el alcance de la coordinación entre las partes interesadas. El gobierno de los EEUU, principalmente a través del Departamento del Interior, actúa como organismo coordinador de facto para la conservación de las aves migratorias y desempeña un papel central en la supervisión, financiación y administración del manejo en los Estados Unidos.

En contraste, el manejo de los Galliformes recae principalmente en las agencias estatales individuales de vida silvestre, y los esfuerzos de conservación coordinados se han distribuido más ad hoc y de manera desigual entre las especies. Las aves migratorias se benefician de un alcance casi universalmente mayor de investigación y monitoreo, de escala de conservación del hábitat y de sofisticación del manejo de la cosecha, en comparación con los Galliformes. Los planes de manejo de la cosecha de los Galliformes, en particular, tienen menos probabilidades de utilizar objetivos medibles, de informar sobre la incertidumbre en los parámetros de la población y de explicar las técnicas de gestión de la cosecha. Tomando como base una revisión de las listas del estatus de las especies (e.g., Ley de Especies en Peligro de EEUU), no encontramos evidencia de que los Galliformes se incluyan con más frecuencia que las especies migratorias. Las estimaciones de tendencias regionales de la Encuesta de Aves Reproductoras de América del Norte tuvieron mayor probabilidad de ser negativas para los Galliformes durante el período 1966–2015, pero esto fue impulsado principalmente por Colinus virginianus. Los datos para evaluar el estatus poblacional de los Galliformes son en general deficientes, lo que complica la evaluación de aproximadamente la mitad de las especies de Galliformes. Un mayor apoyo para la coordinación entre las agencias estatales y otras partes interesadas, similar al que se aplica a las aves migratorias, podría ayudar a garantizar que la conservación de los Galliformes esté preparada para abordar los próximos desafíos asociados con el cambio global.

INTRODUCTION AND BACKGROUND

The future of North American avifauna was grim in the early years of the 20th century. Overharvest of birds for meat, feather, and egg markets, coupled with widespread habitat loss and degradation, had decimated bird populations that were once thought inexhaustible (Bean and Rowland 1997, Dorsey 1998). The passenger pigeon (Ectopistes migratorious), Carolina Parakeet (Conuropsis carolinensis), and Heath Hen (Tympanuchus cupido cupido) sat on the brinks of their eventual extinctions (Bucher 1992, Johnson and Dunn 2006, Burgio et al. 2017). Then in 1916, the United States entered into a landmark treaty with Great Britain, which acted on behalf of Canada, to protect migratory birds (39 Statue 1702). The U.S. Congress passed the Migratory Bird Treaty Act of 1918 (16 USC Chapter 7, Subchapter II; hereafter MBTA), which was instrumental in eliminating market hunting and forestalling bird population declines of the era. It also set the stage for a century of progress in avian conservation in North America, as additional migratory bird treaties were signed throughout the 20th century with Mexico (50 Statue 1311), the former Soviet Union (T.I.A.S. 9073), and Japan (25 UST 3329, TIAS 7990).

To qualify for protection under MBTA, species must belong to “a family or group of birds” named in either the Canadian or Mexican Conventions, and be documented by an ornithological authority (e.g., the American Ornithological Society) as native or naturally occurring within the United States or its territories. Some birds are also protected under MBTA based solely on specific listings in the Japanese or Russian Conventions, regardless of whether they are native to the North American continent (e.g., Chinese Pond-heron [Ardeola bacchus], Hodgson’s Hawk-Cuckoo [Cuculus fugax]; USFWS 2020). Currently, 1,093 species meet at least one of these criteria and are formally protected by MBTA (USFWS 2020). This list is updated periodically to reflect changes in taxonomy (USFWS 2020), and removal of species from the protected list has occurred via amendments to the act by Congress (e.g., 118 Statue 2908, 3071–72). By rule, 23 families of birds (Supplementary Material Table S1) are explicitly excluded from MBTA protection because they are not expressly mentioned in any of the International Conventions (USFWS 2020), and a large number of species introduced to the U.S. are also excluded (USFWS 2020). We will focus exclusively on species naturally occurring in the continental U.S., unless otherwise noted, and we will also refer to all birds protected by MBTA as “migratory birds”, irrespective of the biological migratory status (described further below).

Of the 23 families excluded from MBTA by rule, only 4 families are resident to the continental U.S. Five additional excluded families are endemic to Hawaii, native to U.S. territories, or occur in Mexico and Central America (Supplementary Material Table S1; USFWS 2020). The remaining 14 excluded families include either species introduced to the United States or its territories, or those occurring only as irregular vagrants (Supplementary Material Table S1). Among the 4 families resident to the U.S., Psittacidae includes 2 species that were formerly resident but were extirpated from the U.S. (Thick-billed Parrot [Rhynchopsitta pachyrhyncha], Snyder et al. 2020) or driven to extinction (Carolina Parakeet, Snyder and Russell 2020) Interestingly, the Carolina Parakeet was heavily hunted for the millinery trade, and the last captive Carolina Parakeet died at the Cincinnati Zoo in 1918 (Burgio et al. 2017), the very year that MBTA was signed into law. The remaining 3 families include Phasianidae, Odontophoridae, and Cracidae, and they are represented by 13, 6, and 1 U.S. species, respectively (Supplementary Material Table S1).

Thus, in comparison to >1,000 species afforded formal federal protection under the MBTA, only 20 extant species that are both native and resident to the continental U.S. are formally excluded (Table 1). Each of these 20 species are members of the order Galliformes (hereafter “galliforms”). By virtue of exclusion from MBTA, the conservation of galliforms in the U.S. has followed a fundamentally different trajectory compared with migratory species. MBTA made illegal the unpermitted possession of migratory birds, their feathers and eggs, and, importantly, provided legal authority for federal oversight of migratory bird management. This empowered the U.S. government, through the Department of the Interior, to enforce the Act and regulate allowable take under federal law. It also led to development of coordinated, science-based management of migratory birds over the following century. These advances are perhaps best illustrated by migratory waterfowl (Anderson et al. 2018), whose present-day management involves federal coordination of standardized population monitoring, comprehensive harvest management, and dedicated funding for large-scale habitat protection and management, all at an international scale (Humburg et al. 2018). Responsibility for management of galliforms, most of which are harvested recreationally as game birds, falls almost exclusively to individual states, and is typically administered by state wildlife or natural resource agencies (Dahlgren et al. 2021, Williams et al. 2021).

Our objective was to compare and contrast the conservation of native galliform birds in the United States with that of species protected under MBTA. We first review the historical context for species’ inclusion under MBTA and contrast that with our present understanding of galliform natural history. We then summarize galliform management in the U.S., highlighting key differences that have resulted from MBTA exclusion, and conclude by reviewing the present status of galliform populations.

We focus throughout on extant species that occur as resident birds within the continental U.S., although we make reference to species occurring elsewhere (e.g., residents of a U.S. territory or incidental vagrants), extinct species, and non-native species where necessary. Where relevant we also draw direct comparisons between galliforms and waterfowl, which provide more direct comparisons with a group of species with comparable management goals (e.g., human harvest; Williams et al. 2021). We used a current checklist of the American Ornithological Society (Chesser et al. 2020) for taxonomic naming convention and to delineate North American species from those occurring elsewhere, and used species accounts from the Birds of the World (Billerman et al. 2020) to establish species’ residency status, inference about migratory behaviors, and other characteristics of natural history. We obtained boundaries of species’ distributions for native non-migratory birds from Bird Life International (datazone.birdlife.org) and use these to infer geographic ranges of all galliform species.

