46 
ON THE CLASSIFICATION OP BIRDS. 
darting with incredible rapidity upon it, before their 
presence has heeii discerned, the alarm note given, and 
a retreat effected. A great deal has been written, and 
now rendered familiar to every one by our cheap com- 
pilations, on the powers of sight in the falconine tribes ; 
but those of the swallows seem to have been quite over- 
looked. It is, nevertheless, difficult to say which is the 
most astounding, the far-sightedness of the former, or 
the instantaneous and complicated discernment of the 
latter. The swallow is proverbially the swiftest flyer in 
the featliered creation; and yet, in the full career of its 
course, it is entirely intent- upon quite another object 
than that of flight. While darting through the air at 
the rate of three miles a minute, it is looking on tlie right 
hand and on the left, sideways, upwards, and down- 
wards, for its food. The insects it preys upon are 
often exceedingly minute — sometimes flying above or 
below the level of the swallow’s flight ; and yet they are 
seen, captured, and swallowed, without any diminution 
of the prodigious rate at which the bird is flying : nay, 
more, any one who attentively watches the swallow skim- 
ming over a meadow in summer, will perceive that it 
will capture two or even three insects in such quick suc- 
cession as to convince us the bird must have had them 
in his eye, to use a colloquial expression, all at once, 
and that the whole are caught and swallowed in as many 
moments. The faculty of vision, in short, in these 
birds, is fully as much developed as in the falcons, al- 
though in a very different way; the one being hug’ and 
the other /luic/c sighted, and both, to a degree, perfectly 
unexampled in the animal creation. Uuffon h.as used 
his eloquence very happily in expatiating on the im- 
mense distance at which the hawk can distinguish his 
prey. He affirms, apparently with truth, that a hawk 
can distinguish a lark, coloured like the clod of earth 
upon which it is sitting, at twenty times the distance at 
which it would be perceived either by a dog or a man • 
but when he asserts that a kite, soaring beyond the reach 
of our sight, can see the lizards and mice on the fields 
