16 Mr. E. Gibson oti the Ornithology of [Ibis, 



Dominican Gulls on the samphire-clad mud-flats by lonely 

 Cape San Antonio on the melancholy Atlantic, nor those 

 of the smaller Gulls and Terns, where the wild graceful birds 

 circle and cry over a wide expanse of blue water and green 

 Avater-grasses. Or even where, amidst a wilderness of dark 

 green rushes in the heart of an immense swamp, there 

 are myriads of nests all round ; and the air is filled with 

 thousands of the parent birds, Snowy Egrets, Roseate Spoon- 

 bills, Glossy Ibises, Blue Herons, and Grey Night-Herons. 

 Doubtless the surroundings of the Swan's sanctuary ren- 

 dered it the more impressive : ringed round with great 

 swamps, backed by the limitless Pampas, broken along the 

 horizon by Tala woods or the groups of trees that mark 

 a puesto; no cattle to be seen, nor signs of human life as 

 far as the eye ran reach, only the white buildings of the 

 Yngleses head-station standing boldly out against its woods, 

 a couple of miles away. Given the modern conditions of 

 Argentina, I much fear similar occurrences will soon become 

 a thing of the past, even in our remote district; aud it is 

 well to put them on record. 



In coming to the Ducks proper, I would draw attention to 

 the difficulty attending their full identification and frequency 

 of occurrence, with other observations pertaining thereto. 

 Particularly this is the case with the Teals (five species), 

 aud the two Pintails, the Brown and the Bahama {Dafila 

 spinicauda Vieill. and D. bahamensis Linn.). The trouble 

 arises from the enormous number of the birds in this 

 district, particularly when the swamps are normally or 

 abnormally full of water, and more especially in the spring 

 season when the immigration is at its height. At other 

 times of the year, or if a partial drought has reduced the 

 water-area^ the observer readily identifies and makes a 

 mental note of the recurrent individuals and flocks. But it 

 will easily be understood that on those occasions when 

 countless myriads of birds rise with a roar like thunder on 

 being disturbed, or the air is filled with a flighting snow- 

 storm spread over thousands of acres of marshes, the result 



