Dear Bird Folks,

So we know that summer is officially over, what group of birds is the last to migrate south?

– Donna, Marshfield, MA

Good idea Donna,

I like that you want to base the seasonal changes on which birds are leaving. Most people base the passing of summer on the changing color of the leaves, the amount of daylight, or the length of the line at the ice cream shop. I usually feel summer is over when those wonderful yellow buses take the kids back to school, where they belong. Or when the town stops charging $35.00 an hour to use the beach parking lot. (Believe me, I’m not being critical of parking lot fees. As long as the money is used to keep the school buses running, I’m all for it.)

Fall is obviously the time of a great bird migration. Birds of all shapes and sizes get out of town while the getting is good and before the getting is not so good. Which bird signals the end of summer depends on where you live and which species of birds you pay attention to the most. Here on the coast, many birders look forward to seeing the large flocks of terns staging up before they head south. Most backyard bird watchers on the other hand don’t even notice the terns. They are too busy counting down the days until the grackles leave.

Other people feel that summer is over when the orioles and hummingbirds stop showing up at their feeders. When the weather turns cooler they go out and collect their sugar water and jelly feeders. They give them a good cleaning and put them away in a special location that they will totally forget about when spring returns.

For me, two species of birds signal the end of the summer. The first birds that I notice packing up to leave are the Tree Swallows. Somewhere around mid August I begin to see a dozen or so of these handsome green and white birds resting on the power lines. Seeing the swallows form into small flocks is a sign that if I can just hang on a few more weeks I might actually make it through another Cape Cod summer.

Forming a small flock is just the beginning for Tree Swallows. Some birds, such as the kingfisher, hate each others company. They migrate alone and like it that way. Other birds, particularly waterfowl, feel very comfortable being with their friends. They usually head south in flocks that may number in the hundreds. But when it comes to finding friends to migrate with it’s hard to top the Tree Swallow. During migration Tree Swallow flocks can reach into the hundreds of thousands.

The east coast is a major flyway for Tree Swallows because they are one of the few birds that are able to eat the fruit of the bayberry bush. If the insects aren’t flying the swallows will chow down on the fragrant bayberries, which also explains why Tree Swallows are our best smelling swallow. Towards the end of every summer I receive dozens of calls from beachcombers who come upon one of these huge flocks of swallows. Some callers are in a state of panic, thinking that the end is coming. In a way they are right, the end is coming, the end of summer.

The other bird that signals the end of summer for me is much less spectacular in its migration. It is the endearing Gray Catbird. One of my favorite things to do when I get out of work, after a long day of listening to people complain about squirrels, is put on a pair of Rollerblades and skate the Cape Cod Rail Trail. I go out late in the day to avoid the heat of the sun and the constant cameras of the paparazzi. Since it’s late in the day most of the birds have quieted down, but not the catbirds. Even at dusk they fly back and forth across the trail picking up insects or fallen berries. Even after they have stopped feeding, their signature “meow” call can be heard in the growing darkness.

The catbirds must really like it here because they are one of the last to leave. Eventually they head south too and I have the bike trail all to myself.

Every birder has their own indicator of the changing seasons, Donna. The Tree Swallows and the Gray Catbirds just happen to be mine. Without them the skies are emptier and the bike trail is quieter. But the changes that cause the summer birds to move out also brings a new group of birds, the winter birds. Here on the coast our winter visitors include gannets, eiders and mergansers. And if we are all good, we’ll get a visit from the best winter visitor of them all. Yes, I’m talking about Santa. Maybe this year I’ll finally get those new Rollerblades I’ve been asking him for. I can’t wait.