Study to show effect of pest-mammal control on nesting birds

31 August 2015

The nesting success of two of our favourite native bird species in Wellington City is under the microscope. Victoria University PhD student Nyree Fea is monitoring nesting tūī and fantails to find out how they respond to pest-mammal control.

A tui on a branch.

The nesting success of two of our favourite native bird species in Wellington City is under the microscope.

The main pest-mammal predators of native birds in our forests are rats, stoats, possums and cats. Rats are known to eat the nesting adults of fantails and other small birds. Control of these species is done in different ways, including bait stations, kill traps, and aerial pest control using mammalian toxins such as 1080.

To assess how introduced mammals affect native birds during the breeding season (typically September to February), Nyree will record the number of nests that fledge at least one chick.

She will focus her search in Council-managed public reserves in Wellington City. Her study sites include Zealandia, which has no pest-mammals, and reserves that currently receive no pest-mammal control.

Nyree chose to monitor nesting tūī and fantails to compare predation rates on different-sized birds. On average, adult female tūī weigh 90 grams while fantails average 8 grams. She hopes to discover what the success rates are for nests across a range of reserves with different levels of pest-mammals, to see how pest-mammal control affects medium-sized and small birds.

If you see a tūī or fantail nesting in a reserve, please call her mobile number (022 120 7237) or email nyree.fea@vuw.ac.nz. Watch for birds carrying nesting material, and keep your ears open – a noisy bird may mean you’re close to a nest. Nyree’s also interested in sightings of leg-banded tūī and fantails – if you see one, let her know the location of the bird and colour of the leg bands.

To see photographs of fantail and tūī nests, visit nzbirdsonline.org.nz