Monday, September 7, 2009

An Improbability of Shearwaters

After a few days of very high winds, I was thankful (after experiencing my first 8-10' seas yesterday) to see calmer seas prevail this morning when we went out on the Western Explorer. On our way out to where the whales had been spotted, I saw a few small groups of sooty shearwaters - a bird I have never seen near the San Juan Islands. Shearwaters are outer coast birds, mostly pelagic and not coastal, so its crazy to see them so far inland! They are smaller than most of our local gulls but their thin, lance-shaped wings reminded me of the black-footed albatrosses I saw off the California coast last spring. I was super excited about this, but had no idea that the true bird-watching treat was yet to come.

We met up with the whales about four miles south of Cattle Pass and as we followed them back towards San Juan Island, we had to take a diversion to check out what was easily the largest bait ball congregation of birds I've ever seen in the San Juans. Literally thousands of sea birds - I counted at least nine different species - were either hanging on the surface or actively taking part in the giant feeding frenzy:


Among the bait ball were hundreds more sooty shearwaters. I have a feeling these guys probably won't be hanging out for too long, as they are on an amazing migratory journey - actually the longest documented animal migration. They breed off the coast of New Zealand and basically travel make a figure 8 across the entire Pacific Basin, going east towards South America, then north towards Russia or Alaska and then looping east again and down the entire coast of North America before heading back to New Zealand, for a total of about 40,000 miles a year. The only animal that can rival those distances is the Arctic tern, which flies from the Arctic to Antarctica and back every year.

What amazed me when observing the shearwaters today is that they dive underwater, which I didn't know. It's very weird to see a gull-like bird dive like an auklet while sitting on the surface. I guess they can dive down well over a hundred feet underwater! I was reading about them later in the day and learned that a group of shearwaters is called an improbability, which seemed like a very appropriate name given the improbability of our sighting today. The shearwaters were easy to pick out from the similarly dark Heermann's gulls because they were sitting at the surface with their wings bent and held up in the air, as shown in the photo below.


Behind the sooty shearwater in the above photo is actually another shearwater species, perhaps a pink-footed? (EDIT: Confirmed pink-footed shearwater by a fellow birder! How cool!!) I didn't even notice it in the field because there was so much to look at in this bait ball. We slowly drifted towards the center of the action, and we could actually see the bait fish bubbling up above the surface. They were in such a tight school that some of them were being pushed up above the water! You can see all the silver fish in the center of the photo below (note the shearwaters in the background with the raised wings):


The feeding was very good for these birds! Check out the gull with a fish in this shot:


Several more birds have fish in this photo, with a few more gulls coming in to join the fray:


As excited as I was about the shearwaters, I did take a moment to notice this lovely common murre in winter plumage:


After a while we made our way back over to the whales. Just like they've been doing all week, the whales have been confusing us by showing up in weird places doing weird things, leading to a lot of mistaken identities. As I was talking about with my friend Jeanne (who has also been blogging about the ID confusion), we are all back to Whale ID 101 after this week! The group of whales originally identified this morning as J-Pod turned out to be K-Pod with part of L-Pod! Despite what we think we see on the water, looking at photos once we're home always helps to confirm who we did or didn't see. Here is L82 Kasatka surfacing off of South Beach this afternoon:


I always associate the first week of September with the arrival of the Steller sea lions in the San Juan Islands. They've left their breeding rookeries up in BC and we get some of the males down here to forage from now until next May. I saw my first Steller in Cattle Pass on August 30th, and as of today there were twenty or more of them hanging out near Whale Rocks. Here are a few of them, both hauled out on the rocks and in the water, with the Cattle Point lighthouse in the background:


On the way back to Friday Harbor we even saw a Dall's porpoise in San Juan Channel. It was an awesome whale and wildlife day today!!

3 comments:

  1. Hi Monica,

    Wonderful story and photo's with great research on your part, I did not know about the improbability of shearwaters.

    Thanks, wish I was there.

    Kathy
    Andrich

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  2. Monika:

    Saw your Tweeters post. Definitely a Pink-footed Shearwater there behind the Sooty--a new San Juan Co record! I've never heard of one so far into Puget Sound.

    Sooties are another matter. Don't know if you've ever seen Lewis and Sharpe's Birding in the San Juans, but there have been flocks in that area in the past (rarely), but if memory serves Mark had a large early Sept flock long ago also.

    Best

    Scott Atkinson (Wild Plants of the San Juan Islands)

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  3. Cool pictures of the feeding frenzy. Glad you got confirmation on the second shearwater species. There've been thousands reported in the Cove at Seaside, but the were only there a day. Curious to see if you spot more.

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