diet

Feral cats became established on Raoul Island some time between 1836 and 1872; the prey available to them included a great variety of nesting seabirds, few of which are present now, landbirds and kiore (Rattus exulans). Norway rats reached the island in 1921, providing additional prey for cats, but also another potential predator of seabirds. The diet of cats is described from guts and scats collected between 1972 and 1980. Rats are the main food, with land birds second in importance, and seabirds are now a minor item.

Fallow deer did not prefer either of the two main canopy species (silver beech, Nothofagus menziesii, and radiata pine, Pinus radiata), or any of the common indigenous shrubs, ferns, herbs and monocotyledons in three habitat types (beech, shrub-hardwood, and exotic forest). They did prefer all the common sub canopy tree species, and these comprised the bulk of diet in all habitats. Broadleaf (Griselinia littoralis) was the most important single food, with litterfall being its dominant source.

The foraging behaviour, diet and habitat use of North Island kokako (Callaeas cinerea wilsoni) were studied in Puketi State Forest from October 1981 to August 1982. Kokako fed mainly from branches and twigs of canopy and upper-understorey plants. Although 68 different foods were eaten, only eight contributed more than 5% to the observed diet in any season. The diet consisted of fruit (44%), unknown foods (18%), leaves (15%), epiphytes (11%), invertebrates (8%), buds (2%), flowers (l%) and nectar (1%). The use of these food- types varied seasonally.

Feral goats (Capra hircus) have been hunted intensively every year since 1972 on the 2950 ha Raoul Island to protect the indigenous vegetation. Rumen samples taken from 103 goats shot in 1982-83 showed that a minimum of 48 species of vascular plants, mostly indigenous species, were eaten. Only seven foods—Metrosideros kermadecensis, Coriaria arborea var. kermadecensis, Me/icytus ramiflorus spp. ramiflorus, Rhopalostylis baueri var.

The introduced brushtail possum (Trichosurus vulpecula) is a major environmental and agricultural pest in New Zealand but little information is available on the ecology of possums in drylands, which cover c. 19% of the country. Here, we describe a temporal snapshot of the diet and feeding preferences of possums in a dryland habitat in New Zealand's South Island, as well as movement patterns and survival rates. We also briefly explore spatial patterns in capture rates. We trapped 279 possums at an average capture rate of 9 possums per 100 trap nights.

The diet and food preferences of the kererū (Hemiphaga novaeseelandiae) were studied in Whirinaki Forest Park, central North Island, New Zealand, during February 2000 – March 2001. The study was carried out in two areas of podocarp–hardwood forest, Oriuwaka (1750 ha) and Otupaka (1830 ha). Fruit dominated in the diet at both sites (65% in Oriuwaka, 87% in Otupaka), but there were seasonal changes. Foliage and flowers were more important in the diet in winter and spring, but the timing of the switch from fruit to foliage differed between the areas.

Browsing by introduced brushtail possums is linked to major declines in mistletoe abundance in New Zealand, yet in some areas mistletoes persist, apparently unaffected by the presence of possums. To determine the cause of this spatial variation in impact I investigated the abundance and condition (crown dieback and extent of possum browse) of two mistletoes (Alepis flavida, Peraxilla tetrapetala) and abundance and diet of possums in two mountain beech (Nothofagus solandri var. cliffortioides) forests in the central-eastern South Island of New Zealand.

Ratites (ostriches Struthio camelus) and ungulates (red deer Cervus elaphus scoticus and goats Capra hircus) were presented with 14 indigenous shrubs in cafeteria-style trials. The shrubs represented the spectrum of woody plant architecture, ranging from broadleaved monopodial species through to small-leaved highly branched divaricates. Trials were stopped when almost all shoots of the plant expected to be most preferred had been consumed. There were considerable differences between the herbivores in their selection of certain plant species.