SWAINSON'S HAWK 223 



appeared to be numbers beyond, I saddled my horse in order to reconnoitre 

 further. * * * Having ridden round the fence I found that not only were 

 the trees filled with clusters of buzzards, but that the ground below was cov- 

 ered with them sitting in rows among the cattle, the sight surpassing anything 

 I had hitherto seen in bird life. All were obviously worn out and appeared 

 asleep ; but those on the ground, if closely approached, were not too tired to 

 fly up and join their comrades in the trees. * * * j gave the estimated 

 number of buzzards at about a thousand ; but it became obvious afterwards 

 that two thousand would have been nearer the true count, as twenty trees 

 each containing fifty birds give a total of a thousand without including all 

 those on the ground and in more distant cottonwoods. 



Nesting. — My experience with the nesting habits of Swainson's 

 hawk has been mainly in North Dakota and Saskatchewan, where I 

 recorded in my notes some 25 nests. Of the four nests found in 

 North Dakota in 1901, two were in timber beUs or groves of large 

 trees near Stump Lake; one of these was 40 feet from the ground 

 in the main crotch of an elm, near the top; the other was only 15 

 feet up in a leaning swamp oak on the edge of the woods next to the 

 lake. Another was only 8 feet from the ground in a small tree on the 

 open shore of the lake. And the fourth was 14 feet up in a slender 

 little Cottonwood, hardly strong enough to bear my weight, in a lit- 

 tle tree claim near a ranch. 



In southwestern Saskatchewan in 1905 we found 13 nests, eight of 

 which were found in a one day's drive up Maple Creek. In the same 

 region the following year we found eight nests, two of which were 

 the same nests used the previous year. Most of these nests were in 

 the timber belts along the small streams, where the trees were small 

 or of moderate height. They were placed in cottonwoods, other 

 poplars, willows, or boxelders, mostly at about 20 feet above the 

 ground ; one Avas 35 feet up, and some were as low as 10 or 12 feet. 

 One was only 7 feet up in a clump of small willows near Crane Lake. 

 Another was on a shelf of a cutbank in open country. Perhaps the 

 most interesting nest of all was in a little patch of large bushes on a 

 steep hillside; it was a very large nest, resting on the ground, held 

 in place by the surrounding bushes and built up to a height of 4 feet 

 on the outer side, but level on top ; our driver told us that it had been 

 in use for several years. One nest was found in a solitary poplar 

 on an open plain (pi. 63). 



Many of these nests were in commanding situations, and practi- 

 cally all of them were so located that the incubating bird could have 

 a good outlook. They were typical Buteo nests, made of large sticks, 

 finished off with twigs, weeds, or grasses, lined with inner bark and 

 fresh green leaves, often attached to the twigs, from the surrounding 

 trees; many were decorated with the flower clusters of willows, or 

 other trees, with lichens and with down or feathers shed by the hawk. 

 The measurements of several nests varied from 21 to 28 inches in 



