The spring migration is now underway! Vireos, orioles, warblers, tanagers, swallows, hummingbirds, flycatchers, thrushes, and more have begun pouring into the Carolinas, exhausted from a journey thousands of miles long from their winter abodes in the Caribbean, Central America, and South America. The ruby-throated hummingbird, for example, weighing the same as 5 paperclips or less, undertakes a 500 mile, 20 hour non-stop flight across the Gulf of Mexico from the Yucatan Peninsula to the Gulf Coast of the United States. Many will perish during the migration, and those who make it to the north shore of the Gulf must still run a suburban gauntlet of cats, windows, and disorienting nighttime lights (many songbirds are nocturnal migrants). "So why migrate?", you may ask. Birds that we call neotropical migrants, ones that make long-distance migrations between the Americas, have evolved over millions of years to capture and consume insects with maximum efficiency. Insects make up a diet higher in protein and nutrients than seeds and other vegetative matter. During the last Ice Age, these "neotropical migrants" were still tropical species, trapped in an equatorial environment that was warm enough to support insects year-round. At this time, glaciers and ice caps spread as far south as Pennsylvania and Ohio, and the Carolinas were dominated by boreal forest. Eventually, as the climate warmed, insects could thrive during summer far into Canada and Alaska. Neotropical migrants took an ecological risk: by engaging in long and dangerous migrations twice a year, they could experience the "best of both worlds": plenty of insect food to feed their young in less competitive northern breeding grounds, and ample insect food in the tropics during winter, when insects in the US and Canada are dead or inactive.
Take time this spring to find some of these colorful and fascinating wonders of the avian world!
Join the Carolina Young Birders Club on our Warbler Walk at Latta Park in Charlotte on April 26th. More details on the "Events & Field Trips" Page. Hope to see you there!