196 BULLETIN 196, UNITED STATES NATIONAL MUSEUM 



Bicknell's thrush the gray-cheeked can be distinguished only by size, 

 a poor field mark. 



Enemies. — All thrushes have plenty of enemies among the numerous 

 predators, but few have the kind that persecute the gray-cheeked 

 thrush on its breeding grounds. Dr. Nelson (1887) writes: "As soon 

 as the breeding season is over they become less retiring and frequent 

 the vicinity of villages and more open spots, where many are killed 

 by the native boys, armed with their bows and arrows. Their skins 

 are removed and hung in rows or bunches to dry in the smoky huts 

 and are preserved as trophies of the young hunters' prowess. In the 

 winter festivals, when the older hunters bring out the trophies of their 

 skill, the boys proudly display the skins of these thrushes and hang 

 them alongside." 



Dr. Max Minor Peet (1908) mentions one that was killed at Isle 

 Roy ale, Mich., by flying against a lighted window at night during 

 a storm. 



Only one louse, Myrsidea incerta (Kellogg), is reported by Harold 

 S. Peters (1936) as an external parasite of this thrush. 



Fall. — Gray-cheeked thrushes leave their northernmost breeding 

 grounds by the last of August, or early in September, and travel 

 southward over much the same routes that they traversed in spring, 

 which covers practically all of Canada and the United States east of 

 the Rocky Mountains. Dr. Wallace (1939) remarks that "apparently 

 not even the Alaskan and Siberian inhabitants migrate along the 

 Pacific coast. Habit is deeply intrenched in such migratory species; 

 otherwise the Siberian representatives might better winter in south- 

 ern Asia than to retrace their flight across the intercontinental 

 peninsula, and migrate the whole length of North America to winter 

 in South America." 



Ludlow Griscom (1932) records it as "migrating along the outer 

 islands of the east coast of Central America, very rare or casual on 

 the mainland (4 records only)." But Dr. Wallace (1939) says: "Of 

 the ten or more Central American records for this form only three 

 appear to be from these outer islands, and two of these are of doubtful 

 identity. Apparently they migrate over all the available routes to 

 South America, by way of the West Indian chain of islands, along 

 the Florida peninsula and across Cuba, by the outer islands along the 

 eastern Central American coast, and particularly over Central 

 America as a whole." 



We seldom think of thrushes as migrating in flocks, but, at Isle 

 Royale, Mich., Dr. Peet (1908) found these thrushes very abundant 

 in September: "Large flocks were seen every day throughout the 

 remainder of our stay [Sept. 12 to 22], the border of clearings and the 

 roadways being the places where they were the most abundant." 



