ARDEA COCOI. 



93 



315. ARDEA COCOI, Linn. 

 (COCOI HERON.) 



Ardea cocoi, Burm. La-Plata Reise, ii. p. 508 (Parana, Tucuman, Cordova) ; 

 Scl et Salv. Nomcncl p. 125; Hudson, P. Z. S. 1875, p. 625 (Buenos 

 Ayres) ; Durnford, Ibis, 1877, p. 189 (Buenos Ayres), et 1878, p 309 (Pata- 

 gonia) ; Gibson, Ibis, 1880, p. 158 (Buenos Ayres) ; White, P. Z. S. 1883, 

 p. 41 (Cordova) ; Sorrows, Auk, 1884, p. 271 (Entrerios). 



Description. Above grey ; head above, wings, and tail plumbeous black ; 

 beneath white, neck and sides of belly striped with black : whole length 36-0 

 inches, wing 18'0, tail 7*0. Female similar. 



Hob. North and South America. 



In size, form, and colour the Cocoi closely resembles the Common 

 Heron of Europe; in flight, language, and feeding-habits the two 

 species are identical, albeit inhabiting regions so widely separated. In 

 the southern part of South America it is not seen associating with its 

 fellows, nor does it breed in heronries ; but this may be owing to the 

 circumstance that in the temperate countries it is very thinly distributed, 

 and it is highly probable, I think, that in the hotter regions, where it is 

 more abundant, its habits may not appear so unsocial. Though they 

 are always seen fishing singly, they pair for life, and male and female 

 are never found far apart, but haunt the same stream or marsh all the 

 year round. Azara says that in Paraguay, where it is very scarce, 

 it goes in pairs and breeds on trees. On the pampas it makes its soli- 

 tary nest amongst the rushes, and lays three blue eggs. 



The following general remarks on the Heron apply chiefly to the 

 Ardea cocoi, and to some extent also to other species of the Heron 

 family. 



1 have observed Herons a great deal, and think that there is much 

 to be said in support of Buffon's opinion that they are wretched, indi- 

 gent birds, condemned by the imperfection of their organs to a per- 

 petual struggle with misery and want. 



Much as the different species vary in size, from the Ardea cocoi to 

 the diminutive Variegated Heron of Azara (Ardetta involucris], no 

 bigger than a Snipe, there is yet much sameness in their conformation, 

 language, flight, nesting and other habits. They possess a snake-like 

 head and neck, and a sharp taper beak, with which they transfix their 

 prey as with a dart also the serrate claw, about which so much has 

 been said, and which has been regarded as an instance of pure adapta- 

 tion. A curious circumstance has come under my observation regarding 

 Herons. Birds in poor condition are very much infested with vermin ; 

 whether the vermin are the cause or effect of the poor condition, I do 

 not know ; but such is the fact. Now in this region (the Argentine 



