Diets of yellow-eyed, fiordland crested, and little blue penguins breeding sympatrically on codfish Island, New Zealand

Abstract

Diets of sympatrically breeding yelloweyed (Megadyptes antipodes), fiordland crested (Eudyptespachyrhynchus), and little blue penguins (Eudyptula minor) were examined over 1 week in late October on Codfish Island, New Zealand to determine the degree of dietary overlap. Diets of yellow-eyed (YEP’s) and fiordland crested (FCP’s), and yellow-eyed and little blue penguins (LBP’s) overlapped by 18% and 17%, respectively; LBP and FCP’s by 46%. YEP’s ate 7 species (out of a total of 16) that were not eaten by FCP’s or LBP’s, 2 of which comprised 97% of the diet by weight, and 6 of which are demersal in habit. YEP’s mainly ate fewer large individuals, whereas FCP’s and LBP’s ate large numbers of small prey items. All species eaten by FCP’s and LBP’s were small juvenile forms that are found in the macrozooplankton, indicating foraging by FCP’s and LBP’s was exclusively pelagic; YEP’s foraged demersally as well as pelagically. This observation agrees with what is known of the foraging behaviour of mainland populations where sympatry does not occur. © Crown 1990.