INTRODUCTION. 
17 
{Troglodytes *brevirostris), and, with ready address, constructs its 
globular nest wholly of the intertwined sedge-grass of the tussuck 
on which it is built ; these two species never leave their subaquatic 
retreats but for the purpose of distant migration, and avoid and 
deprecate in angry twitterings every sort of society but their own. 
Among the most extraordinary habitations of birds, illustrative of 
their instinctive invention, may be mentioned that of the Bengal 
Grosbeak , whose pensile nest, suspended from the lofty boughs of 
the Indian fig-tree, is fabricated of grass, like cloth, in the form of a 
large bottle, with the entrance downwards; it consists also of two 
or three chambers, supposed to be occasionally illuminated by the 
fire-flies, which, however, only constitute a part of the food it proba- 
bly conveys for the support of its young. But the most extraordi- 
nary instinct of this kind known, is exhibited by the Sociable or 
Republican Grosbeak ( Ploceus socius, Cuvier) of the Cape of Good 
Hope. In one tree, according to Mr. Paterson, there could not be 
fewer than from 800 to 1000 of these nests, covered by one general 
roof, resembling that of a thatched house, and projecting over the 
entrance of the nest. Their common industry almost resembles 
that of bees. Beneath this roof there are many entrances, each of 
which forms, as it were, a regular street, with nests on either side, 
about two inches distant from each other. The material which they 
employ in this building, is a kind of fine grass, whose seed, also, at 
the same time, serves them for food. 
That birds, besides their predilection for the resorts of men, are 
also capable of appreciating consequences to themselves and young, 
scarcely admits the shadow of a doubt : they are capable of commu- 
nicating their fears, and nicely calculating the probability of danger, 
or the immunities of favor. We talk of the cunning of the Fox, and 
the watchfulness of the Weasel ; but theEagle, Hawk, Raven, Crow, 
Pye, and Blackbird, possess those traits of shrewdness and caution, 
which would seem to arise from reflection and prudence. They 
well know the powerful weapons and wiles of civilized man. With- 
out being able to smell powder , a vulgar idea, the Crow and Black- 
bird at once suspect the character of the fatal gun ; they will alight 
on the backs of cattle without any show of apprehension, and the 
Pye even hops upon them with insulting and garrulous playfulness ; 
but he flies instantly from his human enemy, and seems, by his 
deprecating airs, aware of the proscription that affects his existence. 
A man on horseback, or in a carriage, is much less an object of sus- 
picion to those wily birds, than when alone ; and I have been fre- 
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