418 U.S. NATIONAL MUSEUM BULLETIN 23 7 part i 



Enemies. — The redpoll is preyed upon by the usual enemies of 

 small birds, the raptores in particular, but specific information is 

 meager. Grinnell's (1947) extensive survey of the literature revealed 

 occasional predation by falcons, harriers, and jaegers. The ani- 

 mosity the redpolls bore the northern shrike and the hawk owl at 

 Indian House Lake indicates that these, too, prey upon them even 

 though no actual chase was witnessed. Near human habitations the 

 redpoll's tameness sometimes makes it easy prey for cats (Wetherbee, 

 1937). 



Losses incm'red during the reproductive period are more impor- 

 tant, though at a level normal for small birds. Grinnell's (1943) 

 study of a total of 33 eggs showed successful hatching of only 72 per- 

 cent, and nestling losses reduced the survival of chicks at nest-leaving 

 age to 39 percent. Despite these losses, the redpoll is a common 

 bird in its own territory. 



Field marks. — The recent generic lumping by some authors of the 

 redpolls with the goldfinch and siskin and, in Europe, with the twite, 

 serin, and linnet emphasizes their similarities in form and behavior. 

 In America, except for the darker, yellow-flashing siskin, a small, 

 streaked, grayish-brown, fork-tailed finch is a redpoll; the red fore- 

 head and black chin make identification specific. Some, but not aU, 

 males have a rosy breast. The species ^ammga may be told by its 

 brownish tone, since most feathers have a buft' edging, and by the 

 streaked rump; the congeneric hornemanni group have frosty-white 

 feather edgings, and an unstreaked rump for the most part. Even 

 so, excellent observation conditions are required to separate the two 

 species, and field identification of subspecies is unsafe. Indeed, the 

 redpolls await a thorough monographic revision. 



Fall and winter. — August sees the redpolls wandering about the 

 brushy semibarrens in small family groups, slowly aggregating into 

 loose flocks, so that by September the first migrants begin winging 

 southward or to more sheltered localities. At Indian House Lake 

 throughout October there was a distinct southward flight up the valley 

 of smaU flocks of 5 to 60 birds. These birds flew directly and purpose- 

 fully, 30 to 50 feet overhead, and showed a preference for the narrow, 

 semiwooded intervale that extends for miles along the lake. They 

 caUed continuously as they flew southward upstream, their high note 

 being heard long before the birds came into sight against the usual 

 autumn background of low, ragged clouds. By whistling almost any 

 long-drawn note it was usually possible to make them veer from their 

 course and pass overhead. They seldom alighted though, and when 

 they did, it was at some distance, and they took off again immedi- 

 ately if I approached them. This flight was a conspicuous feature of the 



