Control of invasive black rats Rattus rattus appears to lead to population recovery in a reintroduced population of New Zealand robins Petroica australis in a forest 'Mainland Island' on North Island, New Zealand
This study is summarised as evidence for the following.
Control predators not on islands for songbirdsAction Link
Control predators not on islands for songbirds
A before-and-after study in a forest remnant in the south of New Zealand’s North Island between September 1999 and September 2004 (Armstrong et al. 2006) found that the population of 40 New Zealand robins Petroica australis (refered to as North Island robins P. longipes) reintroduced to the study site in March 1999 declined to 18 individuals by September 1999 and then to 11 birds by September 2000. Following the control of introduced predators (black rat Rattus rattus and brush-tailed possum Trichosurus vulpecula) with brodifacoum baits between mid-2000 and March 2002, rat populations (measured with tracking tunnels) fell and the robin population increased to 19 birds. Poisoning was stopped in March 2002, the rat population increased and the robin population decreased to eight birds by September 2004.