Audublog

In search of the elusive Ashy Storm-petrel

June 14th, 2013 · by Garrison Frost

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From Anna Weinstein, Seabird Program Manager:

You know you’re on the cutting edge of seabird conservation when you’re clambering up the side of a rocky outcropping, sticking your face into holes searching for a certain musky smell. That’s what I was doing about eight months ago when I spent two days and night surveying for the rare and elusive Ashy Storm-petrel on the aptly-named Bird Rock off Pt. Reyes, just north of San Francisco Bay. (photo above by USFWS)

I was privileged to be in the company of one of the world’s leading experts on storm-petrels, Harry Carter. Carter, who possesses a dry wit that kept the expedition loose throughout our trip, is with the California Institute of Environmental Studies. To call him the leading authority on storm-petrels might be an understatement. As far as Ashy Storm-petrels go, he’s the guy.

And thank goodness for the bird that there are people like Carter. The Ashy Storm-petrel, a smoky gray seabird that spends most of its life out over the ocean, is struggling for its very existence. Audubon put the bird on its Watchlist because of severe population declines as well as numerous threats to breeding and foraging habitat.

A few years ago, Audubon California and other conservation groups unsuccessfully fought to place the Ashy Storm-petrel on the Endangered Species List. We felt then, as we do now, that the bird’s rapidly declining population and small geographic distribution merited this protection. More recently, we have been working with state officials to protect important breeding areas for this bird. At the same time, we have been advocating for fishing policies that leave enough food in the water for the birds.

The Ashy Storm-petrel lives and breeds almost entirely off the coast of California (its population does spread southward into Mexico), and because of this we feel a certain obligation to protect it. It’s one of our California birds, and an important part of that natural legacy in which we Californians take so much pride.

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The goal of this trip was to understand the status of this swallow-sized seabird at one of its most accessible breeding sites, which had not been assessed in twelve years. Bird Rock is less than a mile from the Pt. Reyes mainland, but is free from introduced predators such as rats and mice, which can devastate seabird colonies. Carter thinks up to 30 percent of the roughly 6,500 Ashies (bird scientist lingo) live on these smaller colonies, away from the larger population centers at the Farallon Islands and Channel Islands. These smaller colonies can be a critical piece of the conservation future of a species, as they can help buffer a species from catastrophic events that may take place at larger colonies.

Just a few weeks before our trip to Bird Rock, Carter had led a team to explore other rocky islands much further north off Mendocino County coast within the California Coastal National Monument. During that trip, his team made the remarkable discovery of several breeding sites for the Ashy Storm-Petrel. It was the first time that anyone had found the bird nesting this far north since 1926. This was an incredibly positive development for this species – and another reminder that it’s not too late to turn things around for this bird.

Back to our trip to Bird Rock: Carter carefully selected the days to coincide with the breeding season for Ashies, which follows the breeding season for the island’s Western Gulls and Brandt’s Cormorants. It is also the time when the seas are the calmest. Rough seas, even so close to shore, can scuttle a landing and cause a field survey to be canceled.

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A tent on the rocks (photo by Colin Grant)

We left shore in an inflatable zodiac with what seemed like an insane amount of gear for the time we were on the island: mist nets, flashlights, bags, measuring devices, food, camping gear, you name it. We landed successfully and quickly were besieged by clouds of kelp flies which plagued us throughout the trip. You cannot imagine how many flies were in the air – and this was the light season for flies?

Bird Rock is not exactly the Holiday Inn. As a human, I found the accommodations lacking, but birds simply love the place. It is an important roosting spot for Marbled Godwits and other shorebirds. Turnstones were roosted on the inner part of the small cliffs over the water. A flock of Phalaropes played in the waves for hours – a beautiful sight. Six Black Oystercatchers called and flew back and forth, in their territorial way. All in all, a tiny little speck of rock and dirt with huge benefits for seabirds and shorebirds taking advantage of the rich food resources off of Pt. Reyes.

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This is a photo of me, Anna Weinstein, looking into a hole for Ashy Storm-petrels. (photo by Harry Carter)

Once on the ground, we systematically surveyed the accessible parts of the island, starting with the terraced area known to have harbored nests during a survey in 2000. Ashies nest in deep crevices, sometimes several feet deep. We shone powerful flashlights into the crevices and put our noses to the mouths of the crevices seeking the distinctive musky smell of Ashies.

 

Aha! A fat, fluffy grey chick! Completely still and silent, waiting and waiting for its sleek grey parent to show up under cover of night with a beak full of larval fish or krill. A precious sign of hope for the future of Ashies.

 

We ended up finding five chicks and 38 potential nest sites, for a conservatively estimated population size of 12-28 pairs. This number is consistent with the only other two surveys that had taken place there in the last 40 years. At night, we set up the mist net. I ended up falling asleep and was jostled awake when we caught our first adult returning to its burrow to feed its chick. We ended up capturing and releasing six adults, less than in the 2000 survey.

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Mist netting on the island (photo by Colin Grant)

The following morning, we looked around a little more and then got back in the zodiac for our return to the mainland. I already knew about the lonely, hard life of the Ashy Storm-petrel, but I would say that a night on Bird Rock offers even more perspective. The funny thing is of all the obstacles to bringing back this terrific California bird, the terrain is probably the least intimidating. This is a battle fought not just on these rocky outcroppings, but in Sacramento and Washington, as well.

Categories: Audubon California · Bird conservation · Bird Habitat · seabirds

2 Comments so far ↓

  • Garry George

    Great report from someone who obviously loves Storm-petrels, although I am not sure why! We need to do whatever we can for this bird.

  • Betty Turtledove

    Aren’t they the ones who defensively puke vile-smelling vomitus on the heads of those perceived as a threat?