260 Cameron, Nesting of Great Blue Heron. [tu\y 



birds, flying very low, was observed to be approaching from behind. 

 Under the impression that these were early arrivals of the Canada 

 Geese the two men stopped to watch the flock, which then swung 

 round and alighted in two divisions on the open plain. Upon riding 

 close to them it was found that the birds were not geese but herons 

 walking about on the prairie in two parties of eight and fifteen — 

 making twenty-three in all. They were engaged in feeding; it 

 was supposed upon grasshoppers. A high northeasterly wind 

 accounted for the herons flying so low. The conclusions to be 

 drawn are: (1) That this was a body of migrant herons on their 

 first flight from the Yellowstone heronry, the place where they 

 alighted being about fifty miles due south of this nesting site. (2) 

 That herons from a particular heronry do not all go south at the 

 same time; and that the young birds probably do not cover more 

 than fifty miles on the first trip, as shown by the fact that the flock 

 alighted (evidently for food and rest) despite the proximity of the 

 horsemen. (3) That herons migrate by day, and not necessarily 

 by night. 



The nests of Great Blue Herons, in Montana, are made entirely 

 of dead Cottonwood sticks, without lining of any kind and white- 

 washed by the excrement of the birds. Although at first bulky 

 structures, they are so constantly knocked about by high winds 

 and the trampling of the herons that very few retain their original 

 proportions by the time that the young can fly at two months old. 

 The dimensions of an average nest which I took were : diameter of 

 greatest width across sticks, 3 feet 2 inches; diameter of cavity, 

 16 inches. As pointed out by Mr. Seebohm, the Great Blue Heron 

 (Ardea herodias), and European Blue Heron {Ardea cinerea), build 

 their nests by placing sticks around the centre so as to form arcs,, 

 differing thus from the Night Heron, and some other species, which 

 arrange the sticks outwards from the centre so as to form radii. 

 The European Blue Heron is very much like the American species, 

 in appearance and habits excepting that in the former the tibiae and 

 border of the wing are white while in the latter they are purplish- 

 cinnamon or rufous. 1 



It would appear that Montana Herons are desirous of placing 



1 Water Birds of North America, by Baird, Brewer, and Ridgway, Vol. I, p. 5, 6. 



