SOCIABLE MARSH-HAWK 59 



so that the whole shell is red. The shell is polished 

 and exceedingly fragile, a rare thing in the eggs of a 

 Raptor, 



An approach to the nest is always greeted by the 

 birds with long distressful cries, and this cry is also 

 uttered in the love-season, when the males often 

 fight and pursue each other in the air. The old and 

 young birds usually live together until the follow- 

 ing spring. 



SOCIABLE MARSH-HAWK 



Rostrohamus sociabilis 



Deep slatey grey ; wing feathers black ; rump white ; tail white 

 with a broad grey band ; eyes crimson, bill and feet orange ; length 

 17, wing 13 inches. Female similar but larger. 



THIS Hawk in sise and manner of flight resembles 

 a Bu^ard, but in its habits and the form of its slender 

 and very sharply hooked beak it differs widely from 

 that bird. The name of Sociable Marsh-Hawk, 

 which Azara gave to this species, is very appropriate, 

 for they invariably live in flocks of from twenty to 

 a hundred individuals, and migrate and even breed 

 in company. In Buenos Ayres they appear in Sep- 

 tember and resort to marshes and streams abounding 

 in large water-snails (Ampullarid), on which they 

 feed exclusively. Each bird has a favourite perch 

 or spot of ground to which it carries every snail it 

 captures, and after skilfully extracting the animal 

 with its curiously modified beak, it drops the shell 



