The peak of fall migration is approaching. Birds of all species are winging their way southward ahead of the months of cold and scarcity. September and October are months of flux and transition. Like a bear fattening for hibernation, I gorge on sightings of warblers, hummingbirds, tanagers and other favorites, knowing that I won’t be seeing many of these birds again until next spring. Their memories will sustain me, as will my feeders, which will still bring plenty of colorful and entertaining birds into my yard even in times of snow and ice.
Bird migration at any season is a spectacle. Many of the birds that nested in mountain hollows or vegetation-choked wetlands will winter in Central and South America, the Caribbean or other distant but warmer destinations. The following snapshots of fall’s bird migration capture the phenomenon’s drama.
The bobolink is a small bird in the family of blackbirds, which includes grackles, orioles and cowbirds. Nesting across North America during the summer, bobolinks retreat to South America for the winter. These small birds undertake amazing migrations, making a round-trip of about 12,400 miles to regions south of the equator in Bolivia, Paraguay and Argentina each fall. Come spring, they make the trip again, but in a northerly direction.
According to the website All About Birds, migrating bobolinks orient themselves with the earth’s magnetic field. These small birds are able to accomplish this feat due to iron oxide in bristles of its nasal cavity and in tissues around the olfactory bulb and nerve. Bobolinks also use the stars scattered across the night sky to guide their migratory flights. Capable of living as long as nine years, a long-lived bobolink will rack up some serious miles simply migrating to its nesting grounds and back to its wintering habitat each year.
Shorebirds, which in North America can consist of birds ranging from turnstones and sandpipers to willets and avocets, are champion migrants. For instance, the bar-tailed godwit makes an impressive non-stop migratory flight. This shorebird nests in the United States only in parts of remote Alaska, but this godwit also ranges into Scandinavia and northern Asia. Some of these godwits make a nine-day, non-stop migratory flight that takes them from New Zealand to the Yellow Sea of China and beyond, a distance of almost 6,000 miles each way.
Needless to say, since the godwits make no stops along the way, they must also go without food for the duration of their journey. The female godwit is larger than the male, but she still weighs only 12 ounces. The long-billed, long-legged bird is about 17 inches in length from the tip of the bill to its tail. That a creature so small can make such a distant, arduous trip and be the none the worse for wear is truly inspiring.
Many North American raptors migrate, but the broad-winged hawk dislikes the lonely aspects of solitary travel. Instead, these hawks form large flocks during migration, and in autumn the majority of these raptors travel past human-staffed hawk migration observation points, which are dubbed “hawk watches,” during a brief and concentrated period of only a few weeks. Observing the phenomenon locally is possible at the Mendota Fire Tower Hawk Watch site atop Clinch Mountain at an abandoned fire tower near Mendota, Virginia.
Broad-winged hawks are part of the family Accipitridae, which includes 224 species of hawks, eagles, vultures and other birds of prey. Broad-winged hawks are truly long-distance migrants. Many hawks passing over Mendota may end their migration as far south as Brazil. These hawks travel in flocks that can consist of hundreds or thousands of individuals. The birds conserve energy by soaring on thermals and mountain updrafts.
Most of the warblers that nest in North America retreat to Central and South America during the winter months. Few warblers, however, make as great a journey as the blackpoll warbler. Instead of migrating over land, this five-inch-long warbler undertakes a two-stage migration. The first half of the migration is a non-stop flight of about 1,500 miles. Every fall, these tiny birds fly over the ocean during this part of their migration, departing from Canada or the northern United States and not stopping until they reach various locations in the Caribbean. There they will spend some time recovering from the exhausting first half of their journey before they continue their way to such South American countries as Colombia and Venezuela. Once again, during the time they spend flying over open ocean, these tiny warblers do not feed.
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Wading birds topic for program
I’ll be presenting a program on herons, egrets and other wading birds at the September meeting of the Elizabethton Bird Club. The meeting will be held at 7 p.m. Tuesday, Sept. 6, at the Elizabethton campus of Northeast State Community College, 386 Highway 91. The meeting will be held on the second floor in Room 208. The free program is open to the public and will follow a brief business meeting.
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