Summer is slowly slipping away as we approach the end of August. There are many signs of the season's end: Labor Day, Back-to-School sales, mums for sale/on display all over town, etc. One of the surest signs of summer's end for me is bird migration.
Many folks are aware of bird migration in the spring. Robins and bluebirds and others return from their wintering grounds and fill the air with song. Just as dramatic, though not so audible, is the end-of-summer migration.
It's still warm! Why are the birds beginning to leave so soon? Well, temperature actually has very little to do bird migration. Days are shortening and so are the food supplies that these birds rely on to sustain themselves and their young all during the spring and summer. For many migrants, they have a long trip ahead of them, and there's no good reason to delay departure until food sources run low or disappear.
For the hummingbirds, orioles, flycatchers, ospreys, and broad-winged hawks (just to name a few) traveling to Central and South America, the time is now. As they move south, they will stop over and forage in locations where food is still abundant. Eventually they will reach the wintering grounds in the southern hemisphere where summer's bounty is just beginning.
In honor of the beginning of this migration that will continue well into the fall and the beginning of winter, I've posted a few of my favorite photos of birds in flight from this past spring and summer. Enjoy them and then make your way outdoors to witness the miracle of bird migration for yourself.