Birds of Prey: Activity - Wings: Shapes and Spans

Background

Hawks, owls, eagles, and falcons have many different wing shapes, depending on the kinds of animals they hunt and the habitat in which they live.

For example, the falcon (e.g. peregrine) relies on its wing shape and speed to catch other birds and literally grab them out of the sky. For this bird, a narrow, pointed wing is perfect - drag is kept to a minimum and the swept-back wing design allows them to dive at speeds over 100 miles per hour.

However, the wing shapes of hawks, eagles, and vultures are designed to ride the winds. Their wings are much wider with long, slotted wing feathers that can be opened to keep airflow smooth and prevent stalling at slow speeds. This allows the birds an advantage in scanning the ground or water below, watching for movement that signals the presence of prey.

Warm air is lighter than cold air. And as the sun heats the earth, it sets up warm air currents, or thermals, that rise from the ground. Eagles, hawks, and vultures use their broad wings to soar upward on these thermals. When they reach the top of a column of air, they launch out on a long glide to the next thermal, where they circle upward once again. Without their long, broad wings, they would not be able to soar.

Woodland (forest) hawks have shorter wings and longer tails to allow quick, tight turns among the trees. However, the trade off is that they must do more flapping, and are recognized by their typical flap-flap glide pattern of flight. They spend less time in the air than soaring birds, and usually hunt from a perch. Their short, broad wings allow for quick, steep takeoffs.

Owls have long, broad wings with flight feathers that are frayed on the edges to muffle sound and allow silent flight. This is an advantage to a night hunter who must sneak up on its prey without being heard.