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Checklist 2022

Checklist of the birds of New Zealand. Fifth Edition. 2022, Occasional Publication (No. 1), 332 pp

OSNZ Checklist Committee (2022)

Article Type: Occasional Publication

Sexing of the endangered Floreana mockingbird (Mimus trifasciatus) using morphometric measurements

Notornis, 69 (4), 256-263

E.M.R. Reyes; A.N.H. Smith; D. Rueda; C. Sevilla; D.H. Brunton; L. Ortiz-Catedral (2022)

Article Type: Paper

Abstract: Male and female adult Floreana mockingbird (Mimus trifasciatus) have monomorphic plumage features that make them impossible to sex in the field. In this study, we use discriminant function analysis (DFA), a widely used technique, to assess the best measures to determine sex. We measured six morphological characteristics (mass, beak depth, beak width, tarsus length, wing length, and head-beak length) for birds of known sex (determined by molecular techniques) from the two extant populations of M. trifasciatus on Champion and Gardner islets, within the Galápagos archipelago. Using a coefficient of sexual dimorphism, we found that males are significantly larger than females in three of the variables. Discriminant functions using wing length and a combination of wing length + mass, and wing length + tarsus length could classify birds with a 98% level of accuracy. Furthermore, we were able to estimate a robust cut-off point to determine the sex of individuals in the field through a decision tree, using only wing length as morphological variable. Fast and accurate sexing of the bird based on one variable will reduce handling times and minimise stress for captured birds.

Post-translocation movements and ranging behaviour of roroa (great spotted kiwi, Apteryx maxima)

Notornis, 69 (3), 135-146

P. Jahn; J.G. Ross; V. Mander; L.E. Molles (2022)

Article Type: Paper

Translocations are increasingly used in kiwi (Apteryx spp.) conservation management, and their outcome is largely influenced by post-release dispersal and survival. A translocation of roroa (great spotted kiwi, A. maxima) to the Nina Valley, near Lake Summer Forest Park, is the first reintroduction of the Arthur’s Pass roroa population. In 2015, eight wild-caught adults were translocated from Arthur’s Pass National Park, following the release of ten captive-hatched subadults during 2011–13. We monitored the translocated kiwi by radio telemetry during 2015–17. Dispersal was highly variable among the released wild birds. The straight-line distance from the release site to the last recorded location ranged 0.5–10.3 km. Seven of the wild birds remained in the Nina Valley and covered an area up to 1,700 ha (95% utilisation distribution). Releasing the wild birds had no measurable impact on the ranging behaviour of previously released subadults. The current population founder group comprises a maximum of 13 unrelated individuals, and therefore further releases are necessary for a genetically viable population. Additionally, expansion of the pest-controlled area is crucial for the long-term persistence of the reintroduced population in the Nina Valley.
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