Wednesday, April 18, 2012

San Juan Channel: Bird Survey and Branded Sea Lion

Yesterday afternoon we participated in a marine bird survey transect down San Juan Channel. In the fall, a class at the University of Washington Friday Harbor Labs has been conducting surveys down this transect for birds and marine mammals over the last several years, and my friend Phil is interested in establishing a year-round data set following the same transect. Seven volunteers gathered to do the first one yesterday on a drizzly but calm afternoon.

While on the water I saw 13 bird species, the vast majority of them rhinoceros auklets. We did one survey going north to south, and one going south to north, and both times the other side of the boat saw WAY more birds than my side in terms of numbers. Still, we counted several hundred rhino auklets in each direction. Some other highlights included almost a hundred common murres, about 20 red-breasted mergansers, and a single long-tailed duck, the latest in the season I've seen one.

In terms of marine mammals, we had only one harbor porpoise and one harbor seal within our survey zone, but there were other marine mammals out there. Lots of Steller sea lions were hauled out on Whale Rocks, and this California sea lion was hauled out on the Reid Rock buoy just outside of Friday Harbor:


You can't tell in the above photo, but this sea lion is branded with the number 670, and this is the fourth spring in a row he's been hauling out on this same buoy! He was branded in Puget Sound in 2000 as a two or three year old, weighing 235 pounds. He has been seen multiple times on San Miguel Island, California (where he was a territorial male in 2008), as well as at Cascade Head, Oregon, and in the Strait of Georgia, British Columbia. That's a known range of over 1200 miles! Pretty amazing. As a 15 year old (or so) now, he probably weighs 800+ pounds. According to Wikipedia, the average lifespan is about 17 years in the wild. It will be interesting to see how many more years he keeps returning!

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