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Chinstrap Penguin
Little Penguin
Megadyptes antipodes C. Michael Hogan PhD April 6, 2009 This endangered species is the rarest of all penguins, with an estimated population of fewer than 1600 breeding pairs. Endemic to certain of New Zealand coasts and islands, this bird's viability is limited by the quality and quantity of its terrestrial breeding habitat. Approximately 1000 AD, the Maori people arrived from Polynesia and burnt large areas of forest in order to kill a variety of birds; European settlers from the 1800s aggravated the habitat loss by further forest clearing and the introduction of widespread livestock grazing. DISTRIBUTION M. Antipodes occurs on New Zealand's South Island from Cape Wanbrow at Oamaru and the Otago Peninsula to the Catlins and southern tip of South Island in Foveaux Strait; on the Otago Peninsula a noteworthy habitation site is above Pipikaretu Beach. The species is also found on several major islands under New Zealand national control including Stewart Island, Campbell Island and the Auckland Islands. Within the Catlins one location of regular habitation is Curio Bay. On the Stewart Island group, 79 pairs were counted on Stewart Island, while 61 pairs were observed on the much smaller Codfish Island. (Massaro. 2003) Other islands within the Stewart group on which Yellow-eyed Penguins were found include Tommy Island, Crayfish Island, Ulva Island, Bench Island, Weka Island, Noble and Anchorage Islands. On Stewart Island habitation sites include Rollers Beach, Port Pegasus and Golden Beach. Campbell Island exhibits a particularly regular location for M. antipodes at Capstan bay. Within the Auckland Island group, the species is found throughout, with particularly robust habitation on Enderby and Rose Islands. M. antipodes occurs on Marion Island within the Prince Edward Islands in the sub-antarctic Indian Ocean. Finally the yellow-eyed penguin has been documented on Macquarie Island. TAXONOMY The species was first described in 1841 by Jacques Bernard Hombron and Honoré Jacquinot. M. antipodes is the only extant member of its genus, M. waitaha being a recent extinction. The sub-antarctic populations of M. antipodes developed subsequent to the M. waitaha extinction. The genus Megadyptes diverged from the kindred genus Eudyptes approximately 15 million years ago. (A.J. Baker et al., 2006) MORPHOLOGY The species name derives from a band of bright yellow extending from the eyes to the back of the head. The bird's head is pale yellow head with even paler yellow iris; black feather shafts emanate from the head. Juveniles manifest a gray head absent of the yellow stripe until age one; juvenile irises are gray. M. antipodes attains a length of 75 cm with body mass slightly over six kg. Both throat and chin are brownish-black.
DIET AND BEHAVIOUR The Yellow-eyed Penguin has a diet of roughly nine tenths fish and the balance of cephalopods, notably arrow squid (Nototodarus sloanii) Fish species taken include cod (Pseudophycis bachus and Parapercis colias), opalfish (Hemerocoetes monopterygius), and New Zealand blueback sprat (Sprattus antipodum). M. antipodes swims six to 13 km out to sea in search of seafood. They typically depart from their nesting areas at daybreak and return the same evening during chick rearing, although they commonly stay several days in the ocean when chicks are independent. Typical depths realised are 25 to 55 metres. BREEDING Male and female M. antipodes arrive on beaches, with re-unification of mates or courtship; this species is monogamous and couples return to the same beach as the last breeding season. Nests are typically in the form of burrows within semi-sandy soil, amid a habitat of coastal scrub or forest. The M. antipodes pair typically seeks out a relatively private nesting location, out of sight of other penguins; thus, this species is not considered colonial in the sense of the Magellanic Penguin or other penguins that form large colonies of dense habitation. (Hogan, 2008) Common cover plants are Phormium tenax, Coprosma repens and Pittosporum tenuifolium, on ocean-facing slopes and ravines. Each parent participates in incubation and brooding, with fledging of the chicks occurring in March. At that time each adult fattens itself by about two kg with intensive feeding, since moulting will ensue, when no ocean entry is feasible for approximately 21 days, due to the unseaworthy moulting coat. CONSERVATION This penguin is endangered, with principal ongoing threat being coastal deforestation and overgrazing of livestock. Overfishing of its food sources in the Southern Pacific Ocean is a parallel threat. Concomitant threats are introduced terrestrial predators such as stoats and domestic cats. An additional mortality factor was identified in 2002 as a pathogenic disease known as Diphtheritic stomatitis, which is induced by Corynebacterium amycolatum, postulated to be driven by a primary viral attack. (Icon Group. 2008) REFERENCES * Melanie Massaro and David Blair. 2003. Comparison of population numbers of yellow-eyed penguins, Megadyptes antipodes, on Stewart Island and on adjacent cat-free islands, New Zealand Journal of Ecology, vol. 27, no. 2 * A.J. Baker, S.L. Pereira, O.P. Haddrath and K.A. Edge. 2006. Multiple gene evidence for expansion of extant penguins out of Antarctica due to global cooling. Proc Biol Sci. 273 (1582): 11–17 * Icon Group International, Inc. 2008. Bacteriologists, published by ICON Group International, Inc., 214 pages ISBN 0546682103 * C. Michael Hogan. 2008. [http://globaltwitcher.auderis.se/artspec_information.asp?thingid=232 Magellanic Penguin, GlobalTwitcher.com, ed. N. Stromberg] |
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