Worthen's Sparrow (Spizella wortheni) in the Northern Mexican Plateau

Abstract Worthen's sparrow (Spizella wortheni) is probably one of the least known sparrows of North America. Its breeding range is uncertain, as there are questionable records from several localities in Mexico and from the type locality near Silver City, New Mexico, in the United States. Currently, the only unquestionable records are from Coahuila and Nuevo León. Here we describe new localities for this species from the state of Nuevo León and confirm already known localities from Coahuila. These new records were gathered during a bird-monitoring program within colonies of the Mexican prairie dog (Cynomys mexicanus) in northeastern Mexico. We surveyed seven grassland areas and recorded Worthen's sparrow at four of them; Los Angeles, La Perforadora, La Soledad, and El Guerrero. Our records add more detail to the known distribution of this species and our behavioral observations suggest they breed in all four localities.