Boost for rare bird population
One of New Zealand’s rarest birds has surprised conservationists by breeding within months of their release on Mana Island, off Wellington’s west coast.
The shore plover or tuturuatu is one of the world's most threatened coastal birds. The small, stocky wader which is only found in New Zealand, does not usually breed until at least two years old, but this pair was less than a year old when they laid. Their two eggs were found in December 2007 in a depression in the ground under a log.
The breeding pair was among 41 captive-reared juvenile shore plover moved to Mana Island between March and May 2007. The small flock is monitored by members of the Ornithological Society and Friends of Mana Island.
During the breeding season from November to February, monogamous pairs will defend small territories containing their nest. Nests are well hidden amongst vegetation or between boulders, and both the male and female will take part in incubating the 2 - 3 eggs that are laid. Outside of the breeding season birds flock together but do not migrate.
Sue Caldwell, a Department of Conservation ranger on Mana Island noticed a pair of shore plover exhibiting territorial behaviour on the island in December. Ornithologists observed the birds’ behaviour, but failed to find the nest on a monitoring trip in wet and windy conditions. When Caldwell returned to the site three days later, she found the nest with two eggs being incubated.
"This early breeding is an exciting development, and is an encouraging sign that Mana Island provides suitable habitat for shore plover to establish and build a population," Caldwell says.
"We’re hoping that they’ll be able to thrive on the island. On the mainland the birds are vulnerable to human disturbance and predators."
Conservation projects
Shore plover are small, colourful shorebirds that were found throughout New Zealand until the mid 1800s. Introduced predators wiped them out on mainland New Zealand, and they were reduced to about 130 birds on Rangatira Island in the Chatham Islands. Currently ten pairs are held in captivity, mainly at the Pukaha Mount Bruce National Wildlife Centre in northern Wairarapa. Young birds produced by the captive flock are released on to predator-free islands as soon as they are old enough to fly.
One of these islands is Motuora in the Hauraki Gulf. In 1994, eight captive-bred shore plover were transferred there on a trial release. Since then more than 50 birds have been transferred to the island.
The Motuora programme is now at a challenging stage with released birds dispersing to neighbouring estuaries and beaches. To encourage the shore plover to remain on Motuora and establish a self sustaining population, a pair of birds is being held in an aviary on the island to act as a vocal attractant to the others. Further experimentation with the age class of released birds, release timing and the length of time they are held before release are continuing.
Shore plover are strong fliers, and colour-banded birds released on Mana Island have been seen on the adjacent mainland at Titahi Bay and Petone Beach. Some have wandered as far as Blenheim and the Manawatu Estuary, and one even flew back to its aviary at Pukaha Mount Bruce, a distance of more than 300 kilometres.
The world population, including birds held in captivity, is estimated at around 200.
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