Wings: Shapes and Spans
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.
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.
- describe the basics of flight
- describe and explain wing-shape and -span of raptors and the varying uses
for their survival
Paper Raptor Designs . . .
Begin by simultaneously dropping a flat piece of paper (unfolded) and
a piece of paper that has been folded in quarters crosswise. Ask students
to observe which piece of paper drops more slowly, and why?
- make two paper raptors (see Paper Raptor Designs)
- predict how each will fly, and why
Then allow students to fly and observe their paper raptors outside or
in a gym, if possible. Be sure to inform students to observe and compare
the designs for:
- time aloft (in the air)
Then enter into some discussion about what students observed, and clarify
Activity © Hunters of the Sky by S. Thoermer ed., 1994.
Educational Resources at the Science Museum of Minnesota, St. Paul, MN.
Reproduced with permission.