the Province of Buenos Ayres. 63 



flimsy and slightly built structure. It contained three eggs 

 of a bright pea-green colour, measuring 1*3 X '9 inch. I 

 flushed one of the old birds from the nest. 



26. Nycticorax obscurus, Bp. ; Ibis, 1877, p. 189. 



In November and December 1876 I found this bird com- 

 mon in large flocks, chiefly immature birds, which do not 

 attain their full plumage till more than a year old. 



27. Phimosus infuscatus (Liclit.) .; Nomencl. p. 127. 

 Last summer I saw some eggs of this bird, obtained, shortly 



before Christmas, about two hundred miles to the south of 

 Buenos Ayres. They are of a bright azure -blue colour and 

 very handsome. A friend who has taken the nests tells me 

 they are found on a dry spot close to a lagoon, and com- 

 posed of a few pieces of grass in a slight hollow. Four is 

 the full complement of eggs. 



15th April 1877. Common in this neighbourhood in large 

 flocks. Birds of the year have much naked skin on the fore- 

 head, and many brown feathers on the head. 



28. Chauna chavaria, Linn. ; Ibis, 1877, p. 190. 

 Though apparently such an awkward unwieldy bird, the 



Screamer can, and frequently does, rise to such a height 

 as to appear a mere speck in the sky, and I have often 

 watched two or three birds gracefully circling round each 

 other like Eagles for half an hour at a time. They are 

 enabled to do this owing to there being a considerable quan- 

 tity of air, which is retained in small cells, between the outer 

 skin and the lining membrane of the body, especially on the 

 chest and stomach, and less visibly on the sides. On the 

 11th February 1877 I shot a young bird in downy state, 

 presumably about ten days old. Head light rust-colour, 

 neck pale grey, back pale chocolate ; wings very small and, 

 with the breast and stomach, grey ; iris wood-brown ; feet 

 brick-red. 



29. Dendrocygna fulva (Gm.) ; Nomencl. p. 129. 

 Common at Alvear in September and at Punta Lara in De- 

 cember, congregating in enormous flocks. Whilst on the 



