SNOW BUNTING 1669 



According to Scholander et al. (1950a, 1950b) snow buntings under 

 cold stress can tolerate —40° F, but at —58° F their body tempera- 

 tures drop seriously within an hour. Thus at very low temperatures 

 the birds must depend on behavioral thermoregulation to some ex- 

 tent, and particularly to avoid windchill which must often be a hazard 

 to them. A. M. Bagg (1943) reports their burrowing into snowdrifts 

 during —35° F weather in Massachusetts and remaining huddled in 

 their individual holes throughout the day, emerging "only occasionally 

 to feed on a nearby chaff pile." Salomonsen states: "The birds in a 

 flock have often a common roosting-place in which they spend the 

 night, as a rule in cavities or crevices in rocks, in which they crouch 

 close together in order to take shelter against the cold of the night." 



Witherby et al. state "Roosts, sometimes singly, but often in 

 parties, in shelter of stones, clods, grass-tussocks, etc., on ground; 

 also recorded in quarry." Forbush (1929) writes: "When the snow 

 is soft, these birds are said to dive into it (as they do sometimes when 

 pursued by hawks), and there pass the night. When the snow is 

 frozen hard, the flocks sleep in the open, protected from the north 

 wind only by some slight rise in the ground, by sand dunes, or by a 

 stone wall. * * * Snow Buntings are necessarily very light sleepers; 

 when caged, they are said to be always awake and moving, when 

 approached in the night. The wild birds leave their resting place at 

 the first hint of light in the east, and begin feeding while it is still 

 quite dark. They have never been known to roost in trees at night." 



Roosting during the winter and at low latitudes probably coincides 

 with and is governed by the hours of darkness. Conceivably in the 

 continuous daylight that shines on much of their northern breeding 

 grounds the birds might stay awake and active indefinitely, but they 

 usually go to roost and sleep part of each day, usually when the sun 

 is lowest. Tinbergen found that in southeastern Greenland the 

 buntings "awoke earlier from day to day during April, until at the 

 beginning of May their activities started at about 1 A.M. Although 

 the nights grew lighter until the end of June, the birds did not rise 

 any earlier from about the middle of May onward; a certain amount 

 of sleep, about 2 to 3 hours, apparently is necessary." 



Roosting behavior on the high northern breeding grounds has not 

 been widely reported. The following paragraphs are adapted largely 

 from the account MacDonald and I prepared of our observations near 

 Slidre Fiord in west-central Ellesmere Island between April 16 and 

 September 27, 1955. 



When the first male buntings returned to Slidre Fiord, apparently 

 the same day we arrived there, the sun was continuously above the 

 horizon. When it was low these early arrivals roosted at Eureka 

 Weather Station in a lumber pile, as many as 28 of them at once. 



