The awesome phenomenon of bird migrations

Our long summer days are numbered, and fall, followed closely by winter, will be here before we know! Each year in September, there are one or two days when the nighttime temperatures drop below 40 degrees. The cooler temperatures and shortening daylight hours send a signal to all of us that winter is on its way.

Neotropical birds are preparing to migrate and by September many are either gone or are flocking together to prepare for the big trip. For several years, flocks of Tree Swallows and Violet- green Swallows have visited us in mid-September. One afternoon, nearly 500 birds visited our property. We do not KNOW, but we think that the swallows who used our nest boxes came back to re-orient to our property before heading south, and they brought the entire migrating flock with them! We have had other swallow flocks visit in September with 100 to 200 birds. It gives us hope that some of the birds will navigate back to our property when they return next spring.

Most birds migrate in flocks to provide guidance from the elders, and they either travel in close groups or keep in vocal contact, as with the night-migrating thrushes and sparrows. They can be heard throughout the night giving single calls overhead as they make their way south using stars and magnetic signals to guide them.

The juvenile Rufous Hummingbirds hatched at our property are showing a definite bulge around their abdomen as they "tank up" for their first migration. It is amazing that they will instinctively orient themselves and fly south to a place they have never seen for the winter sojourn. I have read that they migrate singly, so they do not benefit from other individuals guiding the way. They simply depend on their hard-wired instincts to take them 2000 miles south.

Such bird wisdom is a mystery we are now beginning to understand. New studies are showing the complex systems of genetics, hormones, learning, and adaptive behaviors required for a small bird to accomplish such a feat. Obviously, the birds have successfully found ways to make the hazardous journeys and their genetic guidance systems give them tools for the job. I find it a wonderful phenomenon for reflection as I watch the flocks of small birds about to embark on such a major journey. Farewell, may the wind be always at your back.