INTRODUCTION. XXiX 
tion of a nest, — the less necessary, indeed, as the young run or 
take to the water as soon as hatched, and early release them- 
selves from parental dependence. The habits of the other aqua- 
tic birds are not very dissimilar to these; yet it is singular to 
remark that while our common Geese and Ducks, like domestic 
Fowls, have no permanent selective attachment for their mates, 
the Canadian Wild Goose, the Eider Duck, and some others, 
are constantly and faithfully paired through the season; so 
that this neglect of accommodation for the young in the fabri- 
cation of an artificial nest, common to these with the rest of 
their tribe, has less connection with the requisition of mutual 
aid than with the hardy and precocious habits of these unmusi- 
cal, coarse, and retiring birds. It is true that some of them 
show considerable address, if little of art, in providing security 
for their young ; in this way some of the Razor-bills (including 
the Common Puffin) do not trust the exposure of their eggs, 
like the Gulls, who rather rely on the solitude of their retreat, 
than art in its defence; but with considerable labor some of 
the Alcas form a deep burrow for the security of their brood. 
Birds of the same genus differ much in their modes of nidi- 
fication. Thus the Martin makes a nest within a rough-cast 
rampart of mud, and enters by a flat opening in the upper 
edge. The Cliff Swallow of Bonaparte conceals its warm and 
feathered nest in a receptacle of agglutinated mud resembling 
a narrow-necked purse or retort. Another species, in the 
Indian seas, forms a small receptacle for its young entirely 
of interlaced gelatinous fibres, provided by the mouth and 
stomach ; these nests, stuck in clusters against the rocks, are 
collected by the Chinese, and boiled and eaten in soups as 
the rarest delicacy. The Bank Martin, like the Kingfisher, 
burrows deep into the friable banks of rivers to secure a de- 
pository for its scantily feathered nest. The Chimney Swallow, 
originally an inhabitant of hollow trees, builds in empty chim- 
neys a bare nest of agglutinated twigs. The Woodpecker, 
Nuthatch, Titmouse, and our rural Bluebird, secure their 
young in hollow trees; and the first often gouge and dig 
through the solid wood with the success and industry of car- 
