LIHU‘E – December 17th 2013 – A new study by the Kaua‘i Endangered Seabird Recovery Project (KESRP) and US Geological Survey (USGS), has recently discovered that Hawaiian Petrels nesting on Kaua‘i travel thousands of kilometers to feed their chicks. Researchers found that breeding petrels on Kaua‘i undertake epic, multi-week journeys from their tropical montane nesting sites to a large area of ocean south of Alaska and the Aleutian Islands.
The KESRP is a project of the Department of Land and Natural Resources’ Division of Forestry and Wildlife and administered by the Pacific Co-operative Studies Unit of the University of Hawai‘i.
The Hawaiian Petrel (Pterodroma sandwichensis, known locally as the ‘Ua‘u) is endemic to Hawaii, meaning it is found nowhere else in the World. The species once nested on all the main Hawaiian islands but are now only thought to remain in much reduced numbers in isolated, remote regions on Kaua‘i, Lana‘i, Maui, and Hawai‘i. Because of this, the Hawaiian Petrel is now listed as an endangered species.
Researchers attached small solar-powered satellite tags to the backs of five Hawaiian Petrels nesting in Hono o Na Pali Natural Area Reserve System in the north-west of Kaua‘i. The satellite tags transmit signals used to calculate the birds’ locations every hour as they flew away from the island in search of food. The birds alternated between short and long trips, with the longer trips lasting as long as several weeks and involving journeys farther than 7,500km (4,600 miles).
“This kind of technology provides us with information on which areas of the ocean are important for petrels breeding on Kaua‘i, which is a critical piece of the puzzle for their conservation,” says Dr. André Raine, KESRP coordinator. “Their journeys to find food for their chicks are truly mind-boggling – one bird flew more than 53,000 km during a three month period as it traveled to and from its burrow in the mountains of Kaua‘i. That’s a distance far larger than the circumference of the Earth!”
The remaining number of Hawaiian Petrels is estimated at around 4,500 breeding pairs. On Kaua‘i, as with most of its range, the birds face a wide range of threats including being eaten by introduced predators (such as cats, rats and pigs), habitat change from invasive plants, collisions with power lines, and grounding by artificial lights. Additional threats at sea are less well known, making this satellite tracking study vital to the overall conservation of the species.
The work on Kaua‘i, which was partly funded by the Bureau of Ocean Energy Management, is one facet of a multi-species, multi-island study being undertaken by Dr. Josh Adams of the US Geological Survey’s Western Ecological Research Center along with a team of Hawaiian-based collaborators.
“This study tells us that petrels from Kaua‘i perform extreme, long-distance foraging trips to find food for their chicks,” said Dr. Adams, “Each petrel chick is therefore the result of an annual investment of 100s of thousands of kilometers of work at sea by its parents. To know that these birds utilize such an enormous area of the Pacific Ocean gives us context and perspective on the scales involved when we talk about marine resource planning, conservation and changes in our ocean ecosystem.”
HOW THE PUBLIC CAN HELP: The last Hawaiian Petrel chicks are now fledging from their montane colonies and heading out to sea for the first time. At this time of year, the general public is encouraged to look out for downed birds that have been attracted to artificial light sources and been grounded. Any downed seabirds should be passed over to the Save Our Shearwaters program (hotline 808-635-5117) for rehabilitation and release.