Galliforms and the History of MBTA

Historic motivation for an international treaty protecting birds was rooted in the recognition that actions of one nation can affect availability of birds to citizens of another, given migration across international borders. The role of migratory birds as a public food resource, and the importance of insectivorous birds in providing crop protection, were recognized in the early 1900s and used to justify the original migratory bird convention with Canada (Dorsey 1998). Further justification for bird protection stemmed from precipitous declines linked to overharvest for meat and feather markets and personal recreation (e.g., spring hunting of waterfowl by sportsman’s clubs; Dorsey 1998), but these issues were not exclusive to migratory birds. The Heath Hen was extirpated from mainland U.S. by the early 20th century as a result of overharvest, with the subspecies eventually going extinct in 1932 on Martha’s Vineyard (Johnson and Dunn 2006), and early advocates for migratory bird protections concurrently voiced concerns over galliform populations and overharvest (Hornaday 1916, Dorsey 1998).

The problem of widespread overharvest of galliforms was therefore well recognized during the early 20th century, yet federal legislation focused exclusively on migratory birds. This discrepancy was certainly rooted in the interstate and international nature of bird migration. Early conservationists recognized that federal laws for bird protection would be challenged in court, and that their persistence would require a constitutional footing (Dorsey 1998). Regular crossings of state boundaries by migratory birds could be analogous to interstate commerce, which falls within the Federal Government’s power to regulate under Article 1 Section 8 (U.S. Constitution, Article I, Section 8). This had been the primary justification used to support the Weaks-McLean Act of 1913, the earliest effort to enact federal bird protection, but was immediately challenged as insufficient to overrule states’ rights (Dorsey 1998). However, the U.S. President is granted authority to enter treaties with other nations (U.S. Constitution, Article II, Section 2), and such treaties are considered supreme law, superseding authority of individual states (U.S. Constitution, Article 6). Collectively, these provided proponents with a stronger constitutional defense for the MBTA (Missouri vs Holland 1920; 252 US 416). Motivation for excluding galliforms from MBTA almost certainly arose because upland game birds do not, on average, undertake long-distance migrations, and international treaties and federal oversight were likely perceived as less necessary for their protection.

Present-day protections under MBTA, however, are not dependent on actual bird migration or crossing of international borders. For example, the Carolina Chickadee (Poecile carolinensis) and Black Rosy-finch (Leucosticte atrata) are included on the list of MBTA species (USFWS 2020), despite not occurring outside the contiguous U.S. (Johnson 2020, Mostrum et al. 2020) . Furthermore, many species generally considered non-migratory resident birds are covered by MBTA; examples include most species of woodpeckers (e.g., Bull and Jackson 2020, Lowther et al. 2020) and jays (e.g., Walker et al. 2020, Curry et al. 2020). Inconsistent MBTA protection for some species of birds that do not actually migrate is explained by inclusion of entire families in both the original Mexican and Canadian conventions and their subsequent amendments, which provides blanket protections to all members of the family irrespective of their biological migration status. The lone exception is for introduced species, which are explicitly excluded from MBTA regardless of family membership (USFWS 2020).

It is also likely that international exchange of galliforms is common, albeit not at the scale, frequency, and regularity typical of migratory species. Present-day ranges of 17 native U.S. galliforms occur in at least one MBTA treaty nation other than the U.S., and nearly all of these have accepted ranges overlapping international borders (Table 1; Figure 1). In cases where habitat exists on each side of a border, it is safe to assume individuals move between countries. Furthermore, many galliforms exhibit directional movements between distinct summer and winter ranges (i.e. migration), and some of these galliform migrations cross international boundaries. For example, Tack et al. (2012) and Smith (2012) documented regular seasonal migrations of Greater Sage-grouse (C. urophasianus) from breeding habitat in Alberta, Canada, to wintering areas in Montana, USA. Certain populations of both Willow (Lagopus lagopus) and Rock Ptarmigan (L. muta) migrate en masse for hundreds of kilometers between breeding and wintering ranges (Hannon et al. 2020, Montgomerie and Holder 2020). In the case of Willow Ptarmigan, wintering congregations of birds in Manitoba, Canada, were observed up to 800 km south of the nearest known breeding populations (Hannon et al. 2020), and Rock Ptarmigan migrate between Greenland and Iceland (Lyngs 2003), crossing hundreds of kilometers of open ocean in the process. These observations imply that ptarmigan are capable of migrating between Alaska and Canada, or perhaps even crossing the Bering Strait and traveling between Alaska and Russia, although we are not aware of either circumstance being documented. The major distinction between birds protected by MBTA, and galliforms, is therefore the regularity at which migration across international borders occurs within avian families, and not whether individual species meet the definition of an international migrant. However, in at least some cases entire families of birds are protected by MBTA, despite being comprised largely of non-migrant species (e.g., Paridae; USFWS 2020).

Coordinated Bird Conservation

The U.S. federal government, largely via the Department of the Interior and its component agencies, plays a central role in coordinating research, monitoring, and management of migratory birds. Such coordination was born of necessity in implementing provisions of MBTA (Anderson et al. 2018). The Department of the Interior became legally obligated to regulate take of migratory birds, which inextricably linked the U.S. government to permit legal take, prosecuting illegal take, and providing oversight of research activities. Through time, numerous coordinated efforts, such as habitat protection and research activities, were developed as they became necessary to support this large-scale management. As a group, galliforms lack a central coordinating body, but collaboration and cross-jurisdictional management is still achieved in practice through a variety of other mechanisms. Collectively we found that differences in the scope and structure of coordination reflect the biggest differences between migratory bird and galliform conservation, and below we summarize these differences in the following areas: (1) conservation planning and implementation, (2) research and population monitoring, (3) habitat management, (4) harvest management, and (5) translocations and introductions.

Conservation Planning and Implementation

Flyway Councils (Lincoln 1935, Anderson et al. 2018) and Migratory Bird Joint Ventures (Anderson et al. 2018, Humburg et al. 2018) are 2 examples where federal coordination fosters large-scale collaborative management of migratory birds across stakeholder groups. Administrative flyways were established to aid in managing migratory bird harvest along 4 biological flyway boundaries, with management governed by a council of state and provincial wildlife administrators who are advised by a technical committee comprised of avian biologists (USFWS 1959, Anderson et al. 2018; see further description in the Harvest section). Though Flyway Councils initially focused much of their collaborative efforts on waterfowl harvest, and that remains a primary objective, their role has evolved to focus on conservation of migratory birds in general including game and non-game species (USFWS 1959, Jahn and Kabat 1984). Flyway Councils have collaborated to create management plans, direct research, improve population monitoring, survey hunters, and provide funding for habitat projects (Jahn and Kabat 1984).

Migratory Bird Joint Ventures were established in the mid-1980s through direction of the North American Waterfowl Management Plan to provide coordinated conservation planning for migratory birds (NAWMP 1986, NAWMP 2018). Joint Ventures are generally delineated based on ecoregional boundaries, although three joint ventures focus on species or species groups of waterfowl. Base funding for Joint Ventures is provided by congressional appropriation administered through the United States Fish and Wildlife Service (USFWS), and most (but not all) Joint Ventures are run as a component of USFWS. Since their inception, Joint Ventures have facilitated collaboration among over 5,700 partners and assisted in habitat conservation on 27 million acres (USFWS 2018). Although focused in the name on migratory birds, many regional Joint Ventures include non-migratory birds as priority species such as Northern Bobwhite, Lesser Prairie-chicken (T. pallidicinctus), and Greater Sage-grouse.

