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Spring has sprung here in the northeastern U.S.! Birds are chirping and swooping, flowers are pushing up through the mulch, and the first few pesky insects are out and about. As I sat in the yard planting some seeds for later transplanting, I wondered which birds show up first. Which voices was I hearing on that first 70-degree day of spring?
Migration Map
According to eNature.com, 10 species of birds arrive in the northeastern U.S. before April 15. These include the purple martin, ruby-throated hummingbird, barn swallow, and black-and-white warbler. I have also heard the red-winged blackbirds!
The ruby-throated hummingbird winters in Central America. In March, they begin a flight across the Gulf of Mexico and continue northward across the U.S. By April they reach the middle of the country; by May they reach the northern U.S. and southern Canada. As with other species, the timing of the move depends on the weather and availability of food sources.
Why Do Birds Migrate?
Did you ever wonder what makes some species fly south while other stay for the winter? Why do the chickadees hang around to visit your feeders when the barn swallows flee?
Food scarcity seems to play a big role, but just because you feed the birds doesn't mean they'll stick around. Birds need to have a reliable day-to-day food source. This ties in with the theory that birds that eat insects, fruit, and nectar will leave places where these foods become scarce during the winter or other seasons -- hence birds that fly south for the winter and north in the summer.
Frequent Fliers
Birds also return north in the summer for breeding. Many species prefer to return to a familiar nesting spot – often the same exact place, year after year.
Some facts about flights:
- Arctic terns migrate from Antarctica to Massachusetts. They travel 1,000 miles per week for a total trip of up to 22,000 miles!
- Hawks that travel from Central America often travel in groups of as many as 100,000.
- Most songbirds fly at speeds of about 20-30 mph; waterfowl fly at 30-50 mph.
- The average altitude for migrating birds is less than 2,000 feet, although some will fly as high as 6,500 feet.
More about birds on CR4:
How the Bird Gets the Worm (Robins)
Smack! Why Do Birds Fly Into Glass?
Think it's a Bat? It Might be a Bird! (Swallows)
The Cackling Grackle Migration
Resources:
http://www.enature.com/birding/migration_home.asp
http://www.sciencedaily.com/releases/2007/03/070302082310.htm
http://wild-birds.suite101.com/article.cfm/why_do_birds_migrate
http://www.coolquiz.com/trivia/explain/docs/birds.asp
http://www.zoosociety.org/Conservation/BWB-ASF/Library/BirdMigrationFacts.php
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Re: Spring Bird Migration
