Poster: Describing the moult of the South Island Fernbird: can birds be aged and sexed in the hand?

Paul R. Fisher¹ & David S. Melville²

¹27 Lud Valley Road, Hira, Nelson, 7071, New Zealand. wildlands.nelson@gmail.com

²1261 Dovedale Road, RD 2 Wakefield, Nelson 7096, New Zealand. david.melville@xtra.co.nz

The timing, extent and sequence of moult for juvenile and adult Fernbird (all five subspecies are Threatened – At Risk) has not been described – there is only very limited information from museum specimens. An understanding of plumage and moult is vital when determining the age and sex of birds while studying population structure, productivity, recruitment and survival for conservation management. Moult, being energetically expensive, is an important part of the annual cycle, which may be influenced by seasonal environmental (e.g. from extreme climatic events, food availability) and anthropogenic factors (e.g. seasonal changes in disturbance and predation), as well as long term effects of climate change on biogeographic populations. The morphology and moult of adult and juvenile Fernbird was described and photographed over the first year of a Nelson Birds NZ/Nelson City Council conservation study. Over forty Fernbirds were banded over the summer (2021/22) in the Nelson Haven saltmarsh – Wakapuaka Flats Esplanade Reserve and Significant Natural Area, to study the local distribution and abundance of birds prior to establishing a predator control programme. The key learnings from describing the moult are presented.