Ua U (Hawaiian Petrel) Videopodcast

‘Ua‘u (Hawaiian Petrel) Videopodcast

The ‘Ua‘u is the native Hawaiian seabird, it’s known as the Hawaiian Petrel or its Hawaiian name ‘Ua‘’u. It’s about 17” from head to tail and has a three-foot long wingspan, which is really large for petrels. A bird from Maui was tracked 6000 mile loop from its burrow at Haleakala all the way to the Aleutian Islands and back. So just image going to the grocery store, for a jog,and you had to go 6000 miles roundtrip to feed your children.

We know of three active colonies on the vast slopes of Mauna Loa with a few scattered nests elsewhere.

In the 15 years that I’ve worked with petrels one of our colonies had between 20-26 active burrows. Last year it went down to three active burrows.

These petrels are special, they nest only here and they come to land only to breed, so for about the first six years of their life, they’re at sea completely and then when they return to breed, they go to these very high elevations nest sites, above tree line, above 8,000 feet and they nest in these little holes in weathered lava flows. The colonies on Mauna Loa are where the adults breed, and the female lays one single, large egg in May, and then the parents take turns incubating the egg. During incubation, the birds go into a hibernation-like state: they don’t feed; they don’t eat, until after 54 to approximately 58 days, the egg hatches. The parents return to sea to feed and they come back up to the burrow to regurgitate squid and fish to feed the chick and that goes on for about four months. Just imagine how many grocery store trips that takes! Then in October-November, the chick comes out to stretch its wings to practice flapping and eventually the parents stop coming up to feed, and it forces the chick to fledge; go to sea for the first time to feed.

What we can’t see are the primary threats up there, which are feral cats and rats. Two predators; rats will take the eggs and probably small chicks and the cats will kill adults and chicks. From our monitoring we know that cats are the most serious threat up there and we’ve seen them trap-lining nests. We know that they go from nest to nest, checking out each one to see if there’s a bird out. We’ve seen on video that they (cats) will insert their body as far in as they can go in these small openings in the burrows, going as far in as they can. In other instances, we’ve seen them sitting outside the burrow just hoping that an adult or chick will emerge that they can grab, so those are the most serious threats, but there are some additional ones as well that are taking some toll. These include artificial lights: petrels come and go after dark and so they’re attracted to these lights and they will get disoriented, sometimes they will crash into buildings or other structures and then they’re just fair game for cars or dogs or cats. Also marine debris; we’re seen small bits of nylon that must come from some type of fishing gear that appears outside the nest, so the birds are ingesting this and then it’s being regurgitated at some point and that’s why we see it outside of the nest. In one carcass, we actually saw plastic in the digestive tract. One more threat I would characterize as important is maybe reduced food supplies: as the human population grows, and we take more and more from the ocean.

With assistance from Hawai‘i Natural History Association, the park is able to conduct monitoring up Mauna Loa about four times a year. And that’s the minimum we think we need to asses what’s happening with the nests up there. We’re also able to conduct live trapping up there for feral cats but this is very labor intensive and very expensive as we rarely catch cats in the colonies.

The endangered ‘Ua‘u is the most elusive bird species I’ve ever worked with. We rarely ever get to see the actual birds. With what interactions that I have had, you get so excited when you’re up at the colony, you go up to the burrows and there’s fresh poop, or there’s actual footprints. The neatest webbed feet, footprints of the bird going in the burrow, or down from the bird when it goes in and the down that gets stuck on the rocks and is blowing in the wind. You’re like “oh there’s a bird!” or even being in your tent at night at night, and the birds are coming in from the sea, and they come in so fast and you just hear the whoosh of the wind through their wings. It’s pretty amazing, and sometimes the calls at night of the birds; you can hear the calls throughout the colony. They have a really distinctive smell, so when you actually get your head down and smell its like “Ah! There’s a petrel!” In the 15 years that I’ve worked with them, I’ve only seen three live adults and one live chick, so there’s not too much interaction.