MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 352:221-234 (2007) - DOI: https://doi.org/10.3354/meps07078 Seabirds as indicators of marine food supplies: Cairns revisited John F. Piatt1,*, Ann M. A. Harding1,2, Michael Shultz1, Suzann G. Speckman3, Thomas I. van Pelt1, Gary S. Drew1, Arthur B. Kettle4 1US Geological Service Alaska Science Center, 1011 E. Tudor Rd., Anchorage, Alaska 99503, USA 2Alaska Pacific University, Environmental Science Department, 4101 University Dr., Anchorage, Alaska 99508, USA 3School of Aquatic and Fishery Sciences, University of Washington, 1122 NE Boat St., Seattle, Washington 98105, USA 4Alaska Maritime National Wildlife Refuge, US Fish and Wildlife Service, 2355 Kachemak Bay Dr., Homer, Alaska 99603, USA *Email: john_piatt@usgs.gov ABSTRACT: In his seminal paper about using seabirds as indicators of marine food supplies, Cairns (1987, Biol Oceanogr 5:261271) predicted that (1) parameters of seabird biology and behavior would vary in curvilinear fashion with changes in food supply, (2) the threshold of prey density over which birds responded would be different for each parameter, and (3) different seabird species would respond differently to variation in food availability depending on foraging behavior and ability to adjust time budgets. We tested these predictions using data collected at colonies of common murre Uria aalge and black-legged kittiwake Rissa tridactyla in Cook Inlet, Alaska. (1) Of 22 seabird responses fitted with linear and non-linear functions, 16 responses exhibited significant curvilinear shapes, and Akaikes information criterion (AIC) analysis indicated that curvilinear functions provided the best-fitting model for 12 of those. (2) However, there were few differences among parameters in their threshold to prey density, presumably because most responses ultimately depend upon a single threshold for prey acquisition at sea. (3) There were similarities and some differences in how species responded to variability in prey density. Both murres and kittiwakes minimized variability (CV < 15%) in their own body condition and growth of chicks in the face of high annual variability (CV = 69%) in local prey density. Whereas kittiwake breeding success (CV = 63%, r2 = 0.89) reflected prey variability, murre breeding success did not (CV = 29%, r2 < 0.00). It appears that murres were able to buffer breeding success by reallocating discretionary loafing time to foraging effort in response (r2 = 0.64) to declining prey density. Kittiwakes had little or no discretionary time, so fledging success was a more direct function of local prey density. Implications of these results for using seabirds as indicators are discussed. KEY WORDS: Ecological indicators · Seabirds · Food availability · Threshold · Functional response · Predatorprey dynamics Full text in pdf format PreviousNextCite this article as: Piatt JF, Harding AMA, Shultz M, Speckman SG, van Pelt TI, Drew GS, Kettle AB (2007) Seabirds as indicators of marine food supplies: Cairns revisited. Mar Ecol Prog Ser 352:221-234. https://doi.org/10.3354/meps07078 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 352. Online publication date: December 20, 2007 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2007 Inter-Research.