Eradication of rats from atoll helps storm-petrels prosper

Tristram’s storm-petrels are making a comeback on Midway Atoll National Wildlife Refuge.

Federal wildlife officials said for the first time they’ve observed Tristram’s storm-petrels rearing their chicks there.

The restoration of nesting areas for the petrels comes after rats were eliminated from the atoll and the planting of native bunch grass known in Hawaiian as kawelu.

“Now that Midway Atoll Refuge is completely rat free, these chicks are safe from the threat of rats preying on their eggs or new hatched chicks,” refuge manager Robert Peyton said in a release. “To be able to know that work paid off to help this vulnerable species survive is very encouraging.”

Adult birds were heard calling in flight in February.

Wildlife researchers identified six burrows with potential breeding activity and used a wireless infrared camera in their observation to detect three healthy chicks on March 22. The chick count increased to four after a nest was discovered on Midway’s Eastern Island on April 24.

Tristram’s storm-petrels, or Oceanodroma tristrami, weigh about 2.5 ounces and are covered with black feathers.

They breed in the Northwestern Hawaiian Islands and islands of the Japanese archipelago at similar latitudes.

Midway Atoll falls under the authority of the Papahanaumokuakea Marine National Monument and the research of the U.S. Fish and Wildlife Service.

Researchers said they’ve had difficulty estimating populations of the Tristram’s storm-petrels, because their nests are difficult to detect and their activity has been rarely observed.

The International Union for Conservation of Nature has listed them as near threatened because of their limited breeding range, according to the Papahanau­mokuakea Marine National Monument.