For galliforms, some of the best-developed collaborative efforts have come through working groups of the national Associations of Fish and Wildlife Agencies (AFWA) and affiliated regional fish and wildlife organizations (e.g., Western Association of Fish and Wildlife Agencies; WAFWA), which represent formalized cooperatives of state fish and wildlife agencies (Supplementary Material Table S2). The majority of galliform collaborations in the U.S. are affiliated with a working group of one or more of these associations (Supplementary Material Table S2), which can be considered in many ways analogous to the cooperative structure represented by flyway councils and joint ventures for migratory birds. While many working groups are regional and focus on single species or species groups, AFWA’s Resident Game Bird Working Group is noteworthy for being broadly concerned with all galliforms, including non-native species.

One major role of association working groups has been the development of species status assessments and management plans (Supplementary Material Table S3). In some cases, these plans provide the only documentation for regional- or range-wide status of individual galliforms, and their development provides collaborative opportunities for biologists working throughout species’ ranges. Not all galliforms are represented by a species plan, although in some cases state- or region-specific plans have been developed for these species (Supplementary Material Table S3). To our knowledge conservation planning efforts have been undertaken in some capacity for 14 of the 20 species of U.S. galliforms (Supplementary Material Table S3). These have been primarily species-specific efforts, with the lone exception reflected in the Western Quail Management Plan (Zornes and Bishop 2009) which covers 6 species of quail in the Western U.S. Thus, coordinated management planning for galliforms with a single-species focus differs fundamentally from migratory birds, for whom large-scale planning efforts such as the North American Waterfowl Management Plan (NAWMP 2018) or regional Shorebird Conservation Plans (www.shorebirdplan.org) more typically present a unified planning framework across species.

Coordinated efforts for species-specific galliform conservation often arise from necessity following drastic population declines, including the potential listing of species under the U.S. Endangered Species Act (ESA). Prominent examples include the Lesser Prairie-chicken Initiative, Greater Sage-grouse Initiative, and National Bobwhite Conservation Initiative. The Lesser Prairie-chicken and Greater Sage-grouse Initiatives are both components of the U.S. Department of Agriculture (USDA) Working Lands for Wildlife program. Administered by the Natural Resources Conservation Service, these programs exist to help private landowners apply habitat conservation practices, particularly in agriculture, to benefit species of conservation concern (Van Pelt et al. 2013). The National Bobwhite Conservation Initiative exists as a collaboration of 25 state fish and wildlife agencies and other conservation organizations. Originally conceived via the Southeastern Association of Fish and Wildlife Agencies Southeastern Quail Study Group, the National Bobwhite Conservation Initiatives goal is to develop a strategic effort to restore wild populations of Northern Bobwhite to historic benchmark levels (NBCI 2011; bringbackbobwhites.org).

In contrast to these 3 prominent examples motivated by high-profile population declines, many other galliform collaborations have struggled to transition from planning to implementation. For example, the AFWA Resident Game Bird Working Group helped facilitate the creation of multiple range-wide management plans, including the Western Quail Management Plan (Zornes and Bishop 2009), Ruffed Grouse Conservation Plan (Dessecker et al. 2006), and Spruce Grouse Continental Conservation Plan (Williamson et al. 2008). In each case, widespread implementation has not occurred in the more than a decade following their publication, perhaps due to lack of funding mechanisms for implementation. The more successful examples we give above received significant federal funding, suggesting that federal support has been a key to moving past the planning stage to implement broad-scale coordinated conservation of galliforms at national or international scales. However, these few examples were exceptions, rather than rules, which highlights significant variability in the degree to which federal resources are applied to galliform conservation.

Overall, the scope of coordinated conservation for migratory birds in the U.S. is generally greater, and applied more consistently across species, than for galliforms. This is due in large part to the formalized coordination processes reflected in the flyway councils and migratory bird joint venture programs. That is not to say that coordinated conservation for galliforms is nonexistent, and in fact a number of cooperative groups have been established despite a general lack of federal involvement. Furthermore, for birds protected by MBTA there is significant variation in the focus of coordination among species, with both Flyway Councils and individual joint ventures often focusing on priority species.

Research and Monitoring

Examples of coordinated monitoring that were originally motivated by migratory gamebird management include the North American Bird Banding Program (now administered by the U.S. Geological Survey Bird Banding Laboratory [BBL]; Crissey 1955, Smith 2013, Anderson et al. 2018), the Waterfowl Breeding Population and Habitat Survey (Smith 1995), and the Migratory Bird Harvest Information Program (Ver Steeg and Eldon 2002). Each of these efforts has resulted in long-term, species-specific data for waterfowl and other migratory game species’ population trends, habitat availability, and demographics. These datasets are available at a continental scale, have been instrumental to advancing our understanding of species’ full annual cycles, and are critical for implementing management (Nichols et al. 2007). The BBL permits banding and maintains a banding and recovery database for all migratory species, and through this facilitates additional coordinated efforts such as the Monitoring Avian Productivity and Survival (MAPS) program to better estimate demographic parameters from songbird banding data (DeSante et al. 1995). Another key coordinated effort is the North American Breeding Bird Survey (BBS), which is a citizen-science effort that is jointly coordinated by the U.S. Geological Survey Patuxent Wildlife Research Center and Environment and Climate Change Canada. While BBS tracks populations of all birds encountered during surveys (migratory, non-migratory, and non-native), its sampling design was initially developed around the breeding phenology of neotropical migrant songbirds. Data from each of these monumental efforts are, importantly, centrally located, curated, and publicly available, which facilitates widespread use and advancement of avian science.

Coordinated monitoring of galliforms across state and provincial boundaries is relatively uncommon. Most state fish and wildlife agencies employ some form of monitoring of their most popular game species or those of conservation concern. Methods for population monitoring are similar to those employed for waterfowl, including count-based surveys (e.g., Garton et al. 2011, 2016), banding (e.g., Zablan et al. 2003), and parts collection (e.g., Sands and Pope 2010, Hagen et al. 2018). In some cases, this has produced long-term data series, but these tend to be state- and species-specific, and in general lack the same breadth and depth of data as are available for waterfowl. To illustrate this discrepancy, we point out that through the Waterfowl Breeding Population and Habitat Survey, estimates of annual abundance are available for nearly all species of North American waterfowl at a continental scale for over half a century. These data can be coupled with banding and harvest recovery data collected at similar scales for many species, which is now providing relatively unprecedented insights into species’ population regulation and effects of anthropogenic stressors (e.g., Zhao et al. 2019). In contrast, population time-series data at similar scales are available for only a handful of galliforms, primarily sage-grouse and Lesser Prairie-chicken (e.g., Garton et al. 2011, 2016), producing a scenario where it is difficult to assess range-wide status for many galliforms (discussed further in the Present Status section) and where the ability to address novel threats may be inherently limited. Galliforms are represented in other large-scale monitoring efforts, such as the Christmas Bird Count (https://www.audubon.org/conservation/science/christmas-bird-count) and eBird (eBird.org), but to our knowledge systematic efforts to assess galliform trends from these databases do not exist.

Coordinated galliform research also tends to be species-specific and local, with larger regional cooperative projects providing exceptions rather than the rule. For example, the Appalachian Cooperative Grouse Research Project (Devers et al. 2007) combined efforts by multiple stakeholders and research institutions to implement a broad-scale research program on Ruffed Grouse (Bonasa umbellus) in the southeastern extent of the species’ range. Other studies on Northern Bobwhite (Colinus virginianus; Sandercock et al. 2008) and Greater Sage-grouse (Taylor et al. 2012) have combined published data in meta-analyses for inference on demographic mechanisms behind population processes. However, each of these studies explicitly acknowledged that inconsistent data collection among research groups complicated their efforts. We believe that lack of a central coordinating body to provide guidance on data collection methods, and to maintain a repository of cleaned and vetted datasets has and will continue to limit the scope of galliform research and science-based management in the United States.

