CLAY-COLORED SPARROW 1195 



John Lane reports that of 34 nests (firsts and renests) found near 

 Brandon, Manitoba, in 1960, 14 (41.2 percent) were successful. Two 

 of the nests produced no eggs, 2 nests were destroyed, 8 abandoned, 

 and 10 rifled. Of 90 eggs found in 31 nests, 59 (65.6 percent) hatched; 

 34 young fledged, giving a reproductive efficiency of only 37.7 percent. 

 The hatching and efficiency percentages are probably inflated because 

 in nine successful nests 12 cowbird eggs or young (to some extent prob- 

 ably replacements of clay-colored eggs) were already in the nests 

 when found. In 11 nests not parasitized by cowbirds success was 

 greater; 6 (54.5 percent) were successful. Of 40 eggs, 28 (70.0 percent) 

 hatched, and 19 fledglings were produced, a reproductive efficiency 

 of 47.5 percent. Neither human interference, storms, floods, nor 

 droughts was a factor aflFecting nesting success near Brandon. L. H. 

 Walkinshaw (1944a) writes that young left from only 10 of 19 nests, 

 or 52.5 percent, near Lovells, Mich., where none of the nests suffered 

 from cowbirds. Of 56 eggs found in 19 nests, 41 (73.2 percent) 

 hatched; 30 young fledged, for a reproductive efficiency of 53.6 percent. 



Near Edmonton, Alberta (Salt, 1966), nestling losses were consider- 

 ably lower than egg losses. Of 11 nests in which 38 young hatched, 

 only two nests suffered losses. A loggerhead shi-ike took five 

 nestlings, and one died from parental desertion. 



Young. — At hatching, the body and legs are flesh colored, and 

 the skin covering the eye appears bluish-black (Walkinshaw, 1939). 

 Weight for 1 1 individuals at hatching varied between 1.1 and 1 .4 grams, 

 averaging 1.2 grams; at 8 days around 10 grams (L. H. Walkinshaw, 

 1944a). 



G. A. Fox (1961) describes the rictal area as white, and the mouth 

 lining a bright orange-red with black and yeUow palate. On the 3rd 

 and 4th days the mouth lining darkens, and the rictal area turns 

 yellow. The tarsus averages 6 millimeters at hatching and 16 milli- 

 meters on the 5th day. At one day the alar, humeral, caudal, spinal, 

 and ventral tracts show as dark dots beneath the skin. G. C. Kuj-ava 

 describes the bill of a newly hatched bu'd as cream-colored; a day 

 later the biU turns light brown in the central region, remaining cream- 

 colored around the edge. 



Both adults brood the young. G. A. Fox (1961) gives the distribu- 

 tion of brooding time during the 2nd day at a nest in Saskatchewan 

 between 1:45 and 3:45 p.m. on June 22 as: female 71 percent, male 9 

 percent, young uncovered 20 percent. 



L. H. Walkinshaw (1944a) shows in tabular form the results of four 

 periods of observation at two nests. Direct feedings of eight nesthngs, 

 ranging in age from 1 to 6 days, averaged 16 per hour by both parents 

 from 4:45 to 6:50 a.m., and 6.85 to 9 feedings per hour by both 

 parents from 8:00 to 10 a.m. On one occasion the male came in to 



