Bird tails offer telltale clues for identification
Bird tails tell tales that help us clinch a bird’s identification. The tail’s shape and hues, as well as the way the bird holds its tail, are identifying characteristics.
A good example is the tail of a greattailed grackle, which immediately identifies the raucous, black-feathered bird. A long, black, keel-shaped tail thrust out like a rudder enables a grackle to dart around city streets and buildings.
We’d recognize a northern mockingbird flying frenetically through our yard, flashing bold white outer tail feathers on an otherwise long gray tail. When perched, the mockingbird cocks its tail upward at an angle as if boasting about its prowess.
The similar-looking loggerhead shrike also has a long tail with white outer feathers. But it makes speedy, direct flights from perch to prey, rarely in a frenzy. When perched, the shrike cocks its tail downward, as if nonchalant about its menace.
Both birds deliberately flash their white outer tail feathers along with white wing patches. The purpose isn’t clear. Perhaps the birds flash white to spook up insects camouflaged on the ground.
But watch a mockingbird at a bird feeder. It will quickly flash those white tail feathers in a threat display to ward off another mockingbird intruding on its feeding station.
Both a mockingbird and shrike will spread their white tail feathers to warn about predators, such as a cat or a snake. Tail flashing also warns people to stay away from a nest.
Bird tails also provide support and balance. Woodpeckers use their stiff tails
to brace themselves against tree trunks. Brown thrashers use their long tails for balance as they skulk through the lower branches of bushes and shrubs.
A bird’s tail is essential in flight. It provides aerodynamic lift for a major portion of the bird’s body, since the wings are positioned slightly forward of the body’s center of gravity. The tail also acts as a rudder to steer flight, change altitude and facilitate takeoffs and landings.
Watch a red-tailed hawk flying overhead. It will slightly twist its tail to change direction and fan its tail to soar in wide circles. The hawk will flutter its wings to hover in midair, like a helicopter, and then fold the tail into a narrow shaft before swooping down to nab a rat.