1240 U.S. NATIONAL MUSEUM BULLETIN 23 7 paet 2 



taken in April, has the aui'iculars, especially dorsally, tinged with 

 buffy brown. 



Examination of most of the extant specimens (42) of Worthen's 

 sparrows provides the following information on molts: as m the field 

 sparrow (Sutton, 1935) the juvenal body plmnage is at least partially 

 lost and replaced from July to September by an adult-looking first 

 winter plumage. I took two females in postjuvenal molt in Zacatecas, 

 Aug. 16, 1961. A scanty prenuptial molt in May, sometimes extend- 

 ing into June and even July, includes primary 1 and secondaries 1-3 

 and sometimes also primary 2 and secondaries 4-7 and 1 or 2 or all 12 

 rectrices. The postnuptial molt begins on the head in June or July 

 and extends posteriorly, probably not being completed until Novem- 

 ber. Two specimens (June 7 and July 12) showed what was ap- 

 parently an overlap of the prenuptial molt (1 rectrix and 1 tertial, 1 

 rectrix and 2 tertials) with the beginning of the postnuptial molt 

 (forehead) . 



Distribution 



Apparently Worthen's sparrow is endemic on the high, temperate 

 grasslands of northern and central Mexico, and formerly, the United 

 States border. The only definite breeding locaUties are Miquihuana, 

 Tamauhpas, and near Sombrerete, Zacatecas. However, the June 

 specimen from Silver City, N. Mex., probably represents an extirpated 

 breeding population in the United States, and the August specimens 

 from Salinas, San Luis Potosi, probably indicate a breeding colony 

 there. March specimens from Chalchicomida, Puebla, and Ojuelos, 

 Jalisco, and a December skin from Tepetate, San Luis Potosi, represent 

 our only knowledge of the winter range. 



A specimen taken Apr. 16, 1941, on the desert near Saltillo, Coahuila, 

 was either a migrant or a wintering bird. Dates on Brown's, and 

 Nelson's and Goldman's specimens from Miquihuana range from May 

 27, 1924 to July 12, 1924. Near Sombrerete, my records range from 

 June 19, 1952 and 1954 to Sept. 6, 1955. 



Two subspecies of the Worthen's sparrow are recognized : the paler- 

 colored nominate S. w. wortheni in New Mexico, Tamaulipas and 

 (in winter) Puebla; and a darker race (S. w. hrowni) in Zacatecas. 

 Specimens from San Luis Potosi are apparently intermediate and one 

 from Coahuila is unassignable to race. 



Range. — The species breeds in southwestern Tamaidipas (Miqui- 

 huana); possibly formerly to New Mexico (one record, the type 

 specimen taken at Silver City, June 16, 1884); Zacatecas (Cerro 

 Gordo). 



Recorded in Coahuila (Saltillo), San Luis Potosi (Tepetate, Sali- 

 nas), Puebla (Chalchicomula), Jalisco (Ojuelos), and Veracruz 

 (Lim6n). 



