Rather large sparrow with flat head and long bill. Dull brownish overall with darker streaks on back; subtle head pattern with slightly darker crown and eyeline. Primarily a Mexican species with two populations, both of which barely enter the U.S.; western birds brighter than eastern birds. Prefers grasslands with some shrubs. Shy, but perches conspicuously when singing. Similar to Cassin's Sparrow; note flatter head, longer bill, lack of eyering, and voice. Gives a series of sharp varied chips and a fast trill; much different than Cassin's sweet song.