CASSIN'S SPARROW 985 



needle cactus (Opuntia leptocaulis P.D.C.), small evergreen shrub 

 or bush, or in bunch of grass; rarely up to one foot in low bushes." 

 A nest we found near Midland, Texas was in an Opuntia leptocaulis 

 growing in the middle of a small mesquite bush. The bottom of this 

 nest was 6 inches from the ground, and the rim was 8)2 inches from 

 the ground. 



The cup-shaped nest is composed of weedstems, dead grass, and 

 rarely, flowers. It is lined with fine grass, rootlets, grasstops, and 

 sometimes a little horsehair. A nest near Midland, Texas was 

 constructed entirely of grass with the thicker stems on the outside 

 and finer grass on the inside. The outside diameter at the rim was 

 4 inches, the inside diameter 2% inches. The inside depth was 

 2 inches. 



A nest Herbert Brandt (1940) found was "Deep in the heart of 

 [a] * * * cactus * * * a tiny, well-concealed nest that could be 

 found only by taking apart the protecting pad. * * * It was rather 

 bulky, and composed of grass, with a lining of finer grasses, horsehair, 

 and some red cattle hair." 



The nest described by L. J. Hersey and R. R. Rockwell (1907) 

 near Barr, Colo., 



was a neat structure when supported by the numerous stems, but when removed 

 proved to be rather flimsy in construction and very fragile. It was composed 

 entirely of dry grass blades and stems, weed stems and barks, and vegetable 

 fibers, lined with fine grass blades and a very few fine grass stems. The nest 

 was unusually deeply cupped, with the sides built perpendicularly and slightly 

 rimmed in. It measured as follows: outside, 3J4 inches in height, 4 inches in 

 long diameter, and 3K inches in short diameter; inside, depth of nest cavity from 

 rim of nest 2]^ inches, short diameter 2 inches, and long diameter 2)2 inches. 

 The circumference of the inside of the rim was slightly less than that of the cavity 

 where the eggs lay. The rim of the nest was not symmetrical but varied in height 

 and thickness to conform to the branches among which it was placed, and altho 

 built near the outer edge of the bush was supported and concealed on all sides by 

 the spreading branches of the plant, which was about 10 inches high and 18 

 inches in diameter. 



Eggs. — Cassin's sparrow lays usually four, but sometimes three 

 or five eggs. The eggs are nearly oval, but somewhat elongated. 

 They are white, unspotted, slightly glossy. The measm-ements of 

 44 eggs average 19.0 by 14.6 millimeters; the eggs showing the four 

 extremes measure 20.9 by 15.4, 18.9 by 13.6, and 17.8 by 13.0 milli- 

 meters. 



Young. — The incubation period for Cassin's sparrow is unknown. 

 The parent birds forsake their nest for the slightest cause. Many 

 observers returning to a pre\'iously discovered nest have found it 

 deserted and the eggs gone. 



Both parents feed the nestlings. At a nest near Midland, Texas 

 the young were fed small moths and catei-pillars up to 2 inches in 



