Cape San Antonio, Buenos Ay res. 413 



It is not at all shy, even after being fired at. On one such 

 occasion a female bird approached so close to me that I was 

 able to bring it down with the second barrel^ containing a 

 light charge of No. 10 shot. 



Small birds^ and once a large locust, have been the only 

 results of the examination of three or four crops. 



7. RosTRHAMUs sociABiLis (Vieill.). 



Not uncommon, but very irregular in its appearances. 



Sometimes I have seen a dozen within a week, and after 

 that not met with a single specimen for a year. It is a true 

 marsh-frequenting and marsh-breeding species, and is gre- 

 garious in the nesting-season. In flight it is very slow, beat- 

 ing along over the swamps in a most leisurely manner, and 

 every now and then remainiDg suspended in mid-air, the broad 

 expanded tail working in such a way as enables it to maintain 

 its position almost stationary. A close view (and it is by no 

 means shy) gives one an opportunity of admiring the beauti- 

 ful ruby-coloured eyes, with their darker pupils. No one of 

 our other Raptores is such a lively customer to handle ; and 

 I once came out of a swamp on horseback carrying at arm's 

 length, by the extremities of its wings, a wounded specimen, 

 in a succession of buckjumps that covered me with duck- 

 weed and soaked me to the skin. 



When visiting their breeding colony, I noticed that as the 

 old birds hung suspended over me they produced a creaking 

 sound, similar to that of a door swinging on unoiled hinges, 

 and which was audible at some distance. This cry I do not 

 remember having heard before or since ; and it is, I think, the 

 only one the species gives utterance to. 



Its only food seems to consist of a large water-mollusk, 

 abundant in our swamps, and the empty, but entire, shells of 

 which I have found in the nests. These can only be obtained 

 from the mud at the bottom ; but I have never yet seen the 

 bird fishing for them. Mr. Durnford, in his notes from Ba- 

 radero, in the north of the province, writes " . . . . Food con- 

 sists of water-moUusks ; hence called ' Aguila de Caracoles,' '' 

 but adds nothing as to its method of obtaining them. 



