I often lose control of my brain. For instance, a couple of weeks ago I saw a flock of small birds fly across the interstate. Without my permission, my brain wandered off on its own. It wondered, how tight is the flock? Is the flight bouncy?
The birds were silhouetted against a gray sky. No colors or field marks were visible, but my brain didn’t care.
It was trying to figure out whether they were waxwings, finches, starlings, or something else, based purely on behavior. If a single bird crosses the highway, there are hundreds of possibilities. If a small flock of birds crosses the highway, there are fewer than a dozen candidates, because not many species fly in flocks.
On Monday, it happened to me again. A small hawk flashed across the road. My brain escaped into a sea of immediate questions. How did it fly? Was it the flap-flap-glide flight of a sharp-shinned hawk or the more direct flight of a merlin? How pointed were the wings? How long was the tail? Since most merlins migrate south, what were the odds of one lingering?
Unbidden, my wandering mind answered itself. The flight was fast and direct, the wings were pointed, the tail short, and the odds of a winter merlin were slim but not zero. I see one or two merlins every cold season, including this one.
I can’t stop my brain from doing this. There comes a time in every birder’s life when their identification skills move beyond a mere assessment of shape and color, and they begin to evaluate behavior.
Eventually, it becomes an unstoppable, ingrained habit.
Every species has a collection of adaptations that allows it to occupy a biological niche. These adaptations affect how each bird flies, walks, feeds and perches. They provide a wealth of identification clues. For instance, woodpeckers, brown creepers, black-and-white warblers and nuthatches are all able to walk up a tree trunk, but only nuthatches can walk down.
Many adaptations are mutually exclusive. Wings cannot be both big and fast. Large wings allow a bird to soar high and glide far. An albatross can spend days in the air, riding the wind. But it can never beat those big wings fast enough to be speedy. The buteo family of hawks has large wings and short tails.
Examples include broad-winged, red-shouldered and red-tailed hawks. They soar slowly, or perch and pounce. They may generate speed in a dive, but they’ll seldom outpace prey in a level flight.
Falcons have sleek, pointed wings. They are built like jet fighters, and they fly that way. Sharp-shinned hawks are members of the accipter family and have short, rounded wings and long tails. Their short wings allow them to fly fast, though not as fast as the pointy-winged merlins. The sharp-shinned hawk’s longer tail allows it to steer more quickly, outmaneuvering its quarry. Because they don’t have the large wings of a red-tailed hawk, sharp-shinned hawks are less efficient gliders, and they need to flap more frequently in order to maintain momentum. Thus, their cruising style is often described as flap-flap-glide.
Finches and waxwings are capable of flying long distances, but usually in short bursts, landing often. As a result, they don’t need the longer wings required to migrate across seas. Their shorter wings are more convenient for flitting around treetops, while munching on seeds and berries. It is also more efficient to fly in short bursts of flapping, which gives them a bouncy, undulating flight. Finches and waxwings often fly in flocks. Woodpeckers have short, stiff wings, and they have a similar undulating flight, but they seldom fly together except with immediate family.
Finches tend to have tight flocks. Waxwing flocks tend to be a little looser. Starlings fly in flocks, but often have stragglers.
It took a long time for my brain to learn these behaviors, and it took even longer to reach the point where it thinks unthinkingly.
If you’re looking around for a New Year’s resolution, I would suggest paying attention to how birds behave in 2015. Start simply. Watch how they feed. On the ground? Low bushes? Tree tops? Do they approach the bird feeder boldly or cautiously? All of these are clues.
Examine common birds. Robins and blue jays are similar in size and often fly at treetop height. They frequently alight in the upper branches. Can you see a difference in how they fly? On average, which one is faster?
Hint: It’s not the blue one.
Bob Duchesne serves as a Maine Audubon trustee and vice president of its Penobscot Valley Chapter. Bob developed the Maine Birding Trail, with information at mainebirdingtrail.com. Bob can be reached at duchesne@midmaine.com.