Diet composition of Emperor Penguin chicks Aptenodytes forsten‘ at two Mawson Coast colonies, Antarctica

• Published in: Ibis
• Main Authors: ROBERTSON, GRAHAM, WILLIAMS, R., GREEN, KEN, ROBERTSON, LYNNE
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2008
• Subjects: Taylor Glacier; Mawson Station; Auster; Mawson Coast; Antarc*; Antarctica; antarcticus; Aptenodytes forsteri
• Online Access: https://oceanrep.geomar.de/id/eprint/37717/; https://oceanrep.geomar.de/id/eprint/37717/1/2573.pdf; https://doi.org/10.1111/j.1474-919X.1994.tb08127.x

The diet composition of Emperor Penguin Aptenodytes forsteri chicks was examined at Auster and Taylor Glacier colonies, near Australia's Mawson station, Antarctica, between hatching in mid-winter and fledging in mid-summer by “water-offloading” adults. Chicks at both colonies were fed a similar suite of prey species. Crustaceans occurred in 82% of stomach samples at Auster and 87% of stomachs at Taylor Glacier and were heavily digested: their contribution to food mass could not be quantified. Fish, primarily bentho-pelagic species, accounted for 52% by number and 55% by mass of chick diet at Auster, and squid formed the remainder. At Taylor Glacier the corresponding values were 27% by number and 31% by mass of fish and 73% by number and 69% by mass of squid. Of the 33 species or taxa identified, the fish Trematomus eulepidotus and the squid Psychroteuthis glacialis and Allu-roteuthis antarcticus accounted for 64% and 74% of the diets by mass at Auster and Taylor Glacier, respectively. The sizes of fish varied temporally but not in a linear manner from winter to summer. Adult penguins captured fish ranging in length from 60 mm (Pfeura-gramma antarcticum) to 250 mm (T. eulepidotus) and squid (P. glacialis) from 19 to 280 mm in mantle length. The length-frequency distribution of P. glacialis showed seasonal variation, with the size of squid increasing from winter to summer. The energy density of chick diet mix increased significantly prior to “fledging”.