Village turns off streetlights to save fledgling seabirds

In an attempt to help fledgling Westland Petrels, a New Zealand village is trialling an innovative strategy: it is switching off its streetlights to stop the youngsters becoming confused and crash-landing on to the road as they leave their nests.

The petrels – listed as Vulnerable – breed only along an 8-km stretch of coastal forest in the foothills near Punakaiki, a South Island village of fewer than 100 people. The 6,000 breeding pairs arrive from South America each March, an event celebrated by locals with a festival.

Westland Petrel breeds in an 8-km stretch of coastal forest on New Zealand's South Island (Richard Bonser).

The fledglings are born in burrows dug into the hillsides and emerge to feed in preparation for the long journey back to South America. But some, believed to be disoriented by lights, crash on to the road, where they are often struck by cars or eaten by predators.

Local birders believe the problem was worsened by the introduction of blue-white LED lights in the town last year. But in what is believed to be a first for New Zealand, the local transport authority has agreed to a localised blackout, with 15 streetlights turned off along a 3.4-km stretch of highway.

"It's been great," said Bruce Stuart-Menteath, who chairs the Westland Petrel Conservation Trust and has for many years helped relaunch disoriented birds and protect their habitat. "I’ve picked up only one this year. Typically a dozen would be the norm."

The Department of Conservation (DoC), the agency responsible for wildlife, reported that only 10 Westland Petrels had crash-landed in the town this year compared to the usual 15-25. Meanwhile, the fledgling seabirds have been crash-landing on roads in much greater numbers in Greymouth, the biggest town on the west coast, 44 km to the south.

"This year there were 22, compared to 10 being the highest number previously. And for the first time we are getting them in the CBD," said Darrell Haworth, the DoC's senior biodiversity ranger in Greymouth. 

Stuart-Menteath said the blue tinge of the LED lights could be confusing the birds as they feed on bioluminescent fish. "They fly over the sea and when they see a blue light they dive," he said.