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J. Mark Hipfner, The Effects of Parental Quality and Timing of Breeding on the Growth of Nestling Thick-Billed Murres, The Condor: Ornithological Applications, Volume 99, Issue 2, 1 May 1997, Pages 353–360, https://doi.org/10.2307/1369941
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Abstract
In the Thick-billed Murre Uria lomvia, an Arctic seabird that raises a single chick annually, late-hatched chicks often grow slowly and depart the nest lighter in mass than early-hatched chicks. At Coats Island, N.W.T., Canada, in 1994 and 1995, I examined whether the seasonal declines in growth were caused by timing of breeding (the "seasonal deterioration" hypothesis), or by late breeding of less capable pairs (the "parent quality" hypothesis). I removed the single egg from early-breeding pairs, inducing them to relay, and compared the growth of chicks from these replacement eggs to that of chicks of unmanipulated pairs. Growth rate and mass at nest departure correlated negatively with hatching date in the general population. However, in both years the experimental chicks grew as well as the chicks of unmanipulated early-breeding birds, and departed at similar mass. The experimental chicks also grew more quickly than unmanipulated chicks that hatched later in the season, in one of two years. These results support the parent quality hypothesis, but not the seasonal deterioration hypothesis. I suggest that the late breeding of less capable birds is the likely proximate cause of many of the seasonal declines in success reported frequently in the Alcidae.