An area where federal coordination has contributed substantially to both migratory bird and galliform conservation is via funding mechanisms for research. One particularly important source is funds associated with the Wildlife Restoration Act, commonly referred to as the Pittman-Robertson Act, which uses a federal excise tax placed on firearms and ammunition to fund wildlife conservation projects that are administered by state agencies. To illustrate the importance of these federal funds to galliform research, we searched the table of contents for the Journal of Wildlife Management, Wildlife Society Bulletin, The Auk: Ornithological Advances, and The Condor: Ornithological Applications during the years 2004–2018 for the term “game birds”. From 255 articles, we collected funding information from 85 studies on galliforms. Most of the articles we reviewed (63 of 85) were funded by multiple sources including federal, state, university, and private organizations. State funding contributed to 56 of 85 studies, and federal and private sources were used in 51 and 48 studies, respectively. Pittman-Robertson Act funds were the most commonly-cited source of federal funding (21 out of 51 federally funded studies). While this review is not comprehensive, it does demonstrate that federal funding by the U.S. government, particularly that associated with the Pittman-Robertson Act, contributes to much contemporary research on galliforms.

Research and monitoring of galliforms, as a whole, has lagged behind that of migratory birds. This discrepancy is most clearly illustrated when comparing galliforms to waterfowl (Williams et al. 2021), and occurs in large part because waterfowl have benefited from nearly a century of coordinated data collection, at a continental scale, for nearly all species. Certain galliform species, however, have been the subject of significant research and monitoring, in some cases much more so than lesser-studied non-game migratory birds. However, even for species such as Northern Bobwhite and Ruffed Grouse, among the most studied birds in North America, we lack standardized protocols for population monitoring or centralized databases to facilitate large-scale synthetic research efforts.

Habitat Management

Although variable among species, funding for large-scale conservation of migratory bird habitat is available through multiple federal initiatives, often backed by prominent pieces of federal legislation. These include the Migratory Bird Conservation Act of 1929 (16 U.S.C. 715–715d, 715e, 715f–715r) and the Migratory Bird Hunting and Conservation Stamp Act of 1934 (16 U.S.C. 718–718j, 48 Statue 452), which together set the stage for expansion of the National Wildlife Refuge System to provide habitat for migratory birds. Significant additional funding to acquire and manage these refuges is provided through the Migratory Bird Hunting and Conservation Stamp program, often referred to as the Federal Duck Stamp. Between its inception in 1934 and 2015, the Federal Duck Stamp program generated >$866 million used to purchase or lease >2.4 million ha of wetland habitat in the U.S. (Anderson et al. 2018). Furthermore, the North American Waterfowl Management Plan (NAWMP 2018) provides a framework to prioritize waterfowl habitat management, and through the migratory bird joint ventures, fosters coordination of habitat management for all migratory birds. Nonprofit, non-governmental organizations (NGO) such as Ducks Unlimited (www.ducks.org) and Delta Waterfowl (www.deltawaterfowl.org) have also been central in efforts to protect and enhance habitat for waterfowl and other wildlife. There have also been significant efforts to conserve habitat for waterfowl and other migratory birds on tribal lands, in some cases resulting in millions of acres of improvement and conservation of wetland habitat (Miersch 1998). As an outcome of these and other important conservation measures not explicitly related to migratory bird management, such as the North American Wetland Conservation Act (103 Stat. 1968; 16 U.S.C. 4401–4412), waterfowl populations have increased by an estimated 56% over the last half-century (Rosenberg et al. 2019). Because at least some of these efforts focus on habitat shared with galliforms (e.g., upland nesting habitat for dabbling ducks that is also used by prairie grouse), there have certainly been indirect benefits of waterfowl habitat conservation to some galliform populations.

Habitat management targeted explicitly towards galliforms (i.e., where benefiting galliforms is the primary goal) is achieved through private, state, and NGO efforts, with a few specific examples of large-scale, federally-coordinated programs that are directly focused on galliform habitat management such as those associated with the Sage-grouse and Lesser Prairie-chicken Initiatives (see Coordinated Bird Conservation section). State fish and wildlife agencies traditionally lead management of galliform habitat on public lands, such as state forests or wildlife management areas, with the scope and scale depending on a variety of factors related to each agency’s mission, local objectives, funding mechanisms, and land base. Large-scale federal efforts to conserve galliform habitat on public lands have generally been limited to species listed or proposed for listing under the ESA. One example is the Greater Sage-grouse, a species that has been the subject of ESA petitions and subsequent litigations for more than 20 years (Stiver 2011). This in turn has led to a number of major land management initiatives by both the Bureau of Land Management and U.S. Forest Service, which collectively manage nearly 60% of all sage-grouse habitat in the United States (Connelly 2013). In certain circumstances, specific federal management areas, such as individual National Wildlife Refuges or National Forests, may also include habitat for galliforms under their management objectives.

Opportunities for galliform conservation work on private lands have traditionally been voluntary, and often reliant on federal funding programs (Burger et al. 2006, Ciuzio et al. 2013, Elmore and Dahlgren 2016, Dayer et al. 2018). Federal agricultural policy, set by the USDA and funded via the Farm Bill, provides several incentive-based private lands programs that may benefit galliforms. These programs are usually administered through the Natural Resources Conservation Service (NRCS) or U.S. Forest Service (summarized in Ciuzio et al. 2013). While programs such as the Conservation Reserve Program (CRP) may be designed to address large-scale environmental problems like soil erosion and water quality, they often benefit wildlife including galliforms (Riffell et al. 2008, Schroeder and Vander Haegen 2011, Ross et al. 2016), and through time have been updated to include programs specifically targeted to upland game bird habitat (Burger et al. 2006). Individual state agencies may also offer incentive programs or technical assistance to landowners, but such programs are not ubiquitous. NGOs focused on individual species (Supplementary Material Table S2) are also central to habitat conservation for galliforms, often with efforts coordinated at large scales and that cross state lines. These organizations influence habitat management through activities that range from lobbying at the federal level to affect congressional appropriations and land management policies, to working with individual private landowners on habitat management practices (Arnett and Southwick 2015). Cooperative Extension Offices, which work in partnership with the US Department of Agriculture and are typically housed at state land-grant universities, have also provided education and outreach programs focused on private lands management for a number of galliform species (Benson 1977).

Galliform habitat management has traditionally focused on relatively local scales, which matches the (generally speaking) more sedentary nature of these species. In contrast, migratory birds have benefited from much larger-scale habitat conservation efforts, perhaps better matching the large scale of their full annual cycle habitat needs. Most prominent galliform population declines have occurred at large scales, however, where local management efforts may be ineffective if not paired with coordination affecting change at the larger scales that match the full scope of decline (e.g., Van Pelt et al. 2013, NBCI 2011). Broad-scale programs that benefit galliform habitat, such as CRP, are sensitive to commodity prices and federal appropriations (Rashford et al. 2011, Dayer et al. 2018). Similarly, funding for habitat by individual states often relies on revenue from hunting license fees or federal excise taxes on firearms and ammunition, and declining hunter participation could reduce availability of such funds (Burger et al. 1999, Arnett and Southwick 2015). Thus, there will be challenges for broad-scale conservation of galliform habitat in the future, and land managers may need to cooperate on novel programs, additional revenue streams, or new regulatory measures to meet these challenges (Hansen et al. 2018).

