Cassin's Sparrow

Thin whistles near the top of the register—or a light trill—drop into coarser, lower notes. Males can deliver this song from a perch or during a fluttering display flight.

It breeds across parts of the southern Great Plains and the Southwest, then many birds move south into northern Mexico for winter. Some populations are nomadic and shift around with rainfall and grass growth.

Look for it in arid grasslands, desert scrub, and shrubby prairie with scattered mesquite, yucca, or low bushes. It likes open country with bunchgrasses and bare patches, not thick woods.

Spring and summer are the best times to find it, when males sing from shrubs or rise into fluttering song flights. Outside the breeding season it often goes quiet, stays low, and can seem to disappear into the grass.

Cassin's Sparrow is a pale, sandy sparrow of wide-open grasslands, easy to miss until a male lifts into the air and spills out a bright, tinkling song. On the ground it looks subtle and smooth, with soft gray-brown tones and a long, rounded tail that melts into dry prairie.