NYCTICORAX OBSCURUS. 



105 



Hab. Paraguay and N. Argentina. 



Graf v. Berlepsch has recently shown that the Tiger-Bittern of Para- 

 guay differs from Tigrisoma brasiliense (which it generally resembles in 

 plumage) in having the base of the lower mandible partly feathered as 

 in T. fasciatum. It is probable that the Argentine Tiger-Bittern 

 belongs to the same form, but we have not yet met with adult specimens 

 of it. It occurs in the northern provinces of the Republic, and was 

 obtained by White in Corrientes, and by Durnford in Salta. 



323. NYCTICORAX OBSCURUS, Bp. 

 (DARK NIGHT-HERON.) 



Nycticorax obscurus, Scl. et Salv. Nomencl. p. 126; Durnford, Ibis, 1878, 

 p. 63 (Buenos Ayres), et p. 399 (Patagonia); Gibson, Ibis, 1880, p. 158 

 (Buenos Ayres). Ardea garden!, Burm. La-Plata Reise, ii. p. 508 

 (Parana). Nycticorax garden!, White, P. Z. S. 1882, p. 624 (Buenos 

 Ayres and Salta) ; Barrows, Auk, 1884, p. 271 (Entrerios). 



Description. Above cinereous; front white; head, nape, and scapulars 

 greenish black ; elongated nuchal plumes white : beneath paler, whitish on 

 throat and middle of belly ; bill black ; feet flesh-colour : whole length 26-0 

 inches, wing 12'0, tail 4-8, tarsus 3'2. Female similar. 



Hab. Southern half of South America. 



In the Argentine Republic the Night-Heron lives in communities, 

 and passes the hours of daylight perched inactive on large trees or in 

 marshes on the rushes, and when disturbed by day they rise up with 

 heavy flappings and a loud qua-quo, cry. At sunset they quit their 

 retreat, to ascend a stream or seek some distant feeding-ground, and 

 travel with a slow flight, bird succeeding bird at long intervals, and 

 uttering their far-sounding, hoarse, barking night-cry. 



Where the flock lives amongst the rushes, in places where there are 

 no trees, the birds, by breaking down the rushes across each other, 

 construct false nests or platforms to perch on. These platforms are 

 placed close together, usually where the rushes are thickest, and serve 

 the birds for an entire winter. 



The breeding-habits of the Night-Heron have already been described 

 in the account of the Ardea egretta. 



In the Falkland Islands, where Captain Abbott discovered a heronry 

 (cf. Ibis, 1861, p. 157), their breeding-habits are the same as on the 

 pampas. 