Harvest Management

To manage migratory bird harvest under MBTA, the USFWS works with Flyway Councils to review and implement waterfowl harvest strategies at state and flyway levels. The flyway system of management was proposed by Lincoln (1935), was implemented in 1948, and consists of four major administrative flyways (Atlantic, Mississippi, Central, and Pacific). These flyways were based on predominant migration routes across the U.S. and Canada, as understood at the time based on band returns, and their use continues today. Management within each flyway is governed by a council consisting of state and provincial representatives and supported by a technical committee comprised of waterfowl and avian biologists from each flyway (Anderson et al. 2018). Subcommittees are formed to address specific management issues (e.g., harvest of a particular species or group of species), and these subcommittees are typically comprised of technical committee members from states or provinces most directly affected by those management decisions. Technical Committees provide harvest and management recommendations to the Flyway Councils, which in turn present recommendations to USFWS. In considering these recommendations, USFWS develops a management framework that is implemented by individual state natural resource agencies; because MBTA regulates take of migratory birds under federal law, individual states are obligated to work within the USFWS framework for setting harvest regulations.

Harvest management of galliforms generally occurs without formal interstate coordination. Some species-specific working groups (Supplementary Material Table S2) hold regular meetings to promote collaboration and sharing of ideas, and several taxa-specific conferences and symposia exist to present the latest science on galliform management (Supplementary Material Table S4). However, harvest implementation is largely independent among states, which may differ in management objectives, species’ status, and approach to harvest regulation. Absent the federal oversight provided through MBTA, management of galliform harvest is likely more sensitive to political influence in the decision process, particularly where harvest regulations are approved legislatively as state law, rather than directly by the natural resource agencies themselves. Harvest of migratory birds is not free of such influence, however, the broader decision process used by the flyway councils requires an inherently greater degree of consensus building, and federal regulation of harvest ensures local-decisions must fall within the particular set of regulatory sideboards resulting from that consensus. Some states may stratify harvest regulations within state boundaries (e.g., different regulations within certain defined zones or regions), and in some cases these strata may be defined by ecological criteria such as variation in local density (Dahlgren et al. 2021). However, across most species galliform harvest regulations are structured to a greater extent by geopolitical boundaries than by biological populations. Formal interstate regulation of galliform harvest is probably unnecessary for most species; large-scale migrations necessitate coordinated harvest of migratory gamebirds, whereas in galliforms they generally do not. However, states could likely benefit from a greater degree of cooperation in developing best practices and evaluating and implementing more standardized approaches to galliform harvest management (Dahlgren et al. 2021, Williams et al. 2021), which has been one clear outcome of the flyway council model for migratory birds.

The degree to which harvest management decisions are data-driven is also variable among galliforms. Based on a survey conducted in the early 2000s (Sands and Pope 2010), 55.8% of responding biologists reported applying population monitoring data when setting harvest regulations, which implies that slightly less than half of galliform harvest management decisions were not based on knowledge of current population status (Sands and Pope 2010). However, even within the slightly more than half of the state agencies that incorporate population data in the management process, the relative sophistication of approaches varies widely. Artelle et al. (2018) reviewed North American wildlife harvest management systems to assess the use of scientific approaches for game management (although see Mawdsley et al. 2018). We retrieved the authors’ online database, and further focused on the 164 galliform management systems contained within it. Their database illustrated that harvest management for galliforms involved lower use of measurable objectives, less reporting of uncertainty in population parameters, and less frequent explanation of harvest management techniques when compared to other game animals (Table 2). Although Artelle et al. (2018) did not consider migratory birds in their review, many standard practices for migratory bird harvest management via Flyway Councils, including formal adaptive harvest management (AHM), overcome these limitations.

The AHM decision process incorporates uncertainty and stakeholder objectives into a modeling framework used to guide harvest regulations (Nichols et al. 2007). AHM is applied most prominently to several high-profile species of waterfowl, including two regional breeding stocks of Mallard (Anas platyrhynchos), and Wood Duck (Aix sponsa), Ring-necked Duck (Aythya collaris), American Green-winged Teal (Anas crecca), and goldeneyes (Bucephala spp.) as part of a multi-species process in the Atlantic Flyway (USFWS 2020). Additional AHM processes have developed for American Black Duck (Anas rubripes), Northern Pintail (Anas acuta), and scaup (Aythya spp.; USFWS 2020). A benefit of AHM is explicit accounting of uncertainty at each level of the decision-making process, helping managers understand which regulations to implement based on current population state and available demographic information. This approach also identifies data deficiencies to better prioritize research needs and guide coordinated data collection. AHM also benefits from an interactive planning process, where the outcomes of prior decisions are evaluated in a feedback loop to inform future decisions.

While some states use AHM to manage galliform harvest, implementation is relatively uncommon and varies by state, species, and level of sophistication (Powell et al. 2011, Robinson et al. 2017, Stevens et al. 2017, Dahlgren et al. 2021). For example, AHM was used to incorporate multiple objectives from different stakeholders along with ecological and environmental factors to provide optimal management decisions for Wild Turkeys in New York (Robinson et al. 2017), and was demonstrated for this species more broadly across a range of harvest rates and productivity metrics by Stevens et al. (2017). As noted above, not all harvested migratory game birds are regulated under AHM; in fact, the full process is only applied to a few key species of waterfowl. However, harvest of most migratory game birds is managed using some level of population data to inform the regulatory process. More widespread application of data-driven approaches to galliform harvest, whether as a formal AHM decision process or otherwise, would likely encounter significant data limitations and considerable uncertainty for most species (Moa et al. 2017). Traditionally, much research on galliform harvest has searched for evidence of compensatory vs additive mortality (e.g., Devers et al. 2007, Sandercock et al. 2011), which can be notoriously difficult to evaluate accurately (Sedinger and Rotella 2005). Comparably fewer efforts have asked how galliform populations respond to changing harvest regulations in practice (e.g., Guthery et al. 2004). Thus, in addition to insufficient monitoring limiting the ability to track population status, there is likely considerable uncertainty around the ability of harvest management actions to achieve galliform population goals. The more restricted annual home ranges of many galliforms means that uniform, interstate harvest management regulations are not necessary. However, management of galliforms may nevertheless benefit from application of more a uniform suite of approaches to harvest decision making (Dahlgren et al. 2021, Williams et al. 2021), which could be achieved in practice through greater interstate coordination.

An often-overlooked consideration for hunting regulations in North America is the harvest of animals by indigenous groups. Modern sport hunting for both migratory birds and galliforms is typically managed to provide recreational opportunity, while a very different cultural context, that of subsistence and ceremony, normally underlies harvest of wildlife by Native Americans (McCorquodale 1997). Special harvest regulations permit take of migratory birds by Native American Tribes and Alaska’s indigenous inhabitants under MBTA, either through treaty rights in the contiguous United States or as a distinct regulatory process in Alaska via an amendment of MBTA (described below). Harvest of galliforms that occurs on tribal reservations falls under the sovereignty of each nation (Czech 1995), with management based upon tribal conservation objectives and community subsistence needs. Harvest of wildlife by tribal members outside of reservation boundaries has a complex regulatory history (McCorquodale 1999) but is generally expected to conform with individual state game laws that may or may not provide special regulation for tribal harvest of game.

