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The incidence of predation on house sparrows (Passer domesticus) and hedge sparrows (Prunella modularis) by captive brushtail possums (Trichosurus vulpecula), and the bird tissues consumed following predation, were recorded over 26 weeks in a facility where possums were housed in single sex groups. A total of 44 sparrow carcasses was recovered; on average 1.7 birds were killed per week (range 0-9 sparrows per week) in pens that each housed 8-12 possums. Tissue was eaten from fewer than half (48 %) of the birds killed. There were no significant differences in the incidences with which different tissues (brain, breast, legs, or viscera) were eaten. This study corroborates observations of bird predation by possums in the wild. Importantly, it shows that a high proportion of birds killed by possums are not eaten.

We compared the behaviour, energy expenditure, and food intake of male and female South Island pied oystercatchers, Haematopus ostralegus finschi, breeding in pasture and crop paddocks in Canterbury. In this monogamous species, females spent more time inactive than males (P=0.03) and there was a trend for males to spend more time in territory defence than females (P=O.O8). There were no significant differences in other behaviours and the sexes did not differ in their food intake rates. We used literature values for this species to estimate the energy expended in each activity and the energy expenditure rate over the breeding season. Despite the differences in the proportion of time spent in territory defence and inactivity by the sexes, males had a lower rate of energy expenditure than females over the breeding season (P=0.07). We suggest that behavioural differences are unlikely to compensate female South Island pied oystercatchers for their costs of gamete production and the difference in energy expenditure may reflect the uncertainty of paternity of males.

Nesting pairs of brown skuas (Catharacta lonnbergi), black-backed gulls (Larus dominicanus), red-billed gulls (Larus novaehollandiae), white-fronted terns (Sterna striata), Chatham Island oystercatchers (Haematopus chathamensis) and shore plovers (Thinornis novaeseelandiae) were counted during 10 seasons on Rangatira (South East) and Mangere islands of the Chatham Islands. It was concluded that the small numbers of skuas, oystercatchers, and shore plovers on the islands was a result of habitat shortage, but that populations of the colonially-breeding gull and tern were constrained by food limitation in the surrounding seas. Whereas skuas, black-backed gulls, and terns nested in the open with conspicuous nests the other shore species on the islands had concealed nests. Comparison with nesting on Chatham Island, the New Zealand mainland, and subantarctic islands suggested that concealed nesting by red-billed gulls, oystercatchers and shore plovers was most likely in response to the presence on the islands of the predacious brown skua.

Brown teal (Anas chlorotis) populations at Clendon Cove and Tutaematai in Northland, New Zealand, declined catastrophically between 1993 and 1995, from 31 pairs to 1 and from 22 pairs to 8, respectively. Mean productivity was 1.8 fledglings pair1 in both populations. Fledgling survival was almost nil with only 1 of 51 identifiable fledglings surviving to recruit into 1 population. Almost all fledgling mortality occurred within 3 months of independence. Annual adult survival was 15% at Clendon Cove and 43% at Tutaematai and most deaths occurred in October-December, immediately after breeding. At Clendon Cove, significant mortality also occurred in autumn. Destruction of breeding and refuge habitat by cattle seeking moisture during periods of drought was identified as a significant cause of decline.