Publications Archive

In a 1-day study of the Australian Coot (Fulica atra australis), the duration of dives increased with increasing depth, although the frequency of diving remained relatively constant. Duration and frequency of dives at given depths appeared not to vary with age. However, aggressive adults often drove young birds into deeper water. The duration of dives changed with the time of day, the birds preferring to dive in direct sunlight.

In 1991, 4780 km of coast of New Zealand were patrolled and 6955 dead seabirds were found as pan of the Beach Patrol Scheme. An unusual find was a Red-tailed Tropicbird (Phaethon rubricauda), and more than usual were found of the Antarctic Petrel (Thalassoica antarctica), White-headed Petrel (Pterodroma lessonii), Little Black Shag (Phalacrocorax sulcirostris) and Brown Skua (Catharacta skua lonnbergi). A summary is given of the coastal and monthly distributions of Morus and Sula species found during the 1943-1991 period. Overall, 5637 Australasian Gannets (Morus serrator) were found, mainly on beaches of the northern half of the North Island. The peak period of adult recoveries was in December-February, but that of juveniles was in February-May. Both the Brown Booby (Sula leucogaster) and the Masked Booby (Sula dactylatra) are vagrants to the New Zealand mainland, with four and one individuals respectively having been found by patrollers.

G.R. Gray first used the name Pelecanus serrator in association with the drawing by Sydney Parkinson of an adult Australasian Gannet taken at sea near the Three Kings Islands in 1769. Parkinson’s drawing is an illustration of the specimen described in manuscript by Daniel Solander as Pelecanus serrator. Both the drawing and the description are of the type specimen and have previously unrecognised taxonomic importance. The correct type locality of Morus serrator is the vicinity of the Three Kings Islands.

The Kakerori, or Rarotonga Flycatcher, of the Cook Islands has two distinctive colour forms: orange and grey. Our colour-band study showed that colour is simply related to age, not to sex as described earlier. When fledglings leave the nest their body is covered in grey down, and their wings and tail are still growing. Orange juvenal plumage is attained about one month after fledging. Despite having similar orange plumage, yearlings can be distinguished from 2 year-old birds on the basis of bill colour and wing and tail lengths. Third-year birds have elements of both main colour phases. Once the definitive basic plumage is attained in the fourth year, the age of grey birds cannot be determined. Wing and tail lengths apparently increase at each successive moult until the definitive basic plumage is reached. Males are larger than females, with bill length being the best discriminator. The progressive colour change recorded here parallels that described for three of the four other species of Pomarea flycatcher in eastern Polynesia, but colour variation in the other species, and in some other monarch flycatchers in the Pacific, needs critical examination. The ability to distinguish three cohorts of Kakerori is useful in measuring annual variations in productivity, survivorship, and age structure of the population.

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.