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Since the European discovery of the Auckland Islands, at least ten species of land mammals have been introduced there. Most arrived in the first half of the ninteenth century during periods of exploitation by sealers and whalers, followed by short-lived Māori and European settlements at Port Ross. Several species required multiple introductions before becoming established. For those populations that naturalised, cattle (Bos taurus) occupied Enderby Island and were eradicated by 1993, goats (Capra aegagrus hircus) remained restricted to the northern end of Auckland Island and were eradicated by 1991, while pigs (Sus scrofa) spread across the entire Auckland Island and remain there today. Rabbits (Oryctolagus cuniculus) established on Rose and Enderby Islands, and were eradicated in 1993. Cats (Felis catus) and mice (Mus musculus domesticus) were both first recorded in 1840 on Auckland Island and remain there today. Rats (Rattus spp.) have never established on the Auckland Islands. Collectively, cattle, goats, sheep (Ovis aries), pigs, and rabbits transformed habitats and altered ecosystem processes, and suppressed tussock, megaherbs, and woody vegetation on Auckland, Enderby, Rose, Ewing, and Ocean Islands. Cats and pigs are together responsible for the extirpation or major reduction of surface-nesting and burrowing seabird colonies, and ground-nesting land birds from Auckland Island. Before dying out on Enderby Island, pigs had similar impacts there. Mice have altered invertebrate community composition and are likely responsible for lower abundancies of wētā (Dendroplectron aucklandense) and large weevils (Curculionidae) on Auckland Island. Disappointment Island remained free of introduced mammals, while on Adams Island they had only fleeting and minimal impact. Humans also had direct impacts on birds through hunting for consumption, with large surface-nesting seabirds severely affected around Port Ross. The Auckland Island merganser (Mergus australis) was driven to extinction by presumed mammal predation and well-documented museum collecting. Eradication of pigs, cats, and mice from Auckland Island and Masked Island (Carnley Harbour) would remove the last introduced mammals from the New Zealand subantarctic region.

Australasian little grebe (Tachybaptus novaehollandiae) was detected at the Whangarei sewerage wetlands at Kioreroa Road, in September–October 1996, and since 2012 has attempted to breed. Between October 2015 and April 2017, a pair of grebes produced 4 fledglings from 5 nesting attempts. Adults fed chicks for 26–29 days by diving in open areas with swamp lily (Ottelia avalifolia). Fledglings began independent foraging between 19 and 26 days old. Fledglings were not seen at the site after reaching c. 55-days old. The young from late clutches left the natal site in March–April, 3 weeks after their parents were last detected there. The site was not used by any grebes in June and July.

Face, wing, bill, and leg characteristics of grey ducks (Anas. s. superciliosa), of captive-raised F1 and backcrossed grey duck x mallard (A. platyrhynchos) hybrids, and of wild “grey-like” and “mallard-like” ducks in New Zealand were evaluated to assist recognition of grey duck x mallard hybrids in the field. Face pattern was the single character best able to discriminate grey ducks from all others, most grey-like hybrids from all mallard-like hybrids, but not most F1 and backcrossed mallard hybrids from mallards. Upper wing pattern, and bill and leg colours assisted discrimination alongside face pattern but not so on their own. The extensive phenotypic variability now apparent within the combined grey duck – mallard population in New Zealand restricts consistent discrimination to 3 “taxa”: grey ducks, grey-like ducks (“grallard/greylard”), and mallard-like ducks (“New Zealand mallard”).

Data on the effects of aerial 1080 operations on non-target bird species in New Zealand are scarce and largely limited to short-term colour-banding or radio-tracking studies, or standardised call counts. During a 22-year study in Tongariro Forest, all 142 radio-tagged North Island brown kiwi (Apteryx mantelli) survived 4 landscape-scale (20,000 ha) aerial broadcast 1080 operations targeting brush-tailed possum (Trichosurus vulpecula) and rats (Rattus spp.). Furthermore, both kiwi chick survival to 6 months old and New Zealand fantail (Rhipidura fuliginosa) nesting success were significantly higher in the first 2 breeding seasons following the use of 1080 poison than in subsequent years of the 5-year cycle. We observed several episodes of ferret (Mustela furo) killing multiple adult kiwi, particularly in the last half of the 1080 cycle. Population modelling showed that a 5-year 1080 operation cycle resulted in population gains for 2 years, followed by declines in the remaining 3 years that largely negated these benefits. Our data thus support the shift to a 3-year 1080 operation cycle which will more likely result in this kiwi population growing at close to the 2% per year target set by the 2018–2028 Kiwi Recovery Plan.