<ir="ltr" id="docs-internal-guid-4f11cc2f-cf1a-6aa7-146f-7ccd7dd6ac09">This past Saturday we conducted the annual Arb bird count. Since 2000, this survey has helped the Carleton community track changing bird populations. Of particular interest in the bird count is a group of small, difficult to identify birds—the warblers—that, as we speak, are in the midst of their spring migration. This year we identified eight different warbler species, the Blue-winged warbler, Tennessee warbler, Nashville warbler, Yellow warbler, Blackburnian warbler, American Redstart, Ovenbird, and Common yellowthroat. The number of warbler species we see each year depends on whether or not the bird count occurs during peak migration. Other species that have been identified in past years migrating over the Arb include the Golden-winged warbler, Orange-crowned warbler, Northern parula, Chestnut-sided warbler, Magnolia warbler, Cap May warbler, Yellow-rumped warbler, Black-throated green warbler, Palm warbler, Bay-breasted warbler, and the Blackpoll warbler (to name a few).
The onslaught of warblers comes to Minnesota mid-April but does not reach its peak until the warmer month of May. The exact date varies; warblers are insectivorous and move north as their food source comes available. Because warblers are flapping away to their breeding grounds, the spring migrations are highly concentrated. In contrast, the fall migration to the south is a more spread out affair. When looking for warblers it is best to look in the forest. In particular, smaller wooded areas surrounded by fields or prairie will concentrate the warblers, making it all the easier to view them.
Migration is an impressive feat, and the spring warbler migration is no exception. The Blackburnian warbler is on its way to Canada and the northernmost reaches of the United States to breed. The warbler mainly spends its winters in the Andes and then flies up through Central America, across the Gulf of Mexico, to be seen in the Carleton arb just in time for the count. When it comes to impressive migrations, however, the Blackpoll warbler takes the cake; it is thought to migrate the farthest of all the warblers. This bird winters in Northern South America, and breeds in boreal forests of North America. Its migration can be anywhere from around 2,000 to nearly 5,000 miles long. It takes days traversing the Atlantic ocean before either stopping along the east coast or continuing on to Canada and Alaska. Not too shabby for a ~12 gram bird.