This is Bird Note.

Oh, Oklahoma every night, my honey lamb and I sit alone and talk and watch a hawk making lazy circles in the sky.

A red-tailed hawk soars above a roadway on broad, rounded wings, the epitome of effortless flight. Without flapping,

it traces a leisurely rising circle. This is the hawk you're most likely to see in the lower

48 and the one that was making lazy circles in the sky in the musical Oklahoma.

The red-tailed hawk is riding a thermal,

a column of warm rising air generated near the earth's surface by heat from the sun.

As the warm air expands upward, the hawk floats skyward,

periodically circling to stay within the column of air. Slots between the long feathers at the hawks

wingtips deflect drag. As the redtail reaches a desired altitude, it slides off the thermal,

and, gliding lower, finds another thermal to ride upward. Riding thermals is an energy-efficient way for soaring hawks to search for prey.

Hawks also rely on thermals and updrafts along ridges during long migrations

as they float for many miles through the sky.

For Bird Note, I'm Mary McCann.

If you know someone who might enjoy today's program, send them to our website,

birdnote.org.