Recently Published Ornithological Works. 213 
northward in November and returning southward in May, 
and I had the pleasute of having some of them stay to dine 
with me. One of their halting places on their way to the 
Orinoco was on islands near the mouth of the Casiquiari, at 
only a few hours’ journey above San Carlos. There I have 
seen them roosting on the tree-tops in such long close lines 
that by moonlight the trees seemed clad with white flowers. 
They descend to the sandy spits of the islands to fish in the 
grey of the evening and morning, i. e. before betaking them¬ 
selves to their eyrie and before resuming their journey on 
the following day. The scarcity of fish in rivers of clear or 
black water is well known ; and even were they more abun¬ 
dant, this very clearness of the water would render it difficult 
for fish-eating fowls to catch them unless when there was 
little light. Hence, perhaps, the Ibis’s choice of hours for 
fishing; and the turbid water poured into the Rio Negro by 
the Casiquiari dulls its transparency at that point, which 
makes it eligible for a fishing station, leaving probably only 
a single day’s stage for the travellers to reach the Orinoco. 
The Ibises, however, did not, as one might have supposed, 
turn up the Casiquiari, but held right on to the north, 
crossing the isthmus of Pimichin, and descending the Ata- 
bapo to the Orinoco. Some of them, I was told, would halt 
on the Guaviare, while others push on to the Apure; the 
former lot, however, are said to travel chiefly by way of the 
Japura from the Amazon. Those that frequent the Upper 
Orinoco return in May, and their halting-place near San 
Carlos is not at the mouth of the Casiquiari, but on the 
islands a day’s journey below the village, so that they are at 
that season less persecuted by the Indians. If they went all 
the way down the Rio Negro in May they would reach the 
Amazon long before its beaches began to be exposed. But 
it has been ascertained that they sojourn awhile on the Rio 
Branco, where the beaches are earlier uncovered. Flocks 
of Wild Ducks sometimes accompany the Ibises, and it is 
quite possible that some of the smaller aquatic and riparial 
Fowls make similar migrations. 
“ When the Ibises are roosting a shot or two from a gun 