Recent approaches to co-management of migratory birds have been developed as a path forward and could be adopted for harvest management of galliforms. In one effort to improve subsistence harvest management, the Alaska Migratory Bird Co-Management Council (AMBCC) was formed following an amendment to MBTA that provided for harvest of migratory birds by indigenous inhabitants during spring and summer when migratory species are present in Alaska (Migratory Bird Treaty Act, 16 U.S.C. 703–712). This co-management regime integrates the culture and traditional practices of Alaska Native Tribes while meaningfully involving Alaska Natives throughout the process. Galliforms represent an important subsistence food for Alaska Natives, and while not part of the co-management regulatory process, subsistence harvest of galliforms is tracked via the AMBCC harvest assessment program. More widespread application of co-management approaches would increase the diversity of perspectives applied to harvest management of galliforms in the U.S.

While coordinated harvest regulations may be less necessary to facilitate population management compared with migratory birds, one outcome of the coordinated regulatory process for migratory game birds has been more rapid advancement of approaches to harvest management. While these are not applied equally among all migratory species, data-driven approaches to harvest management and regulatory decision-making are used more consistently than for galliforms. More regular coordination among state agencies, including cooperation with tribes, to refine harvest programs could benefit galliform management.

Translocations and Introductions

Translocation is often an important tool used to establish, restore, and augment populations, or to increase hunting opportunities, for a wide variety of wildlife (Wolf et al. 1996, Fischer and Lindenmayer 2000). Under MBTA, the USFWS acts as the central governing body for translocating wild and captive-reared migratory birds. For galliforms, individual states typically regulate liberation within their boundaries, although state agencies other than departments of wildlife may be involved (e.g., state departments of agriculture). In the case of interstate translocation of galliforms, coordination among states is required to facilitate capture in source populations and permit export, with formality of the cooperative relationship varying widely. Wild Turkey represent the most prominent and successful example of conservation translocation in the U.S., if not worldwide. Once reduced to ~30,000 individuals in North America, Wild Turkeys were released through many multi-state and international translocations occurring over several decades (Mock et al. 2002, McRoberts et al. 2020). These efforts led to re-establishment of self-sustaining populations throughout the species’ historic range, and in some cases, introduction into areas not previously occupied by the species. Not all galliform translocations are successful, for a variety of reasons (Sokos et al. 2008), particularly when attempting to augment or restore populations without first addressing the underlying causes of extirpation or decline.

Although important as conservation tools, human-assisted movements can have negative consequences for resident populations through disease transmission, competition, changing predation dynamics, increased potential for hunting violations, dilution of the native gene pool, and introduction of species outside their native range (Brennan 1991, USFWS 2013, Lavretsky et al. 2019). Beyond native species, there is a long history of wildlife managers and private individuals in North America introducing exotic galliforms to provide additional hunting opportunities, with the most prominent examples of successful establishment including Ring-necked Pheasant (Phasianus colchicus), Chukar (Alectoris chukar), and Grey Partridge (Perdix perdix; Dahlgren et al. 2021). The introduction of these non-native species has led to a significant commitment of resources to their subsequent management as game species, and how this has affected resource allocation to native species management is not well understood (Williams et al. 2021). Introduced exotics may also interact negatively with native galliforms; for example, Ring-necked Pheasant females are known to parasitize nests of Greater Prairie-chickens (T. cupido; Westemeier et al. 1998). There is considerable uncertainty regarding population-level effects of these interactions. Somewhat ironically, the introduction of non-native galliforms to the United States is one area where federal assistance, via the USFWS Foreign Game Investigation Program, historically played a role in assisting state wildlife agencies with efforts to establish new game bird species (Williams et al. 2021).

Even among native galliforms, translocations are not without potential negative consequences. Northern Bobwhite have likely been translocated to the extent that genetic differentiation is difficult to detect across their range (Whitt et al. 2017), suggesting significant effects to native genetic diversity. Similarly, the previously mentioned success of Wild Turkey reintroductions has resulted in artificial mixing of population genetics and establishment of the species well outside its historic range, with unclear consequences for population and ecosystem health. Insufficient oversight of galliform releases (both native and exotic) may facilitate unintended consequences, although migratory species are not immune from similar issues. Mallards are extensively captive-raised and released in some regions, primarily by private game clubs to provide opportunity to hunters (USFWS 2013). Allowing these domestic stock birds to “free-fly” and potentially integrate into populations of wild birds is controversial, for many of the same reasons we highlight above for galliforms (Lavretsky et al. 2019). Other examples include so-called “resident” Canada Geese (Branta canadensis), a term used to describe populations of Canada Geese that nest at southern latitudes and generally do not migrate to different wintering areas. In most cases, the establishment of resident Canada Goose populations resulted from liberation of captive birds or purposeful translocation by wildlife agencies involving numerous source populations and subspecies (Atlantic Flyway Council 2011). Resident Canada Geese are now considered over-abundant in many areas, and present numerous challenges because they have adapted to and often occur at the urban-wildlife interface (Atlantic Flyway Council 2011). Thus, while translocations and introductions have occurred with much greater regularity for galliforms, the federal oversight of migratory bird translocations has not prevented the introduction and establishment of non-native populations, nor has it been without unintended negative consequences in a few prominent cases.

Present Status of Galliform Populations

To assess the present status of galliforms, and to provide context to the outcomes of 100 years’ difference in conservation strategies between the two groups in the U.S., we reviewed existing broad-scale (i.e. national or continental) species status assessments (Supplementary Material Table S5). We relied on 3 threat assessment lists that included (1) the ESA list of threatened and endangered species (www.fws.gov/endangered/species), (2) the International Union for Conservation of Nature (IUCN) Red List (www.iucnredlist.org), and (3) the Partners in Flight (PIF) species watch list (www.partnersinflight.org/species). Each species status list was accessed on February 12, 2019. We also evaluated species status using published trend estimates from the North American Breeding Bird Survey (BBS; www.pwrc.usgs.gov/bbs/), and evaluated long-term changes in abundance as a function of breeding biome classification (Rosenberg et al. 2019), each of which we describe further below.

For each species status list, we compared the proportion of galliform species listed with the proportion expected under a null hypothesis of equal representation, and we contrasted this with a similar assessment for waterfowl. The MBTA covers 1,093 species, and 122 North American native bird species are formally excluded from the list, for a sum of 1,215 species. The 20 species of native U.S. galliforms, therefore, represent approximately 1.64% of native North American birds that are available to be listed. If MBTA classification was independent of present species status, we would expect any particular status assessment to include galliforms in approximately 1.64% of its listings. Sixty-eight species of waterfowl are represented on the MBTA list of protected species, including 47 U.S. resident species (including those endemic to Hawaii); the remaining 21 species breed elsewhere and are only occasional vagrants to the U.S. (e.g., Barnacle Goose Branta leucopsis). We chose to use only the 47 resident species, because galliforms lack a comparable group of vagrant species. Thus, for comparison, waterfowl representation on species status lists should approximate 3.86% under a null distribution. We used chi-square tests to determine if status of galliform or waterfowl species differed from expected based on these proportions.

