Sound lures bird to nest
A rowdy "boom box" for birds on Tawharanui Open Sanctuary cliff tops is being hailed a success as an island-nesting diving petrel seabird is discovered for the first time breeding on the mainland.
A nocturnal exercise showing the nuts and bolts of the seabird sound system saw a group of volunteers make a surprising discovery on November 5.
Out for a session of bird banding, the group was being shown how the "boom box" for birds works in broadcasting the sounds of an active seabird colony out over the sea at night.
The theory is the rowdy goings on will make the birds think there is a breeding colony already established and help them set up house there.
So when the solar powered sound system was turned off to hear what the area sounds like naturally, Conservation Department seabird specialist Graeme Taylor heard some unexpected noises in the darkness.
A quick clamber down a steep slope saw a disgruntled petrel chick pulled from a burrow under flax.
Grey-faced petrels re-established naturally in the pest-free mainland sanctuary three years ago. But the realisation this was a diving petrel chick caused a flurry of excitment, Leigh-based Hauraki Gulf seabird specialist Chris Gaskin says.
Up until now the birds have only been known to breed on islands, as they are very susceptible to predation and usually stay close to established breeding areas.
"We're a bit ahead of ourselves," he says. "The sound system only went up last year. We were keen to see what birds we could attract but getting a species to breed in response to this system in such a short time is amazing."
While coastal visitors may not fancy being pooped on by seabirds, getting them re-established on the mainland coast is an important part of restoring ecosystems, Auckland Council Northern Parks Open Sanctuary co-ordinator Matt Maitland says.
"Seabirds play a major role in the ecological restoration of sites such as Tawharanui Open Sanctuary by importing marine nutrient to the land where it is deposited as guano. This improves soil fertility, providing the growing conditions for plants and associated land-based animals," he says.
The sound system's relatively low cost at several thousand dollars is also a bonus. Diving petrels have already been artificially established on Motuora Island but this saw intensive handfeeding in artificial burrows to get the birds to accept the island as their home, which takes a sizeable volunteer team, Mr Gaskin says.