title: Supplementary diet components of little auk chicks in two contrasting regions on the West Spitsbergen coast.
abstract: The complete diet composition structure of the most numerous planktivorous sea bird, little auk (Alle alle), in the European Arctic, is still not fully recognized. Although regular constituents of little auk chick diets, the copepods,Calanus glacialisandC. finmarchicushave been previously relatively well described, more taxa were frequent ingredients of the bird's meals. Therefore, the role of the little auks supplementary diet components (SDCs) at two colonies in the Svalbard Archipelago, Hornsund and Magdalenefjorden, in 2007-2009, is a main subject of this comparative study. Because the SDCs often consisted of scarce but large zooplankters, this investigation was focused on biomass as a proxy of the SDCs' energy input. Although the total biomass of the food delivered to chicks in both colonies was similar, in Magdalenefjorden, the proportion of SDCs was twice that found in Hornsund. The main SDCs in Hornsund were Decapoda larvae (with predominatingPagurus pubescens) andThysanoessa inermis, whereas the main SDCs in Magdalenefjorden wereC. hyperboreusandApherusa glacialis.Previous investigations, which indicated lipid richness of SDCs, together with our ecological results from the colonies, suggest that this category might play a compensatory role in little auk chick diets. The ability to forage on diverse taxa may help the birds to adapt to ongoing Arctic ecosystem changes.
authors.affiliation: Institute of Oceanology Polish Academy of Sciences, Powstańców Warszawy 55, 81-712 Sopot, Poland.
authors.forename: Rafał
authors.initials: R
authors.lastname: Boehnke
authors.affiliation: Institute of Oceanology Polish Academy of Sciences, Powstańców Warszawy 55, 81-712 Sopot, Poland.
authors.forename: Marta
authors.initials: M
authors.lastname: Gluchowska
authors.affiliation: Department of Vertebrate Ecology and Zoology, University of Gdańsk, Wita Stwosza 59, 80-308 Gdańsk, Poland.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Wojczulanis-Jakubas
authors.affiliation: Department of Vertebrate Ecology and Zoology, University of Gdańsk, Wita Stwosza 59, 80-308 Gdańsk, Poland.
authors.forename: Dariusz
authors.initials: D
authors.lastname: Jakubas
authors.affiliation: Department of Biology, Pomona College, 175 W. 6th St., Claremont, CA 91711 USA.
authors.forename: Nina J
authors.initials: NJ
authors.lastname: Karnovsky
authors.affiliation: Institute of Oceanology Polish Academy of Sciences, Powstańców Warszawy 55, 81-712 Sopot, Poland ; Freshwater Institute, Fisheries and Oceans Canada, 501 University Crescent, Winnipeg, MB R3T 2N6 Canada.
authors.forename: Wojciech
authors.initials: W
authors.lastname: Walkusz
authors.affiliation: Institute of Oceanology Polish Academy of Sciences, Powstańców Warszawy 55, 81-712 Sopot, Poland.
authors.forename: Slawomir
authors.initials: S
authors.lastname: Kwasniewski
authors.affiliation: Institute of Oceanology Polish Academy of Sciences, Powstańców Warszawy 55, 81-712 Sopot, Poland.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Błachowiak-Samołyk
keywords: Arctic; Climate change; Feeding ecology; Little auk; Svalbard; Zooplankton