Endangered Species Act

One species of native galliform (Gunnison Sage-grouse) and two subspecies (Masked Bobwhite [C. v. ridgwayi], Attwater’s Prairie-Chicken [T. c. attwateri]) were listed as ESA Endangered Species. There were 101 U.S. bird species and subspecies listed as threatened or endangered under ESA in total, so galliforms comprised 3% of avian listings and did not differ significantly from expectation (χ ² = 1.090, df =1, p = 0.30). Waterfowl listed as threatened or endangered under the ESA were represented by 5 species including 3 Hawaiian endemics (Laysan Duck [Anas laysanensis], Hawaiian Duck [Anas wyvilliana], and Hawaiian Goose [Branta sandvicensis]) and 2 Arctic-breeding sea ducks with restricted distribution (Steller’s Eider [Polysticta stelleri] and Spectacled Eider [Somateria fisheri]), totaling 5% representation. This also did not differ significantly from expectation (χ ² = 0.31, df =1, p = 0.58). Thus, both galliforms and waterfowl do not differ from other birds, and we cannot conclude that galliforms are disproportionately represented on the U.S. List of Threatened and Endangered Species.

IUCN Red List

Five species of U.S. galliforms were included on the IUCN Red List, including 1 listed as endangered, 2 as near-threatened, and 2 as vulnerable (Supplementary Material Table S5). A total of 172 U.S. bird species were included on the Red List in these 3 categories, so the list contained 2.9% representation by galliforms, which did not differ from expectation (χ ² = 1.68, df =1, p = 0.19). Eleven North American waterfowl were included, or 6.4% of red-listed species, which also did not differ from expectation (χ ² = 2.86, df =1, p = 0.09). Despite some overlap with Endangered Species Act listings (e.g., Gunnison Sage-grouse and Hawaiian endemic waterfowl), the IUCN Red List also included more widespread and historically common species, such as Northern Bobwhite, Greater Prairie-chicken, and Greater Sage-grouse for galliforms, and widespread sea ducks with circumpolar distributions such as Long-tailed Duck (Clangula hyemalis) and Common Eider (Somateria mollissima). As with the Endangered Species Act, we could not conclude galliforms were disproportionately represented on the IUCN Red List.

Partners in Flight Watch List

The 2016 revision of the PIF Landbird Conservation Plan (Rosenberg et al. 2016) included status assessment for 448 species of North American landbirds. This assessment differs from the ESA and IUCN Red Lists by explicitly excluding assessment of waterbirds, and thus a direct comparison between native non-migratory birds and waterfowl is not feasible. Furthermore, because PIF considered a smaller number of total species we expected ~4.5% representation of galliforms on the list (20 galliform species divided by 448 evaluated). Two species of galliforms were included on the PIF Red Watch List (extremely high vulnerability) and an additional 5 species were included on the PIF Yellow Watch List (Supplementary Material Table S5) for 7 species total. With 86 species included, galliforms, therefore, represented 8% of listed landbird species. While this percentage appears more extreme, it does not differ significantly from the expected distribution (χ ² = 2.53, df =1, p = 0.11) and so we cannot conclude that among landbirds, galliforms were disproportionately included on the PIF Watch List.

Breeding Bird Survey Trends

The federally-coordinated North American BBS is often used to evaluate large-scale and long-term population trends of North American breeding birds, and BBS data are among the only data available for direct comparison of large-scale, long-term population trends between galliforms and migratory birds. We retrieved BBS regional trend estimates for the period 1966–2015 from the Patuxent Wildlife Research Center online data portal (www.mbr-pwrc.usgs.gov/bbs/). These trends were estimated using a hierarchical Bayesian analysis as described by Sauer and Link (2011), expressed as percent annual change within each region over the 50-year survey period.

We first cross-checked the BBS trend estimates, which included all species encountered on surveys (native galliforms, migratory, and non-native), against a recent supplement to the American Ornithological Society Checklist of North American Birds (Chesser et al. 2020). We then further subset regional trend estimates to only those distinguished with a regional credibility measure rating of “Green”, which represented the most reliable subset of the data (Sauer et al. 2017). We evaluated the general distribution of regional trend estimates for the galliform species represented in the dataset, and compared these with similar distributions for both native migratory birds and for waterfowl. We grouped estimates into 3 categories based on whether 95% credible intervals (CIs) confirmed a net decline (both lower and upper limits were negative), a net increase (both lower and upper limits were positive), or did not deviate from stable (95% CIs contained 0.0), and used a chi-squared analysis to evaluate whether the frequency of observation within these three categories differed significantly for galliforms compared with migratory birds and waterfowl.

We recognize that factors other than regulatory status affect avian population trends, and in particular, it is well-known that long-term population trends differ, sometimes markedly so, among functional groups of birds (Rosenberg et al. 2019). To further consider the generality of differences between galliforms and other birds, we evaluated variability in the distributions of trend estimates among all avian orders represented in the BBS data. This allowed us to ask whether galliform trend estimates differed in a systemic way from all other taxonomic groupings of birds protected under MBTA, or if they were similar to a particular subset of MBTA taxa. We also evaluated the distribution of regional trend estimates for individual galliform species to better-understand whether disproportionate representation within the BBS data might influence our assessment of galliform trends overall.

There are a number of very important caveats to these analyses. The BBS protocols were developed to target migrant songbirds (Sauer et al. 2013), and surveys are conducted primarily during the month of June (Sauer et al. 2013). As year-round residents, galliforms typically breed much earlier, so the temporal coverage of the BBS likely excludes periods of high detection associated with courtship displays of most galliforms. This at least partially explains why only about half of the 20 galliform species are represented in the BBS trend estimates. Therefore, our comparison must be viewed as specific to species and regions adequately surveyed by the BBS.

Of 14,968 regional trend estimates for migratory birds, 728 trend estimates for waterfowl, and 287 trend estimates for galliforms, the data subset to only “Green” credibility ratings contained 6,719, 127, and 96 estimates, respectively. The full dataset contained at least one regional trend estimate for 11 species of galliforms and 24 species of waterfowl, while there were 9 and 17 species, respectively, in the data subset to only green credibility measures. Visual inspection showed some apparent differences in the distribution of trend estimates between galliforms and migratory birds (Figure 2A). Chi-squared analysis confirmed significant differences in the distributions for all migratory birds versus galliforms (χ ² = 7.55, df = 2, p = 0.02) and waterfowl versus galliforms (χ ² = 31.8, df = 2, p < 0.001). Specifically, the distribution of values for galliforms were skewed towards a greater proportion of negative trends, and a lower proportion of positive trends, relative to both migratory species in general and to waterfowl specifically (Figure 2B, D; Supplementary Material Table S5). However, when we explored how individual species contributed to these patterns, we found the majority of extreme negative trend estimates for galliforms (e.g., those with >4% decline) were represented by a single species (Figure 3B), Northern Bobwhite, which is also the galliform species most disproportionately sampled by BBS (Supplementary Material Table S5). The mean trend estimate for all galliforms (–2.2% per year) was greater than for all other orders, but when Northern Bobwhite were removed from the assessment, the mean (–0.1 % per year) and distribution of galliform trends was much more similar to the central tendency for other orders of birds (Figure 3A). Mean BBS trends for Galliformes, absent Northern Bobwhite, were greater than 10 other represented orders, and lesser than 9 other represented orders.

Change in Abundance

It is well-known that avian population trends differ, sometimes markedly so, among ecosystem types (Rosenberg et al. 2019), and this may affect populations of galliforms, or migratory birds, more so than regulatory status per se. Rosenberg et al. (2019) estimated changes in abundance for North American birds, and evaluated the role of breeding biomes in affecting that change, from 1970 to 2019. We retrieved Rosenberg et al.’s database (https://doi.org/10.1126/science.aaw1313), which we further subset, as for the BBS analysis above, to include only native species naturally occurring as breeding birds in North America. We further subsetted to only those breeding biomes with estimates for at least one galliform species. Using the estimates of loss reported by Rosenberg et al. (2019), we evaluated how the net change in abundance differed among galliforms represented in the dataset (13 species), and between galliforms and MBTA-protected species which shared the same breeding biomes. These estimates were derived in large part using BBS data (Rosenberg et al. 2019), and so the caveats we list above with respect to BBS protocols apply here as well.

