Notornis, 50 (4), 191-201
Article Type: paper
This study provides a first description of breeding biology of the South Island saddlebacks (Philesturnus carunculatus carunculatus) and the first comparisons with North Island saddlebacks (P.c. rufusater), using data collected from Ulva (Stewart Island), Breaksea (Fiordland) and Motuara (Marlborough Sounds) Islands, New Zealand. We found courtship and copulation behaviour to be similar to that of North Island saddlebacks. So too were nest locations, heights and materials, with nest materials determined by their proximity to the nest site. On Motuara and Ulva Islands, most nests were located in natural cavities (54% and 80%, respectively), while on Breaksea Island, 67% of nests were in flax (Phormium cookianum). In the recently established Ulva Island population, saddlebacks had a median and maximum clutch size of two and laid a maximum of two clutches. This contrasts with translocated island populations of North Island saddlebacks where up to four-egg clutches and four clutches per season have been recorded for pairs breeding in the first few seasons post-release. Incubation and brooding behaviour was like that described for North Island saddleback. A small number of yearlings bred successfully on Ulva Island (0.18 birds/ha), but no yearlings bred on Motuara (0.42 birds/ha) and Breaksea (0.42 birds/ha) islands.