354 Observations on the 



their characteristic vivacity. This, indeed, is easily accounted for 

 from their mode of life, for they are obliged, more frequently than 

 others, to perch at the margin of waters or on the outskirts of woods, 

 in order to watch the egress of a frog, a lizard, or an insect, which 

 they immediately seize and devour on the ground. They are there- 

 fore seldom seen hovering after the manner of our " Jean le Blanc,"* 

 or our eagles ; for even the Aguia Eagle and the Buzzards, which 

 hover most, are observed to do so only for a short time in the day, 

 especially in the morning. 



We have noticed among many kinds of American birds of prey 

 a sociable instinct wholly unknown to those of Europe, which, with 

 the exception of vultures, never unite in flocks. The vultures of 

 America are as sociable as those of Europe. They assemble in order 

 to devour dead bodies ; and the caracaras, their faithful imitators, 

 congregate like them on the same carcases, with a like degree of 

 familiarity and confidence ; but in these associations the caracaras 

 are probably more influenced by the desire of obtaining a kind of 

 food common to both, than by any really sociable feelings. The 

 case is different from those assemblies of birds of the same species 

 belonging to other tribes, which move from one place to another in 

 flocks, alight together on the margin of the same lake, perch on the 

 same tree, or even the same bush, in the vicinity of waters and in 

 wooded plains, and rarely separate, at least during their movements 

 over the country ; for we are yet ignorant whether they congregate 

 for an annual migration. However this may be, the birds posses- 

 sing this property are the Cymindis with hooked bills (genus Ros- 

 tramus, Less.) which in this manner continue in company at least for 

 three months in the year, as we assured ourselves by actual obser- 

 vation on the frontier of Paraguay. 



The leaden coloured Buzzard (Falco plumbeus, Lath.) has the 

 same habits. We have seen them in the skirts of woods resting in 

 large flocks on the same dead tree for a whole day together, some of 

 them pursuing birds and others reposing, the latter taking wing 

 when their companions returned to their perch. It is surprising to 

 meet with this social instinct among birds whose mode of life seems 

 calculated to render them jealous, quarrelsome, and solitary : and, 

 indeed, with the exceptions just mentioned, rapacious birds always 

 live alone without experiencing any of that attraction which brings 

 animals into companionship with others of their kind. Even in the 

 season of love, these voracious birds scarcely remain together in pairs 

 for more than two months, when they again separate and take no 

 further notice of each other. It is true that, during this interval, 

 * F. brachydactylus, Wolf. 



