102 HeErRRIcK, Care of Nest and Young. hea 
Cleanliness is an imperative instinct with such birds as the 
Kingfishers and Bank Swallows, whose nests are placed in the 
ground, while Barn and Eave Swallows, House Sparrows, and 
Pigeons represent a considerable number of other species 
which secure protection by placing their nests in remote, high, 
or inaccessible places. While their nests may be clean, the 
ground beneath them usually is not. 
It is plainly advantageous for birds which breed on or near 
the ground to remove every particle of litter which would stain or 
whiten the leaves and surrounding foliage, and thus advertise the 
secret of their nest to enemies, even to those who prowl after 
dusk. When a Red-eyed Vireo, whose behavior I studied at 
close range, dropped any bit of excrement by accident, she darted 
after it with such speed that it was snatched up before reaching 
the ground, or before falling a distance of four feet. Not a trace 
of defilement is ever seen around the dwellings of any of these 
birds. 
On the other hand, predaceous species like Hawks pay no 
attention to such matters. The excrement of their young is 
voided in a semi-fluid state and in a peculiar manner. With tail 
turned to the edge of the nest the bird shoots it off to a distance 
of two or three feet, and it may strike the ground six or seven 
feet from the nesting tree. The only significance which such 
actions have is that of keeping the nest clean. The advertise- 
ment of the nest stains on the leaves below is a matter of indif- 
ference to these bold and persistent outlaws, who have little to 
fear from any enemy save men. 
Owls, who breed in holes in trees, are reported to have filthy 
nests, especially where the cavity has been in use for several 
successive years, but this seems to be due to the remains of their 
quarry and to the accumulation of rejected food-pellets rather 
than to the presence of excrement. 
The haunts of certain sea fowl are often reeking with filth 
during the breeding season, and the guano beds of the South 
American coast mark the places of assembly and probably of the 
breeding of myriads of sea fowl for long periods of time. How- 
ever, the birds themselves and their nests are generally clean, and 
any other condition in the case of most birds would soon become 
intolerable. 
