Energy Invested in Reproduction by Thick-Billed Murres (Uria lomvia)

• Published in: The Auk
• Main Author: Gaston, A. J.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Oxford University Press (OUP) 1985
• Subjects: Arctic; Cepphus grylle; thick-billed murre; Uria lomvia; uria
• Online Access: http://dx.doi.org/10.1093/auk/102.3.447; http://academic.oup.com/auk/article-pdf/102/3/447/30080537/auk0447.pdf

Abstract Pelagic seabirds that lay single-egg clutches have been thought to invest less energy in reproduction than inshore-feeding species that rear more than one young. To examine this idea I calculated time and energy budgets for Thick-billed Murres (Uria lomvia) breeding at two large arctic colonies and compared their energy expenditure with that of a hypothetical group (shirkers) that was capable of feeding at the same rate but did not attempt any reproductive activity. The difference in energy investment between breeders and shirkers was strongly dependent on the average foraging range. I also compared my results with similar estimates for inshore-feeding Black Guillemots (Cepphus grylle). For the two Thick-billed Murre colonies, energy allocated to reproduction represented 30% and 24% of total energy expenditure during the breeding season. These values exceed the estimates for Black Guillemots. The amount of energy invested by Thick-billed Murres at the colonies considered probably is similar to that invested by other seabirds laying larger clutches and rearing heavier young.