Nesting success of New Zealand pigeons (Hemiphaga novaeseelandiae) in response to a rat (Rattus rattus) poisoning programme at Wenderholm Regional Park

Anticoagulant poisons were laid within native forest at Wenderholm Regional Park (near Auckland) to reduce rat numbers during the summer months. Snap trapping indices and an artificial nest experiment confirmed the high potential for rat interference in unpoisoned forest patches outside Wenderholm, compared with the near-zero potential at Wenderholm. Over two breeding seasons, 70 New Zealand pigeon (Hemiphaga novaeseelandiae) nests were located and monitored. Nest predation was significantly lower at Wenderholm than in non- treatment areas, but hatching and fledging success were not significantly different, due to a high level of nest desertion at Wenderholm. Possums (Trichosurus vulpecula) were found to be nest predators, and their low numbers at Wenderholm confounded the results of the rat poisoning experiment.