EASTERN WHITE-CROWNED SPARROW 1275 



better sites nearby, white-throated sparrows nested. An awareness 

 of such temporary ecological changes in distribution allows me to view 

 with interest the nesting reports of white-crowns at North Bay, 

 Ontario, and at Baie Comeau and Godbout on the north shore of the 

 St. Lawrence, as well as near Godthaab, Greenland, in 1824 (Salo- 

 monson, 1950) ; though I cannot credit them for lack of corroborative 

 details on the ecology of the site. 



Despite the fact that it was the first known and is the most widely 

 distributed race, the eastern white-crown has been one of the least 

 studied. No one has yet reported in any detail on the biology of the 

 alpine populations of the Rocky Mountain massif, and the eastern 

 group has only recently begun to attract the attention it deserves. 

 In a study of geographic variation in the entire leucophrys group, 

 Richard C. Banks (1964) reduces Harry C. Oberholser's (1932) 

 Cordilleran race oriantha to synonymy with the eastern race, discounts 

 W. E. Clyde Todd's (1953) proposal of the name nigrilora for the 

 "ultratypical" Labrador peninsula population, and considers the 

 slightly larger, reddish-backed and black-lored nominate leucophrys 

 to be the ancestral population. "The species," he writes, "appears 

 to be essentially a northern one which has extended southward only 

 where summer conditions approximate those found in subarctic 

 regions. Thus, in the western * * * United States, White-crowns 

 are found only in high mountains and along the cool Pacific coast." 



Spring. — The interaction between internal and external factors 

 in the eastern population remains almost unreported. Only Marshall 

 B. Eyster (1954) has shown that, compared to such congeners as the 

 white-throated sparrow and the junco, the white-crown is much more 

 prone to pre-migratory nocturnal unrest (zugunruhe) . 



Viewed from the central wintering grounds of the southern Great 

 Plains, the spring migration involves a radiation northward. One 

 population segment goes northwestward into the Rocky Mountain 

 uplands, another more or less due north to the Cypress Hills of 

 Saskatchewan and the Hudson's Bay country, but the largest segment 

 trends far to the east of north, to summer in northern Quebec and 

 western Newfoundland. 



In an analysis of 198 recoveries and 9,107 returns from nearly 

 232,000 white-crowns banded between 1920 and 1963, Angelo J. 

 Cortopassi and Richard L. Mewaldt (1965) show that migration is of 

 a broad-front type and not oriented to landmarks — of 6,000 birds 

 banded while on migration, not a single individual returned to the 

 place of banding. Migration is by hops of at least 200 miles, with 

 one 310-mile hop recorded in spring, and with a daily mean of about 

 50 miles. One bird banded by Ralph K. Bell at Clarksville, Pa., 



