Thursday, May 10, 2007

Spring Warbler Migration and International Migratory Bird Day

Spring Warbler Migration and International Migratory Bird Day

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Have you noticed friends or coworkers looking a little sleep-deprived lately? Perhaps these same people complain of a sore neck, and look past you into the trees while you’re talking. You may be encountering birders caught up in the excitement of spring migration.

Sure, a variety of birds have been migrating through central Illinois since February. During the late winter and early spring approximately 240 species of birds belonging to 39 families pass this way. But for most birders, the highlight of spring is songbird migration, and that becomes most intense in the next couple of weeks.

There are great numbers of birds and a great variety of species represented in this wave. According to Dave Enstrom of the Illinois Natural History Survey in Champaign, hundreds of thousands of individuals belonging to over 120 species move through or into central Illinois at this time.

Most exciting among these are members of a family of birds known as warblers. [The hooded warbler, right, was photographed at Busey Woods in Urbana by Greg Lambeth. Click here to see Greg's other bird photos.] These are strikingly beautiful little birds that average only about a third of an ounce in weight. Although they are small, warblers migrate long distances, from wintering ranges in Mexico, Central, and South America to breeding areas in the U.S. and Canada.

As they move north, warblers feed on insects, especially the caterpillars, bees and wasps that populate the crowns of trees as they flower and leaf out. (This habit of the birds accounts for “warbler neck” among birders who spend too much time looking up at them.)

Although 20 species of warblers breed in Illinois, only 7 species nest in Champaign County. Most individuals of the 37 warbler species that occur in Illinois are just passing through on their way further north.

Ironically, the highly fragmented nature of the central Illinois landscape makes for great warbler watching. Migrating birds that need trees to feed in when they stop are concentrated in urban areas and the isolated woodlands that remain here.

It seems almost foolish to try to describe in words the vivid beauty that prompts birders to get out before sunrise day after day. Some warblers are all about color. The blackburnian warbler’s throat and head, for instance, exhibit such a bright combination of orange and yellow that it looks to be on fire. [Click here to see photo and species account at the Cornell Lab of Ornithology's "All About Birds" website.] And the cerulean warbler—well, if you’ve only experienced “cerulean” as the color of a crayon, you’ve got to see this bird.

Other warblers are about patterns. The aptly named black and white warbler, for example, makes up for its lack of color in the same way a zebra does, by sporting stripes so bold they appear to be painted.

If you’re interested in catching up with spring migration, you might want to check out the observance of International Migratory Bird Day this Saturday, May 12, at the Anita Purves Nature Center in Urbana. Among the many activities scheduled, ornithologists from the Illinois Natural History Survey will be on hand to net and band birds in Busey Woods, allowing people to see how they work and providing very close up looks at some wild birds. [Further details available from the Urbana Park District at 384-4062.]

You can also enjoy spring migration with the Champaign County Audubon Society’s Sunday morning bird walks at Busey Woods, which run from 7:30 until about 9:00 a.m., and continue through the end of May.