BRITISH GUIANA (1) 117 
ming-birds and certain species of manakins which are gorgeous. 
The only humming-birds to be met with with any degree of 
certainty at more or less ground level are the Wood-hermits, 
which are somber-plumaged birds with curved bills and long 
graduated tail feathers. These humming-birds are much more 
insectivorous than the rest of the family and spend much of their 
lives scanning the under sides of leaves in the forest undergrowth 
for spiders. Often as I was standing motionless, one of these birds 
would dart to within a few feet of my face to make a close inspec- 
tion. Insects apart, the Hermit Humming-bird to my mind exhibits 
the finest example of motion-control in space of anything in the 
animal kingdom. It will approach one at full speed, stop and 
hover a few feet before one’s eyes, then move vertically up and 
down the length of one’s body as if to satisfy its curiosity (though 
perhaps to see if any spiders are clinging to one’s person) ; then it 
will let in the clutch and disappear like a flash behind one’s back 
to continue its inspection. A sudden flick of the arm will cause it 
to move like lightning, but not to panic. Usually it will just shoot 
through the air a few yards, hover awhile, and then make off in 
its own time. It can go through thick undergrowth at great speed 
and, like the rest of the family, can reverse as well as remain sta- 
tionary or move vertically up and down. 
To revert to the Wood-hermit Humming-birds. I remember a 
forestry officer telling me about an extraordinary communal 
gathering of a species called the Cayenne Wood-hermit. He found 
a number of these birds congregated together in a space of an acre 
or so in the heart of the forest. There was nothing to attract them 
in the way of food, but there they remained spread out evenly, 
sitting in the trees uttering their cricket-like call-notes and occa- 
sionally hunting for food, day after day and week after week. This 
is contrary to the general behavior of any humming-bird, and 
wood-hermits are normally seen only singly or in pairs. 
I saw nothing of this curious happening but it remained in my 
mind, and if I may be allowed to jump ahead to my next expedi- 
tion to British Guiana some seventeen years later, I can give an 
eye-witness account of this strange behavior exactly as it had 
been described to me. 
On this second expedition I was staying inland along the Potaro 
