Worthen's Sparrow Spizella wortheni

Very local, scarce, and endangered small sparrow of desert plateau in northeast Mexico. Mainly found in rolling, short-cropped grassland (especially prairie-dog towns), with scattered yuccas and junipers. Forms flocks in winter, mixing readily with other small, rather similar sparrows such as Chipping and Clay-colored sparrows. Note the pink bill, rusty cap, whitish eyering, and dark legs.