Diet of the Fiordland Crested penguin (Eudyptes pachynchus) during the chick rearing season : A dissertation submitted in partial fulfilment of the requirements for the Degree of Master of Applied Science in Lincoln University

Abstract

This study investigated the foods fed to Tawaki chicks during the guard and postguard phases of the breeding cycle. Fieldwork was carried out at Jackson Head and Codfish Island in 1995 and 1996. Tawaki populations have apparently been declining on both the mainland and on offshore islands. Populations in the southern parts of the range are apparently erratic in their distribution and numbers compared with the northern populations. As both mainland and island populations are thought to be affected similarly it is possible that these declines may be related to food. Stomach content samples were collected using a slightly modified water offloading technique. Theses were then analysed to determine diet composition. Previously unrecorded prey types( Galaxias maculatas, G. brevipinnis, G. fascia/us) were recovered from stomach content samples. Differences in diet between breeding phases and study sites were possibly a result of differences in the timing of the life history cycle of the prey type and the geographical distribution of prey. Fish appeared to be the most important prey type fed to chicks at both study sites. Cephalopods were present in constant but low amounts and crustaceans (ie Ommatocarnicus macgillveryi) varied widely in terms of numbers and weight, between breeding season, phase and study site. Tawaki probably forage over the continental shelf as prey types identified were mainly components of the continental shelf macrozooplankton.