Publications Archive

A description of the geography and superficial geology of the five islands forming the western chain of the Snares group is given with observations and illustrations of the birds and seals, based on landing on 2 December 1972. Other visits in 1947 and 1964 are noted.

The anatomy of the tongues of five sea birds, the blue petrel (Halobaena caerulea), the grey-backed storm petrel (Garrodia nereis), the black-bellied storm petrel (Fregetta tropica) , the white-capped mollymawk (Diomedea cauta cauta), and the Caspian tern (Hydroprogne caspia) is described and illustrated.

The reliability of sexing and ageing starlings in Canterbury from plumage characters was examined. Males were sexed without error and females almost so (98.7%). Birds in adult plumage were classified as first year or older, and all of known age fell into the correct group.

Features of plumage and behaviour of the soft-plumaged petrel are described and compared with those of other species of Pterodroma, especially P. inexpectata, and Procellaria cinerea, as an aid for further reports of the species at sea.

The occurrence of a white-winged triller (Lalage sueurii) at Macandrew Bay, Otago Peninsula, in February 1969, is documented, being the first record of this species for New Zealand.

The variable oystercatcher (Haematopus unicolor), which has melanistic, pied and intermediate phases, was studied in the field in New Zealand from 1969 to 1972 inclusive. Parents and their progeny were colour-banded, and the development of plumage with age was checked for non-genetic variation. The parent-offspring data can be most simply explained by a genetic model involving a major gene (W) whose dominance is modified only in the heterozygous condition. In the model, the pied condition is homozygous dominant (WW), the melanistic condition is homozygous recessive (ww), and all intermediate-plumaged birds are heterozygous Ww. The wide range of plumage variability in the intermediate phase seems most likely explained by the action of polygenic modifiers acting cumulatively at a number of loci, and specifically on the Ww genotype. Gene frequencies and genotype frequencies are in Hardy-Weinberg equilibrium, indicating that selection does not operate against the heterozygote to form an isolating mechanism between the homozygous pied and melanistic phases. The three phenotypes are therefore best considered as colour phases of one species, H. unicolor.