THE FERN-OWL. 
259 
quently met with on heather, or wild places abounding with 
fern, ought more truly to he called Moth-Hawks, from their 
feeding almost entirely 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 provided 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 
i the upper mandible, that as it flies, when in search of food, 
with its mouth open, it has been surmised by some natu- 
ralists 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 annexed figure and p. 241), such a 
prodigious 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 wing, 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 hill, 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 continue to exist; a fact only lately, we believe, 
known, and discovered accidentally by a person who, having 
one evening shot a Goat- sucker, was surprised to see a moth 
come out of its mouth and fly away; and on opening the crop 
the next morning, it was found to contain several other 
moths, which had lived all night in this strange prison, and 
when released ran about the table fluttering their wings, 
s 2 
