CORE Metadata, citation and similar papers at core.ac.uk Provided by Digital.CSIC Diet segregation between two colonies of little penguins Eudyptula minor in southeast Australia 1 2 3 ANDRÉ CHIARADIA, * MANUELA G. FORERO, KEITH A. HOBSON, 4 1,5 1 1 STEPHEN E. SWEARER, FIONA HUME, LEANNE RENWICK AND PETER DANN 1Research Department, Phillip Island Nature Parks, PO Box 97, Cowes,Vic. 3922, Australia (Email:
[email protected]); 2Departamento de Biología de la Conser vación, Estación Biológica de Doñana, Avda Américo Vespucio, Sevilla, Spain; 3Environment Canada, Saskatoon, Saskatchewan, Canada; 4Department of Zoology, University of Melbourne, Melbourne,Victoria, and 5Private Bag 10, New Norfolk, Tasmania, Australia Abstract We studied foraging segregation between two different sized colonies of little penguins Eudyptula minor with overlapping foraging areas in pre-laying and incubation. We used stomach contents and stable isotope measurements of nitrogen (d15N) and carbon (d13C) in blood to examine differences in trophic position, prey-size and nutritional values between the two colonies. Diet of little penguins at St Kilda (small colony) relied heavily on anchovy while at Phillip Island (large colony), the diet was more diverse and anchovies were larger than those consumed by St Kilda penguins. Higher d15N values at St Kilda, differences in d13C values and the prey composition provided further evidence of diet segregation between colonies. Penguins from each colony took anchovies from different cohorts and probably different stocks, although these sites are only 70 km apart. Differences in diet were not reflected in protein levels in the blood of penguins, suggesting that variation in prey between colonies was not related to differences in nutritional value of the diet.