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dc.contributor.authorAnnett, Cynthia A.
dc.contributor.authorPierotti, Raymond
dc.identifier.citationAnnett, C. A., & Pierotti, R. (1999). Long-term reproductive output in western gulls: consequences of alternate tactics in diet choice. Ecology, 80(1), 288–297.
dc.description.abstractAbstract. Numerous studies reveal strong, positive skews in long-term breeding performance among free-living animals, yet few studies explore the mechanisms underlying such variation. We examine the results of a 12-yr study of a population of Western Gulls, Larus occidentalis. Of 112 pairs for which we have either long-term ($5 yr) or lifetime reproductive output, 44% bred for only a single year, and an additional 25% bred for only 2–3 yr. A few pairs bred successfully for 6–12 yr and showed higher average clutch size, hatching success, and fledging success within any single season than did less successful breeders. The principal trait influencing both survival and reproduction was individual diet, which consisted of a mix of human refuse and fish. A strong, positive relationship existed among the amount of fish taken, breeding life-span, and reproductive performance. Birds with short life-spans took little or no fish on an annual basis. Birds with breeding lifespans .10 yr and high breeding success took .60% fish. Diet choice was also important for successful recruitment; 90% of banded offspring returning to breed on the colony had parents that had taken predominantly fish. Diets of male, but not female, recruits were correlated with diets of their parents; 90% of male recruits banded as chicks in the colony were successful breeders, in contrast to 10% of other recruits. Despite apparent selective advantages, few recruits take a diet consisting predominantly of fish, which suggests the existence of at least two alternate tactics, i.e., highly risk-prone foraging for fish, or riskaverse foraging for refuse. This suggests that diet choice is passed between generations by means such as learning or cultural transmission from parents to offspring.en_US
dc.description.sponsorshipWe thank the National Park Service for permission to work on Alcatraz. We thank K. Armitage, J. Ellis, T. Good, R. Holt, and T. Peterson for comments on early drafts, and B. Maurer and two anonymous reviewers for comments on a later draften_US
dc.publisherThe Ecological Society of Americaen_US
dc.rightsCopyright by the Ecological Society of America
dc.subjectalternate tacticsen_US
dc.subjectLarus occidentalisen_US
dc.subjectlife historyen_US
dc.subjectWestern Gullen_US
kusw.kuauthorAnnett, Cynthia A.
kusw.kuauthorPierotti, Raymond
kusw.kudepartmentDepartment of Biological Sciencesen_US
kusw.oaversionScholarly/refereed, publisher version
kusw.oapolicyThis item does not meet KU Open Access policy criteria.

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