WORTHEN'S SPARROW 1237 



Coahiiila, in April, which was probably a migrant. My own observa- 

 tions (Webster and Orr, 1954a; Webster, 1954, 1958, and MS.) concern 

 a colony, estimated at eight breeding pairs in 1954, 9 miles northwest 

 of Sombrerete, Zacatecas, at 7,800 feet elevation on the northeast 

 shoulder of Cerro Gordo. Here the bii'ds occupied a tract of heavily 

 grazed open rangeland or grassland which was dotted with small 

 trees and bushes. Slirubby junipers {Juniperus deppeana) were the 

 chief woody plants, averaging from 15 to 35 yards apart; most of them 

 were 6 to 8 feet tall, the highest 12 feet. Other shrubs, sparsely 

 distributed, were Cowania mexicana, Acacia sp., Opuntia sp., and Pinus 

 edulis. Ground cover consisted of numerous tufts of the shrub 

 Brickellia spinulosa 6 to 12 inches high, and a sparse sod of grama 

 grass (Bouteloua sp.) and herbaceous weeds. The commonest asso- 

 ciated birds in June and July were the brown towhee, bush-tit, lark 

 sparrow, eastern meadowlark, house finch, and chipping sparrow. 



Habits. — On sunny mornings in June and early July the male 

 Worthen's sparrows sang almost continually from daylight until 

 10:00 or 11:00 a.m. One territory was 100 by 25 yards, and others 

 seemed about the same size; several shrubs or trees served as song 

 perches. Feeding was ordinarily on the ground, but once a bird 

 jumped into the air to captiu'e two flying insects and once one was 

 seen foraging in a low bush. Singing was invariably from a perch, 

 and danger alwa3's caused the birds to take refuge in a bush. Feed- 

 ing was on the territory, except that once a rival male was tolerated 

 for a few minutes whUe both fed on the one's territory. There was 

 usually no water on the nesting area in June and July, and occasionally 

 one or another bird flew off toward the creek j^ to 1}^ miles away, 

 presumably for a drink. Usually rival males were driven off vigor- 

 ously with an aerial chase and fight, followed by strong singing by the 

 victorious defender. 



Brown (in Thayer, 1925) wTites, "I found the Worthen Sparrow 

 breeding in overgrown cornfields where it nested — invariably in low 

 weeds of the mint family.* * * 



"In habits the Worthen Sparrow is almost exclusively terrestrial, 

 though during the nesting season it sings from the tops of high weeds. 

 Its song is a faint triU. In one instance I saw a Worthen Sparrow, 

 perched on a high weed, dart into the air several times after insects, 

 like a flycatcher. 



"Outside of the cornfields, in the foothills, where the land is uncul- 

 tivated and conditions are natural, this bird nests in prickly shrubs, 

 the highest being about four feet from the ground." 



Voice. — The song of the male Worthen's sparrow is sometimes a 

 trill indistinguishable to my ear from that of the chipping sparrow. 

 More often, however, there is an initial slurred-down note followed by 



