Tuesday, August 5, 2008

Stealth Migrants

Years ago, as a fledgling birder, I assumed that May and September were just about the only times to see migrating birds. Sure, I vaguely knew about the migrant shorebirds in the summer, but I didn't fully appreciate that different birds are migrating year round. Even so, it is amazingly easy to miss the first few waves of migrants in the summer.

All birders (at least, I hope so) know that shorebirds migrate in the summer, when little else is happening in the birding world. Many birders do not realize precisely how early many of these shorebirds arrive; often, by June twentieth, the first fall migrants such as Long-billed Dowitchers, Greater Yellowlegs, and Least Sandpipers begin to arrive.

The migrants that really slip through unnoticed, however, are the early migrating passerines. Many of these are birds that also breed locally, such as Pacific-slope Flycatcher, Orange-crowned Warbler, Yellow Warbler, Black-headed Grosbeak, and Bullock's Oriole. In late July, I began noticing more Black-headed Grosbeaks around the neighborhood than usual. A pair or two probably bred somewhere in the immediate area, so I didn't think too much of it. Then, on July 26th, I found nearly half a dozen Black-headed Grosbeaks, an Ash-throated Flycatcher, two Orange-crowned Warblers, and a Bullock's Oriole on a short birding jaunt around the neighborhood. Hmm. Something fishy was going on! I flipped through San Diego County Bird Atlas...

And guess what? They were probably migrants! This really opened my eyes, and since then I've been hearing Black-headed Grosbeaks out the window and the flight calls of Yellow Warblers overhead. "So what," some birders would say. "You've been seeing those birds all spring and summer."

Well, now that I realize that they are migrants, I look at them with a new light. Soon, I should begin seeing migrants that do not breed locally such as Western Tanagers and Wilson's Warblers. In the meantime, I will enjoy watching migration unfold!

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