Acanthisitta chloris

Invertebrate food supply and reproductive success of two native forest passerines along an elevational gradient

Predation by mammals has been identified as the primary limiting factor of Aotearoa New Zealand native birds. Consequently, the ranges of many native forest bird species have contracted to cooler and higher elevation tracts of forest that support fewer introduced mammals. However, lower elevation forests are likely to be intrinsically more productive and able to sustain larger bird populations if control of mammalian pests removes predation as a primary limiting factor.

Recruitment, survival and breeding success in a declining rifleman population

We used detailed life-history data collected over a six-year period from a colour-banded population of riflemen (Acanthisitta chloris) at Kowhai Bush, Kaikōura, to estimate population vital rates and assess their likely contribution to a concurrent population decline. Both mean juvenile survival (18%) and mean adult survival (49%) were low in comparison with reports from other populations. In contrast, breeding success was high, with pairs producing c. 3 fledglings per season on average. High breeding success was likely associated with nestbox use.