Monday, October 12, 2015

From islands off Baja


This is one of those times when I don't have great pictures, but I'm going to show a few images because they represent an important record.

At the end of the day today there were thousands of Black-vented Shearwaters (Puffinus opisthomelas) flying north past Bodega Head.

These are small shearwaters, and they were about 1/4 mile offshore, but you can still see their distinctive profiles with stiff wings.  And in these images, on some individuals, you can just make out the coloration dark upperparts and light underparts.




At ~5 p.m., through a spotting scope, I counted ~135 Black-vented Shearwaters/minute (on average).
 

Black-vented Shearwaters are generally a southern species breeding on islands off the west coast of Baja California, and dispersing north to Point Conception.  In some years, they make it to Monterey Bay.  When the water is warm, they make it to Sonoma County.  (Rarely they make it as far north as British Columbia.)  Their abundance off Bodega Head in 2015 is probably related to El NiƱo and warmer water conditions.  Water temperatures reached over 16°C (61°F) today (about 3°C above average for this time of year).

Because they're rare off Bodega Head, I don't have great pictures of this species, but here's a photograph from Monterey Bay on 22 August 2014 (with a couple of cormorants and a larger and darker Sooty Shearwater for comparison):


Black-vented Shearwaters can be seen close to shore, so watch for them if you're at the coast this fall.

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