Thursday, July 4, 2019

Scripps's Murrelets off San Diego

Birds on the water!

Two dark dots, sitting on the water ahead: murrelets!

Murrelets are "always" in pairs. They swim together, dive together, fly together. A singleton is rare. Three together is also quite unusual.

Now will they stay there long enough for the boat to approach more closely? If not, then they may get away unidentified further.

We are 15 miles offshore from San Diego, following the Mexican border westward. The water has been getting gradually deeper as we progress, but then became quite shallow again as we crossed over the south end of the Nine Mile Bank. Birds increased as the underwater hill forced bottom currents to the surface, carrying nutrients toward the surface that fish feed upon. Birds followed.



Okay, there they are. No white scapular patches, so not Marbled Murrelets. Besides, Marbleds don't regularly get this far south and are found only with 2 miles of the beach, or in the bay. And that would be in winter, not early June.

Being spring, we expect Scripps's Murrelets. They nest on nearby islands. Otherwise they generally are found farther offshore--60 miles or more, as they follow the sumer warm water currents northward as far as Washington State in late summer and fall. At any time Craveri's Murrelets should arrive from their Mexican breeding grounds and be the expected murrelet for the rest of summer and early fall. And in later fall there is a chance for Guadalupe Murrelet, too, also up from Mexican waters. Though that is a much rarer species.

These seem a little paler gray than blackish. Though it's a bit hard to tell in the harsh overcast gray marine layer typical in the summer mornings. It will clear soon and we'll have blue skies and sun. Their tails aren't sticking up in the air like a Ruddy Duck, exposing long white undertail coverts. So they probably aren't Craveri's Murrelets. They are very similar, though, so when they fly we'll try to confirm. Craveri's have dark underwing linings. We'll see the wing linings unless they fly directly away, as they often do.

One more thing to check. Similar to the head pattern difference between Western and Clark's Grebes, Scripps's Murrelets have the eye surrounded by the dark crown, Guadalupe Murrelet has the white cheek arching up over the eye.

Nope. Eye is "in the black." Scripps's Murrelets!

Scripps's Murrelet
Scripps's Murrelet
Scripps's Murrelet
Scripps's Murrelets. Off San Diego, California. June 9, 2019.
Scripps's Murrelet

3 comments:

  1. I really love this format of walking through your thought process of a bird ID! It's fun to follow along and learn in this fashion. Also enjoyed the bit about why bird action is expected to increase when nearing an underwater hill. Great stuff, as usual!

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    1. Thanks Miles! This is really great feedback to give a blogger. Not just saying that you liked the content, but exactly why. Now I can post similar articles in the future, knowing what my readers like.

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  2. You're very welcome. I'm looking forward to it! Walking us readers through tricky (shoot, or even relatively simple) identifications like we are w/ you, working it out together, would be a great series...

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