NATURAL HISTORY SOCIETY OF GLASGOW. 267 



38. Circus Imdsonicus, Vieill. — Marsh Hawk. 



Nest of 6 eggs. "Taken 16/5/70, in Madison, Conn., by 

 myself. I first discovered their haunt about the beginning of 

 May. They were flying about in an erratic manner, which led me 



to think that they were nesting in the vicinity I 



succeeded in finding a bog suited to their purpose, and revisited 

 the place a few days after : on this latter occasion I started the 

 female off the nest. The nest was situated near the edge of the 

 bog, on the ground, and composed of a quantity of sticks, upon 

 which was piled a lot of coarse grass, such as was growing in 

 abundance all about the nest. There was but little skill or taste 

 displayed in the construction. From the fact that the materials 

 at the bottom of the nest were quite rotten, I concluded that it 

 was an old nest repaired, by simply placing on more grass. The 



nest then contained 1 egg Both hawks were circling 



overhead. On the 14th May the nest contained 5 eggs; but not 

 feeling satisfied with that, I left it two days longer, when I found 

 6 eggs, which I think is the number usually laid. On rising from 

 the nest, the female would circle round overhead, and the 

 male would soon afterwards join her; showing that he must 

 have been in the immediate vicinity." Mr Jones describes 

 another nest " in a bog, not over 30 rods from the public 

 highway, and in full view, and composed of sticks, without 

 any lining." Mr Jones further notes, that — " This hawk is 

 generally seen flying very near the ground, searching for food, 

 which consists principally of field mice." He also relates how, 

 upon one occasion, he saw one settle upon a tree; which he 

 considers unusual. 



This species is closely related to our well-known Hen Harrier 

 {Circus cyaneus, Lin.). On comparing these 6 eggs of C. hudsonicus 

 with a series of 22 Scotch-taken eggs of C. cyaneus, I find them 

 smaller than 20 of the latter — by actual measurements — and larger 

 than only 2. These two are Hebridean specimens, and measure 

 respectively, If in. by 1§ in., and If in. by rather less than If in.; 

 and the average measurement of the largest set of 6 eggs of 

 C. cyaneus are 1\% in., or nearly 2 inches by 1^^ in. {V. Egg Bk. 

 Mus. F. and H.-B,, p. 67 d.). 



The Geog. Range of C. hudsonicus — "All of N. America, and 

 Cuba" (Baird). 



(V. Egg Bk. Mus. F. and H.-B., p. 150, et seq.). 



