Genetic introgression from Chatham Island Red-crowned parakeet (Cyanoramphus novaezelandiae chathamensis) is a long-standing problem in the conservation of the rare Forbes' parakeet (C. forbesi) on Mangere Island, New Zealand. Microsatellite genotypes, mitochondrial DNA sequences, and morphological markers have been applied to study the situation. An extensive history of hybridisation was detected in the single remaining Forbes' parakeet population, where no less than 81% of all birds screened are considered hybrids. Genetic markers showed that a large proportion of birds identified as Forbes' parakeets by crown plumage are cryptic hybrids. Only a small proportion of birds with Forbes' parakeet morphotype were found to be genetically distinct from Chatham Island Red-crowned parakeets using microsatellite and mitochondrial DNA assignment tests, but these still represent an Evolutionarily Significant Unit (ESU) for conservation.

Magenta Petrels Pterodroma magentae were caught at light‐attraction stations on southwest Chatham Island, New Zealand, and most were fitted with transmitters. Of 52 captured since 1993, 71% were males, and all 36 tracked adequately proved to be non‐breeders in the breeding season of capture. Our data indicated no sex bias in their probability of being captured at lights. Males provided 86% of trackings, and 87% of trackings of birds flying over the breeding area were males. Males landed 118 times; females 13 times. Only males were found on the ground, by night and day, apparently unassociated with burrows (three with and ten without transmitters), but subsequently digging burrows (n = 8). Of 19 birds banded as fledglings up to 2000, males were first recaptured nearing 4 years old (at lights and on the ground) and a female nearing 6 years old (in burrow). Among 37 fledglings, the sex ratio was even. Nine tracked males occupied burrows, as did two females, but the latter were older recaptures (10+ and 25+ years old). It appears that only males claimed existing, or dug new, burrows. They then attracted a mate to the burrow by means unknown, but from among females frequenting an inshore courtship area near the colony, or occasionally flying over the colony, at night. Females established in burrows, but then losing their mate, were able to re‐mate there, by calling from near the burrow or by attracting a mate in flight or from the postulated inshore courtship area. Both sexes sometimes took years to pair or re‐mate, possibly reflecting the dearth of available mates.