140 HABITS OF BIRDS. 
domestic duties if left to her own efforts; though 
among polygamous birds, as we shall subsequently 
notice, this remark requires to be taken with some 
modification. The instinct, or whatever it may be 
called, which leads birds to ‘anticipate, foresee, and 
provide for this necessity, we cannot, in our pres- 
ent state of knowledge, trace to its immediate 
causes; and we must, therefore, rest contented 
with the knowledge of the observed facts. Some 
of these are not a little interesting, particularly on 
account of the close resemblance of the proceed- 
ings of birds to our own; a resemblance that does 
not hold with those of other classes of animals. 
It might be supposed that birds of prey would be 
in the first instance somewhat afraid of each other 
in their preliminary communications; at least an 
entomologist would readily suppose so, from know- 
ing that it is no uncommon thing among predacious 
insects for the females to make prey of the males, 
even after pairing. Birds of prey, however, though, 
when pressed by hunger, they might not refuse to 
destroy their own species, are not, like spiders, ac- 
tuated by indiscriminate cannibal voracity; and 
though some of the more powerful eagles (Haliztus 
leucocephalus, Savieny, &c.) will pursue their con- 
geners and force them to surrender the prey they 
may have caught, yet we are not aware of any re- 
corded instance of one eagle making prey of an- 
other, as spiders are known to do, and as is com- 
mon among fish. On the contrary, the males and 
females of birds of prey appear to be more closely 
attached than those of most other species. They 
continue together not only during the breeding sea- 
son, but throughout the year, and even for a long 
succession of years, at least if we may trust to the 
circumstantial evidence of a pair of eagles fre- 
quenting the same locality and building on the 
same spot. 
The evidence, indeed, for the birds being always 
