926 U.S. NATIONAL MUSEUM BULLETIN 237 part 2 



June 10. A female from the latter group had a tail measuring 30K 

 millimeters. 



Other early breeding records in Arizona are as foUows: a juvenal 

 female, tail 65 millimeters (nearly fuUy grown), was taken in the Santa 

 Rita Mountains, May 23, 1940 (Sutton, 1943; tail condition fide 

 Richard R. Graber, MS.) ; at Aravaipa Creek near Klondyke, Graham 

 County, J. S. Rowley (MS.) took a juvenal (tail 18 milUmeters) on 

 May 30, 1936; and Seymour H. Levy (MS.) found a nest with three 

 eggs in the southeastern corner of the state May 13, 1960. 



The total rainfall in years when early singing or nesting was re- 

 corded was not necessarily exceptional. Thus in the winters of 1938- 

 39 and 1939-40, rainfall at Tucson was below the mean (calculated 

 arithmetical average) in every month from October to April, except 

 February; rainfall was particularly low in 1939-40, when the total 

 October-through-January rainfall barely exceeded the February 

 total of 36 milhmeters and March and April jdelded only 9 

 millimeters. 



The winters of 1906-07 and 1935-36 followed a different pattern. 

 Rainfall was well above normal in December and January (1906-07) 

 and November and December (1935), dropping gradually to below 

 mean figures in February 1907 and March 1936, but never seriously 

 below the median rainfall after October. Thus proper, moist eco- 

 logical conditions in February or March seem to produce the occasional 

 April nests, regardless of the preceding rainfall. 



In Mexico the unusually early nests in some years are obviously 

 attributable to the early start of the summer rains, as most of the 

 country has no winter rainy season. Thus W. J. Schaldach, Jr., took 

 a female with a greatly enlarged ovary in Jalisco on May 10, 1959, a 

 year when the rains began 2 months early (in mid-April), and I took 

 another on May 15, 1959, which had apparently started an unsuccess- 

 ful nest as its oviduct was swollen and its ovary contained what 

 appeared to be a corpus luteum. 



Nesting. — The rufous-crowned sparrow commonly nests on the 

 ground, usually near or under a clump of grass, sometimes at the foot 

 of a sotol or a sapling. W. E. D. Scott (1886) describes the nest as 

 "very bulky for so small a bird * * * loosely and carelessly put 

 together * * * of coarse, dried grasses throughout * * * no attempt 

 at lining with any finer material. The interior diameter is two and 

 three-quarters inches, and the interior depth one inch and a half. 

 The walls are about one inch thick, but in places the grasses are 

 allowed to straggle about in so careless a manner that the walls seem 

 at least two inches in thickness." G. M. Sutton and A. R. Phillips 

 (1942) report a nest lined with deer hair. I know of no nests of 

 scottii found above ground level (see A. r. eremoeca, above) . 



