GREATER PRAIRIE CHICKEN 261 



pating were dependent upon the severity of the winter in the northern part of 

 the range. The exodus usually took place in November or December (Wisconsin, 

 Madison, November 25; Iowa, Ogden, December 14, and Osage, December 30), 

 while the return trip was made in February, March, or April (Iowa, Sioux City, 

 February 4, Marshalltown, February 7, and Osage, February 13 ; Wisconsin, 

 Unity, February 15, Elkhorn, March 2, and Whitewater, April 1 ; and Minnesota, 

 Fort Snelling, March 21, and Minneapolis, April 8). 



Thus it is clear that the prairie chicken, at least in the Northern 

 States, makes flights of considerable length, which we can consider of 

 a migratory character. In addition to these movements there are 

 shifts and concentrations of the birds that are very local and mainly 

 concerned with the food supply. At the feeding stations established 

 in Wisconsin it was not unusual for 200 to 300 birds to feed at a 

 single station at one time, a total far in excess of the numbers breed- 

 ing in the vicinity. Some of the birds may have migrated from 

 the north, but it is probable that the mass of these flocks are merely 

 aggregations from a limited region of a few counties. 



Winter. — In regions where deep snows prevail, the prairie chickens 

 often dig themselves into the deep drifts to avoid the excessive cold. 

 One observer at Green Bay, Wis., relates observing five prairie 

 chickens alight on the surface of the snow, which was about 2% 

 feet deep. The birds walked up to some weed stalks that projected 

 through the snow and then dug themselves in at places about 10 to 

 12 yards apart. A day later the same observer flushed the birds 

 from the snow bank and found well-molded places on the ground 

 among the weeds. There was an accumulation of droppings in 

 each burrow, indicating that the birds had remained in the same 

 spot during the night. The practice of digging into the snow has 

 proved disastrous at times when it becomes covered over with a 

 resistant layer of ice. 



Gale W. Monson, of Argusville, N. Dak., says in his notes: 



In winter the prairie chickens are our most conspicuous birds. They spend 

 the nights in the tall grass of marshy meadows making small pockets for 

 themselves in the snow. At sunrise they leave their beds and fly to the nearest 

 cornfield, there to eat their fill of that grain. In the afternoon they return 

 again to their sleeping quarters. Their chief enemy at this time is the snowy 

 owl, which sometimes depletes their numbers to a noticeable extent. 



Several observers in Wisconsin report that the tall marsh grass is 

 frequented by the prairie chickens as soon as the water of the swamps 

 is solidly frozen over. 



John Worden, of Plainfield, Wis., states that during times of deep 

 snows the prairie chickens are often in a semistarved condition. 

 At such times the birds showed little fear of man and often allowed 

 him to approach within a few yards before attempting to fly. A 

 farmer living near Babcock, Wis., stated that in collecting shocks 



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