Publications Archive

Pellet casting was studied in a population of South Island robins (Petroica australis australis) at Kowhai Bush, Kaikoura from April 1977 to July 1978. Pellet regurgitation is described. Casting has a diurnal rhythm. Monthly regurgitation rates reflected the diet of the robins, with the highest rates occurring in the summer months when the main food is berries and invertebrates with their indigestible seeds and exoskeletons. It was calculated that, during February 1978, the month of highest mean egestion rate, a Robin would egest six pellets per day. The effect of age and sex on the frequency of castings is discussed.

Letter to the Editor, 13 June 1979

The feeding ecology of the Wrybill (Anarhynchus frontalis) was compared between two sites – a flood-prone riverbed and a stable riverbed. Larvae of aquatic insects, particularly mayfly (Deleatidium spp.), were the main prey of Wrybills, which captured them by a variety of methods. The sideways-bent bill was useful in capturing insects from the under-surface of stones where they would normally have been inaccessible to birds with shorter, straight, or even up-curved bills. The evolutionary significance of the bent bill is discussed with reference to climatic trends during and since the Pleistocene period. During floods, aquatic prey was relatively unavailable to Wrybills, causing them to switch to riparian foraging.

Stationary and walking counting methods to obtain numbers of bird species in survey work were compared under Tasmanian forest conditions. For short observation times, the stationary method was clearly inferior to walking at a brisk pace through the survey area. In unsheltered areas, windy conditions significantly reduced the number of species recorded compared with calm conditions in either fine or rainy weather. When time is short, a basic 10-minute walking unit will yield a reasonable percentage of the number of species present.

Recent observations and counts of chicks suggest that predation by rats and cats may be destroying the Sooty Tern (Sterna fuscata) colony at Denham Bay, Raoul Island. Aspects of this predation and of a comparable situation on Ascension Island are discussed. More management-oriented research is needed on the Sooty Tern at Raoul Island, and an annual assessment of breeding success and population trends is proposed.

A survey of the distribution of South Island fernbirds (Bowdleria punctata punctata) in relation to vegetation types was made in part of the Kongahu Swamp, Karamea district, West Nelson. The data show that fernbirds have a marked preference for areas with low, dense ground vegetation and emergent shrubbery, and are infrequently seen in cut-over kahikatea forest bordering on swampland, or in level pakihi vegetation lacking shrubs. Observations on fernbird habitat at other places are compared with those for Kongahu Swamp.

Dr Pat Vickers Rich. Bulletin 184. Bureau of Natural Resources, Geology and Geophysics. Canberra 1979.

During 1978, Fiji experienced a minor invasion of Australian pelicans (Pelecanus conspicillatus). a species not recorded there previously.