526 Mr. E. Gibson on the Ornithology of [Ibis, 



do not afford it the requisite rush-coverts). I judge it to be 

 partly migratory, as it is scarcer in the winter-time. 



In my round journey between Buenos Ayres and Ajo, 

 15-25 September of 1913., at the height of the inundation. 

 I did not observe a single individual, nor on the Yngleses in 

 the interval. The first was noted there on 10 October, after 

 which it continued to be observed — sparsely — until the end 

 of December. In January 1914 there were more individuals 

 and some small flocks which, by the 30th of that montii, had 

 so increased, that I wrote: " In great numbers, amounting 

 to considerable flocks in some cases. I have certainly never 

 seen so many in one day." February was similarly prolific : 

 but, as I remarked, " The summer heats have produced such 

 dense surface-growth of duck-weed, that this and other 

 similar species are forced to congregate at the so-called 

 passes, where traffic has left some open water.^' The 

 following year (1915), during the months of September and 

 October, I found it generally distributed, though not so 

 abundant as in the previous season. 



Hudson has mentioned its habit of constructing false 

 nests or platforms to perch upon, formed by breaking down 

 the rushes across each other. These, in my early days, were 

 a source of mystery to me, as I looked, upon them as embryo 

 nests for breeding-purposes. The perch selected for a fishing- 

 station is generally a stout duiasuillo beside clear water, 

 the bird's weight being sufficient to bend down the sapling 

 to the desired height. 



To quote from Hudson, " On being disturbed by day it 

 rises heavily flapping with a loud qua-qua cry." At night- 

 time, the note produced is a strong fox-like bark (very eerie 

 as the horseman struggles through the deep and apparently 

 endless swamps), and I have heard them repeating the same 

 note as they circled restlessly round the head-station 

 buildings at night after a heavy rain. 



In ' The Ibis " for 1880, p. 156, 1 described a nesting-colony 

 of the year 1873, where it was in community with both 

 Egrets {A. eyretta and A. candidissima). One such other 

 1 discovered in 1884. Tliis time, alas, its only confrere 



