Published online by Cambridge University Press: 11 May 2010
Originally described last century from New Mexico, U.S.A., Worthen's Sparrow Spizella wortheni has subsequently been recorded from just eight states in Mexico centred on the interior of the north-east of the country. Records during the last 30 years originate from just Coahuila and Nuevo León, with those during the last 10 years exclusively from two small areas in south-eastern Coahuila and western Nuevo León: it appears that this poorly known species has been suffering a range contraction owing to the widespread destruction of its shrubby (mesquite or yucca-juniper) grassland habitat. Little detail is known of its specific requirements, local movements, or even its distribution, and it is proposed that Worthen's Sparrow be formally recognized as a threatened species.
Originalmente descrito el siglo pasado a partir de ejemplares procedentes de Nuevo Méjico, U.S.A., Spizella wortheni ha sido posteriormente citado en ocho estados mejicanos, todos en el interior del noreste del país. Durante los últimos 30 años, todas las citas provienen de Coahuila y Nuevo León, y durante los últimos 10 exclusivamente de dos pequeñas áreas del sureste de Coahuila y del oeste de Nuevo León: parece que el área de distribution de esta escasamente conocida especie ha ido reduciéndose debido a una generalizada destructión de su hábitat de matorral (mescal o yuca-enebro) pastizal. Se conoce muy poco de sus requerimientos específicos, movimientos locales, o incluso su distributión, y se propone que Spizella wortheni sea formalmente reconocido como una especie amenazada.