Behavioral Ecology Vol. 15 No. 2: 332-337
Behavioral Ecology vol. 15 no. 2 © International Society for Behavioral Ecology 2004; all rights reserved
Natural variation in the sexually selected feather ornaments of crested auklets (Aethia cristatella) does not predict future survival
a Department of Biology, Memorial University of Newfoundland, St. John's, Newfoundland A1B 3X9, Canada b Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK c Canadian Wildlife Service, 6 Bruce St., Mount Pearl, Newfoundland A1N 4T3, Canada d Department of Biology, Lumbars Building, York University, 4700 Keele St., Toronto, Ontario M3J 1P3, Canada
Address correspondence to I. L. Jones. E-mail: ijones{at}morgan.ucs.mun.ca.
We evaluated whether sexually selected crest and auricular plume feather ornaments of crested auklet (Aethia cristatella) adults covaried with individual local survival over 11 years (1991–2001). Crested auklets (n = 364 total) were captured near breeding sites, marked with color rings, and local survival estimates were based on color ring resightings at a breeding colony. Survival estimates and relationships among local survival and crest length, auricular plume length, mass and tarsus were evaluated using the program MARK. The best models included four groups, defined by sex and ease of resighting, that differed in resighting rate (p) but not local survival rate (
). This model structure effectively explained sources of variation in local survival and resightability among individuals. The best fitting model showed local survival rate varying annually, while accounting for differences in resightability of marked individuals between the sexes and groups ([t], p[sex*ease of resighting]). Annual local survival varied from 0.940 ± 0.029 (SE) in 1993–1994 to 0.767 ± 0.034 in 1997–1998 and averaged 0.859 ± 0.019. We found no evidence that crested auklet local survival covaried with continuous variation in individuals' ornaments. Simulations indicated that our data set was sufficient to detect a relationship between local survival and a covariate that equaled or exceeded a range of 8%. The implications for competing sexual selection mechanisms of empirically measured survival–ornament relationships are controversial, but our study emphasizes that survival estimates for such investigations must control for confounding factors such as resighting rate as well as have sufficient statistical power and time scale to be biologically meaningful. Our results are most consistent with the idea that the conspicuous variation in crested auklet's showy ornaments is arbitrary with respect to individual viability as quantified by their long-term survival.
Key words: Aethia cristatella, crested auklets, feather ornaments, mark-recapture, sexual selection, survival, viability indicators.