988 U.S. NATIONAL MUSEUM BULLETIN 23 7 fart 2 



sparrows may fly to the top of a yucca stalk or a bare mesquite shrub 

 and sit warming themselves for half an hour or more. One cold 

 January morning, just after sun-up, eight Cassin's sparrows were seen 

 sitting on yucca stalks in a 20-acre grassy field near Midland, Texas. 

 In the afternoon, when the temperature had risen to 50°, not a cassinii 

 could be found in that same field. 



Probably because of its secretive habits, the species has never been 

 seen dust bathing. Only once was one noted in a water bath — an 

 immature bathed briefly in a puddle left by a lawn sprinkler. It sat 

 low in a shrub and preened briefly after its bath. 



Voice. — Cassin's sparrow is known for its exquisitely sweet, haunting 

 song. The song begins with two low, soft notes (seldom heard), 

 followed by a long, loud, high, hquid trill and two shorter descending 

 notes. When the male is defending his territory he gives the song in 

 flight. He flies directly upward for about 20 feet, giving the two 

 low notes as he rises. Then he sets his wings and sings as he floats 

 downward, uttering the two descending notes just before he lights. 

 As he descends, he holds his head up, his tail outspread, and his legs 

 stretched downward. He rarely begins and ends his flight song at 

 the same perch, usually traveHng 15 to 30 feet during the downward 

 sail. 



Birds that winter in the Midland, Texas area may sing on warm 

 days in early February. First-year birds sometimes begin singing in 

 March before they lose the breast streakings of their first winter 

 plumage. The species does not begin singing regularly until late 

 March. A single male in an area does not begin to sing in flight 

 until a second male enters the area. From April through July their 

 songs are heard incessantly, night and day. H. W. Henshaw (1875) 

 gives a graphic account of Cassin's sparrow's song. "It * * * pos- 

 sesses an indescribable sweetness and pathos, especially when heard, 

 as is often the case, during the still hom-s of the night. During a 

 night's march from Camp Grant to Camp Bowie, I do not think an 

 interval of five minutes passed unbroken by the song of one of these 

 sparrows. Ere fairly out of hearing of the notes of one performer, 

 the same plaintive strain was taken up by another invisible musician 

 a Httle farther on, and so it continued till just before dawn." 



Territorial songs are usually not sung from the middle of July to 

 the middle of September. September songs are not always typical, 

 and are deHvered more quietly and less frequently than earher in the 

 summer. During the late summer, a "whisper" song may be heard. 

 It is very soft, and consists of a few preliminary notes and an assort- 

 ment of trills. The song may continue several minutes, but each 

 phrase is slightly different. The bird seems to be singing to itself, 



