BIRDS OF COLORADO. 
103 
558. Zonotrichia albicollis. White-throated Sparrow. 
Migratory; rare. The only records for Colorado of this 
eastern species are the one shot by C. W. Beckham at Pueblo, 
October 24, 1886 (Auk, IV. 1887, 120), and the one taken by 
H. G. Smith near Denver October 5, 1892. (Nidologist, III. 
1896-7, 76.) Since it has been taken as a rare migrant on the 
Platte in Wyoming and is known to breed in northern Wyoming, 
it is probable that more pass through Colorado in migration 
than would be supposed from the meagreness of the record. 
559a. Spizelia monticola ochracea. Western Tree 
Sparrow. 
Winter resident; common. Spends the winter on the 
plains and in the lower parts of the mountains. Common to 
7,000 feet and occasionally to 9,000. Arrives from the north 
about the middle of October and becomes common early in 
November. The bulk leave in April and the last by the first 
of May. The western form is found over all the plains to 
Kansas. 
560. Spizelia socialis. Chipping Sparrow. 
Summer resident, rare; in migration, not uncommon. 
The typical Chippy of the east comes into Colorado as far as 
the foothills of the Rocky Mountains. There is no authentic 
record as high as 6,000 feet. The western variety, arizoncs^ is 
the prevailing form at the base of the mountains and for seveial 
miles out on the plains. There is need of much more infor- 
mation as to the relative distribution of the two birds in eastern 
Colorado. Though not uncommon during migration, the typi- 
cal form must be quite rare as a breeder. There is indeed no 
unquestionable record of its breeding in Colorado and it is en- 
tered above as a summer resident on the strength of its known 
breeding to the east and the north in Kansas and Nebraska. 
Arrives in northern Colorado the last of April. 
560a. Spizelia socialis arizonae. Western Chipping 
Sparrow. 
Summer resident ; abundant. Especially common along 
the foothills in migration. Allen and Brewster mention a flock 
of at least 1,000 birds seen May 13 at Colorado Springs. Not 
known to breed far out on the plains, but it breeds from the 
base of the foothills to nearly 10,000 feet. Breeds most com- 
monly from 6,000 to 7,000 feet. Arrives the middle of April 
and most go into the foothills by the middle of May. Breeds 
the middle of June. Leaves the State the latter part of October. 
Six specimens taken by Capt. P. M. Thorne at Fort Lyon have 
been identified as this variety, but they are known there only 
during migration. 
