The Cassin’s Sparrow is a year-round resident in southeastern Arizona, southern New Mexico, most of Texas’s western sections and much of Mexico. They prefer arid brushy grasslands. In the breeding season, the males perform an aerial display called “Skylarking”, where they fly to great heights and float down on stiffened wings, singing the whole time.
The population of these birds varies widely in some regions from year to year. The absence or abundance of rainfall is believed to affect the seasonal population.