992 U.S. NATIONAL MUSEUM BULLETIN 23 7 part 2 



AMPHISPIZA BILINEATA OPUNTIA Burleigh and Lowery 



Guadalupe Black -throated Sparrow 

 Contributed by Richard C. Banks 



Habits 



In 1939 Thomas D. Burleigh and George H. Lowery, Jr., described 

 this form of the black-throated sparrow from the Guadalupe Moun- 

 tain region of western Texas, as being decidedly larger and slightly 

 grayer than the more eastern A. b. bilineata, with a smaller white 

 spot on the tip of the outer tail feather, and as grayer and larger than 

 the more western A. b. deserticola. This subspecies also occurs in 

 western Oklahoma, southeastern Colorado, eastern New Mexico, 

 and northern Coahuila. 



Of the status of the black-throated sparrow in the Guadalupe 

 Mountains, T. D. Burleigh and G. H. Lowery (1940) say: 



We found the desert sparrow to be a common bird here throughout the larger 

 part of the year, occurring both in the open desert and in the canyons to an al- 

 titude of approximately 6,500 feet. Its distribution during the summer months, 

 however, was limited by the presence of the cane cactus {Opuntia arborescens) , 

 and in spots where this characteristic plant was scarce or wanting, none of these 

 sparrows was encountered. This partiality was eventually explained by the 

 fact that so far as we could determine the nest was always placed in this cactus. 

 It is apparently the middle of May before nesting activities are well under way 

 and a month later before the young are fully fledged. * * * During the winter 

 months these birds desert entirely that portion of their breeding range lying above 

 an altitude of 4,800 feet, and even at this lower altitude are rather scarce at this 

 season of the year. In early January only an occasional small flock was noted 

 in the open desert * * * . 



Elsewhere in the range of the subspecies the restriction to a par- 

 ticular plant for nesting may not be as extreme. Oliver Davie 

 (1898) was apparently referring to birds that would later be called 

 opuntia: "Mr. Wm. Lloyd found it breeding in Western Texas, 

 nesting in the cat-claw or chapparal bushes. Nests were found 

 May 6 and 13, June 12, and July 13 containing fresh eggs, indicating 

 that the bird rears at least two broods in a season." Thomas H. 

 Montgomery, Jr., (1905) found it common among the mesquite in 

 Brewster County, Texas. 



At the southern extent of the range, where some intergradation 

 with the neighboring races A. b. grisea and A. b. bilineata occm's in 

 the Sierra del Carmen of northern Coahuila, nesting apparently 

 begins somewhat earlier. A. H. Miller (1955a) states that "This 

 sparrow was moderately common in the open desert scrub at the 

 base of the mountains below 4800 feet. Females taken on April 

 22 and 26 had brood patches and had recently laid." 



