The balancing act of nest survival: survival of a small endemic bird in the face of ship rat predation and other risk factors

What is it about?

Predation of indigenous birds by ship rats has been implicated in the decline of many endemic species. We investigated the prevalence of rat predation on nesting New Zealand Fantails (Rhipidura fuliginosa placabilis, [Rhipiduridae]), and its importance relative to other factors related to the nest microsite. 106 nests were surveyed across forested reserves in Wellington City, New Zealand. RESULTS: Approximately 45% of 81 nesting attempts that were monitored in urban Wellington successfully fledged chicks: one in four nests being abandoned or deserted and just over one in four suffering predation. Nests built on thin branches were more likely to escape predation from ship rats than those built on thick branches. Our research suggests that nesting strategies of Fantails involve trade-offs and strategies that might protect them against one threat (arboreal predators such as rats), might expose them to others (e.g. spillage of nests by wind).

Featured Image

Photo by Karl Anderson on Unsplash

Photo by Karl Anderson on Unsplash

Why is it important?

Fantails are a common endemic species able to cope with moderate levels of nest predation, however conservation of small endemic birds with less resilient breeding strategies is likely to require management of ship rat populations to low levels.