The average galliform species lost 0.25 million individuals over the 50-year period considered by Rosenberg et al. (2019), but there was widespread variability among species (SD = 6.8 million; Figure 4) ranging from an estimated loss of almost 21 million Northern Bobwhite, to a net gain of 11.4 million Wild Turkey. In contrast, mean loss for migratory species in the same breeding biomes was 6.4 million individuals (SD = 27.4 million), with a much larger range of values (43.8 million gained to 307.5 million lost). Within individual breeding biomes, the relative position of galliform species varied considerably. For example, Northern Bobwhite exhibited far greater loss than nearly all other species in the Eastern Forest biome, whereas within the grassland biome, Greater Prairie-chicken and Sharp-tailed Grouse were estimated with net gains that deviated from most other species (Figure 4). Overall, there is no general pattern in these data to suggest that galliforms consistently gained or lost abundance when compared to migratory birds inhabiting the same ecosystems, and aside from Northern Bobwhite as an outlier, all other represented species fall within the distributions of their respective biomes.

SUMMARY AND CONCLUSIONS

During the century since passage of the MBTA, 20 species of galliforms have been managed in the United States under a conservation model that differs markedly from that of migratory birds. In most cases, management of this group occurred in relative absence of federal oversight, with a net effect of reducing the breadth of collaboration, scale of research and monitoring, scope of habitat conservation, and sophistication of harvest management relative to migratory birds. Galliform conservation is not without parallel efforts in each of these areas, however, and a century later we find it difficult to conclude whether these divergent conservation paths have led to demonstrable differences in population status between galliforms and migratory birds. Compared with species afforded MBTA protection, galliforms are not more likely be listed as imperiled on species status assessments. There is some suggestive evidence, based on BBS data, that galliform populations declined more frequently during the late 20th and early 21st centuries, but these differences appear driven by a single species, Northern Bobwhite, which is better-represented in the BBS dataset, and had the greatest net loss, compared with all other galliforms. Furthermore, galliform abundance did not appear to change in ways that differed consistently from migratory species breeding in the same habitats. While we based these assessments on the best available information, our assessment was hampered by a dearth of large-scale, long-term population data for approximately half of U.S. galliform species.

Even if galliform populations have fared no worse than other birds, there is still ample reason for concern (Rosenberg et al. 2019). Ongoing global change will likely continue affecting the status quo for avian populations, and migratory species will continue to benefit from the broad collaborations, diverse funding mechanisms, and large-scale conservation programs that have evolved over the 100+ years following passage of MBTA. Is galliform monitoring, management, and research poised to follow suit in adapting to these future challenges? The collective focus of conservation efforts for galliforms was historically driven by their popularity as game animals, and there is a striking difference between galliform and waterfowl population trends, which is significant because of the shared management objectives between these two groups related to harvest (Williams et al. 2021). More recently attention on galliforms has shifted to the subset of species with known large-scale population declines (Moss et al. 2010), but many galliform species lack rigorous information on regional- or range-wide population trends. This may be particularly problematic for high-latitude, alpine, and arctic species such as Spruce Grouse, blue grouse (Dendragapus spp.), and ptarmigan, which are under-represented in existing survey data and may be especially vulnerable to future climate change by virtue of the ecosystems they inhabit (Martin and Weibe 2004, Chamberlain et al. 2013).

Thus, we see a two-part challenge to the future of galliform conservation and its ability to address new challenges: barriers to implementing large-scale coordinated efforts, and uneven focus of resources among species based on perceptions of population status sometimes inferred from imperfect data. We find that inter-agency coordination underlies nearly all aspects of effective conservation for migratory birds. To that end, approaches that have been successfully implemented for migratory birds and that could be better emulated for galliforms include:

• (1) Significant support for working groups and technical committees focused on species or species groups. This often includes hiring dedicated coordinators and providing discretionary funding for groups to implement priority projects. For galliforms, such support could help to more consistently address objectives outlined in existing species’ conservation plans, or lead to development and implementation of plans for species that currently lack them.

• (2) Greater scope, scale, and consistency of population monitoring, especially those not adequately captured by existing programs. This has included development of best methodological practices and widespread, standardized data collection (e.g., population surveys and banding) at ecologically relevant scales (both spatial and temporal) for migratory birds. With a few exceptions, comparable programs are lacking for galliforms.

• (3) A standardized and centralized database to facilitate large-scale population assessment and research. The value of comprehensive databases to migratory bird conservation, such as that maintained by the USGS Bird Banding Laboratory, cannot be overstated. No such repository exists for galliforms, and this has likely hampered progress in our understanding of galliform populations and their response to management actions. Greater support for centralized data sharing, and funding for stewards to maintain and improve use, access, and clarity of these data repositories, would be a major step forward.

• (4) Coordinated, data-driven harvest management. The management of waterfowl harvest in North America sets the world-standard for harvest management paradigms. Galliform harvest management would benefit from a thorough review of current practices, and we should consider whether greater interstate cooperation on harvest management practices is necessary for some species.

We see clear evidence of progress towards these areas in recent decades for certain species. For example, the Northern Bobwhite Conservation Initiative (NBCI 2011) has developed a broad-scale coalition of 25 state fish and wildlife agencies, along with federal agencies, non-governmental organizations, and universities, all working towards a unified effort to restore wild populations of Northern Bobwhite (bringbackbobwhites.org). However, even this effort is not without continued challenges to success that could benefit from more closely emulating migratory bird management (Williams et al. 2021). Increasing the breadth of similar grassroots efforts would reflect a major step forward for galliform conservation, particularly if scaled up to cover all species. Current cooperative frameworks exist in a number of entities already focused on galliform management (Supplementary Material Table S2), and formalizing these efforts further in support of the points we list above could prove highly beneficial to the future of galliform conservation.

ACKNOWLEDGMENTS

This research was supported by the USDA National Institute of Food and Agriculture, McIntire-Stennis project no. ME0-41602, through the Maine Agricultural and Forest Experiment Station. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. The findings and conclusions in this article are those of the author(s) and do not necessarily represent the views of the U.S. Fish and Wildlife Service.

Funding statement: Support for P. Schwalenberg was provided by the Alaska Migratory Bird Co-Management Council, through a cooperative agreement with the U.S. Fish & Wildlife Service, Region 7. Support for S. Felege was provided by the Biology Department at the University of North Dakota.

Ethics statement: No birds were handled or observed as part of this research, and the authors adhered to the American Ornithological Society code of professional conduct.

Author contributions: E.J.B., B.E.R., C.J.C., S.N.E-F., D.G., and A.P.M. conceived the idea, design, experiment (supervised research, formulated question or hypothesis). E.J.B., B.E.R., S.N.E-F., and D.G. performed the experiments (collected data, conducted the research). E.J.B., B.E.R., C.J.C., S.N.E-F., D.G., A.P.M., and P.K.S. wrote the paper (or substantially edited the paper). E.J.B., B.E.R., C.J.C., S.N.E-F., D.G., A.P.M., and P.K.S. developed or designed the methods. E.J.B. and B.E.R. analyzed the data. E.J.B., B.E.R., C.J.C., S.N.E-F., D.G., A.P.M., and P.K.S. contributed substantial materials, resources, or funding.

Data availability: No original data were collected for this work.

LITERATURE CITED