THE FERN-OWL. 
63 
upon these soft-winged insects, which they catch up 
in their flight, however dark it may he. To human 
beings, who at dusk can scarcely trace a swift-flying 
moth as it glances by, it is inconceivable how this 
bird can contrive to make its constant meals on such 
precarious prey. Nature, however, has amply pro- 
vided it with never-failing means of feasting to its 
satisfaction. In the first place, the eye is large, full, 
and clear, like the Owl's, and so thin and transparent 
is the membrane separating it from the base of the 
upper mandible, that as it flies, when in search of 
food, with its mouth open, it has been surmised by 
some naturalists, that the bird is enabled thereby to 
keep a look out forward, as well as on either side, 
through the thin bony membrane. At all events, 
without this odd addition to great powers of vision, 
a skull more than half filled up with eye-sight, must 
enable the possessor to see more clearly in the dark 
than we can conceive possible. But in the next place, 
look at the mouth (see figure, p. 62 and 39), such a pro- 
digious opening as it is, with a fringe of strong 
bristles on either side of the nostrils, the use of 
which is this : — that as it flies along, if a moth crosses 
the pathway of these widely-opened jaws, the bristles 
fetter the insect's wings, and help to imprison it 
beyond the power of escape. 
This bird has moreover another peculiarity, adapted 
for the capture of moths, namely, a kind of glutinous 
liquid, which exudes from the upper part of the bill, 
and is so adhesive that small insects are retained by 
it, and it is thus enabled to imprison and swallow a 
number of them together ; and what is still more 
singular, that, although swallowed, they still con- 
