NORTH AMERICAN MARSH BIRDS 105 



near their extremities. The largest sycamore in the heronry was 

 over 10 feet in girth and held 16 occupied nests, as well as several 

 old nests; the lowest nest was about 70 feet up and the highest was 

 over 80 feet. Climbing the smooth trunks of these big trees and 

 going out on the slippery limbs must test the nerve and strength of 

 the best climber. 



Walter E. Hastings has sent me some fine photographs and some 

 interesting notes, including a map showing the locations of 18 

 Michigan rookeries of gi*eat blue herons. In the colonies that he 

 has visited, the nests were usually placed in high elm trees, from 40 

 to 110 feet from the ground, near the tops of the trees or the ends 

 of the branches; often the trees or branches are dead, making it 

 dangerous to climb them. In building their nests the birds often 

 break the twigs off the trees rather than pick them up off the ground. 

 New nests of the year are often so frail that the eggs can be seen 

 through them from below. The older nests, which have been added 

 to each year, are much larger, thicker, and firmer; the accumulated 

 filth helps to cement the material together. Mr. Hastings once sat 

 in one of these nests, 110 feet from the ground, for a number of 

 hours while photographing the birds. 



On the plains and prairies of the interior the great blue herons 

 have to be contented with the largest trees they can find, cotton- 

 woods, poplars, and box elders, in the timber belts along the streams. 

 We found a colony of about 15 or 20 nests on Skull Creek, near Crane 

 Lake, Saskatchewan, on June 5, 1905. The nests were from 15 to 25 

 feet up in the tops of the largest box elders. At that date most of 

 the nests contained young of various ages, but two nests held six 

 eggs each and several others 4 or 5 each. We visited this colony the 

 following year and found that it had been shot out; the dead bodies 

 of the herons were lying on the ground under the trees and the nests 

 were deserted. 



A. D. Henderson writes me that there has been a small colony 

 near Belvedere, Alberta, since 1920. He saw "two of the nests on 

 an island in tall poplar trees in the fall of 1920." In the fall of 

 1922, he "saw six nests in a solitary spruce on another island about 

 a mile distant." On May 15, 1923, he "visited this island and found 

 five occupied nests and took one set of five eggs and one of six. The 

 nests were all on the same spruce tree and those occupied had been 

 newly built, the old nests being easily distinguished by the liberal 

 coat of whitewash on them. The nests were large structures of dead 

 sticks, fined with green alder twigs and weed stalks and a very Uttle 

 dry grass." This is the most northern colony of which I have any 

 record. 



Eggs. — Four eggs is probably the commonest number laid by the 

 great blue heron, though full sets of three are not uncommon, sets of 



