94 BIRDS OF LA PLATA 
Heron would seem a fit @fbject for them, and in the 
course of my rambles I have picked up many in- 
dividuals apparently perishing from inanition. I do 
not wish to insinuate a belief that this immunity from 
vermin is due to the pectinated claw ; for though the 
bird does scratch and clean itself with the claw it 
could never rid the entire plumage from vermin by 
this organ, which is as ill adapted for such a purpose 
as for “‘ giving a firmer hold on its slippery prey.” 
The Spoonbill has also the serration, and is, unlike 
the Heron, an active vigorous bird and usually fat ; 
yet it is much troubled with parasites, and I have 
found birds too weak to fly and literally swarming 
with them, 
I merely wish to call the attention of ornitholo- 
gists to the fact that in the region where I have 
observed Herons they are exempt in a remarkable 
degree from external parasites. 
Much has also been said about certain patches of 
dense, clammy, yellowish down under the loose 
plumage of Herons. These curious appendages may 
be just as useless to the bird as the tuft of hair on 
its breast is to the Turkey-cock ; but there are more 
probabilities the other way, and it may yet be dis- 
covered that they are very necessary to its well-being. 
Perhaps these clammy feathers contain a secretion 
fatal to the vermin by which birds of sedentary 
habits are so much afflicted, and from which Herons 
appear to be so strangely free. They may even be 
the seat of that mysterious phosphorescent light 
which some one has affirmed emanates from the 
