The internal organs of four adult, one juvenile and one chick Takahe (Porphyrio [Notornis] mantelli hochstetteri) were dissected, weighed and measured to determine the digestive capacity based on anatomical measurement. Organ dimensions were compared with those of the Pukeko (P. porphyrio melanotus). Because the Takahe were 3 – 4 times larger than the Pukeko, organ weights were scaled by the weight of the femur and length measurements by the length of the femur to enable comparison between the species. The Takahe had significantly deeper beaks, shorter intestines and larger recta than the Pukeko. The pyloric caeca were longer but not significantly so. Although ecological comparisons based on gut morphology are fraught with difficulty, a tentative theory that Takahe may be better at digesting fibre than currently thought is presented.
Potential relationship between meteorological conditions and the timing and path of Cattle Egret migration from colonies in the Hunter Valley (NSW) to locations in Victoria, Tasmania and New Zealand were investigated for the period 1987-1989. Meteorological maps obtained for a period of up to five days previous to known movement dates were analysed to identify possible migration paths. Three potential outward and two potential return paths were identified which make use of wind-flows around high and low systems. The results show that Cattle Egrets may well utilise weather systems in their migration and point to the need for further research for clarification.
The seasonal change in Yellow-eyed Penguin numbers using a landing site (or part of the beach where penguins moved to or from the sea) at Middle Bay, Campbell Island, was monitored between November 1987 and September 1988. Numbers were low during the incubation phase of nesting (November) and rose to a peak during the chick-rearing period (December- March) when most breeding birds were travelling to sea each day. Numbers were low during the moult (April) as most birds were ashore. Peak numbers occurred in May but declined subsequently because of sea lion disturbance and pre-breeding behaviour. A census of 172 landing sites on Campbell Island during May-July 1988 found 1625 penguins, which may have represented a total of 2000 birds, or 490-600 breeding pairs. Decreases in penguin numbers at several landing sites between 1988 and 1990 suggest the population may have declined by about 45%. A census of 115 landing sites on part of the Auckland Islands in November-December 1989 found 934 penguins, which may have represented a population of 420-470 breeding pairs. Allowing for a possible sparse population on the east coast of Auckland Island, 520-570 pairs is a very conservative estimate for the islands. The total Yellow-eyed Penguin population in 1988-1989 was approximately 5930-6970 birds, with at least 56% in the subantarctic.
We assessed the utility of morphometric characters for identifying the sex of adult Fiordland Crested Penguins (Eudyptes pachyrhynchus) on the Open Bay Islands. Penguins that gave ecstatic calls at nest sites during the courtship period were designated as males; their companions at nest sites were designated as females. Measurements of culmen length, foot length and weight showed overlap between sexes, but bill depth and a bill index (culmen length x bill depth) did not. The bill depth and bill index of penguins of unknown sex fell on either side of the zone of non-overlap between sexes. Although the specific criteria for determining sex vary between populations of Fiordland Crested Penguins, measures of bill size appear to be the best criteria in this and other species of penguin.