Many tools used to stop predators of endangered birds

NA PALI — Noisemakers and motion sensors are just a few of the new tools scientists and conservationists are combining with traps to reduce predators in remote endangered seabird nesting areas.

On Kauai, most of those efforts center in the Hono O Na Pali Natural Area Reserve, a breeding and nesting area for Hawaiian petrels and Newell’s shearwaters.

“This reserve represents a key refuge for these imperiled birds, and predator control is one of the most important management tools we have in these remote colonies,” said Andre Raine, who heads the Kauai Endangered Seabird Recovery Project (KESRP). “Everything we do is geared towards improving the chances of both of these species and preventing their extinction.”

Raine and his fellows at KESRP recently completed an analysis of long-term radar studies on Kauai that revealed massive declines in populations of endangered seabirds on the island.

The study showed that between 1993 and 2013, populations of the Ao (Newell’s shearwater) declined by 94 percent and Uau (Hawaiian petrel) by 78 percent, according to a release from the state Department of Land and Natural Resources.

Scientists say Kauai’s endangered seabirds are also under threat from power-line collisions, light attraction and invasive plants.

And while efforts are ongoing to mitigate all threats to the endangered birds, trapping is a heavily used tool by management staff.

There are nearly 400 predator traps in the Hono O Na Pali Natural Area Reserve. Every week, predator control specialists helicopter into a remote field camp to check them.

Kyle Pias, of the DLNR Division of Forestry and Wildlife Natural Area Reserve program, said “We use a variety of them (traps) to eliminate the primary threats to the endangered seabirds. The rats and cats in this environment are truly feral, wild animals. The more tools we can have out on the ground removing them, the better.”

Traps used to catch cats are the same as may be purchased in most hardware stores.

Pias baits the trap with dry cat food soaked in shellfish oil, camouflages the interior with leaves, then sets the trigger. Trapping for the shy, savvy cats that inhabit wilderness areas requires great care and attention to detail, he said.

And the effort can become pricey, according to Basil Scott of the Kauai Community Cat Project, but said DLNR has “little choice.”

KESRP has begun experimenting with electronic noise-makers that emit a variety of loud noises, from the screech of a hawk to a blaring siren. The noise makers are motion triggered and aimed to scare predators away from areas that cannot otherwise be protected with traps.

Motion-triggered game cameras capture animals moving through an area and show when a rat or cat attacks a nesting bird, its eggs or chicks.


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