164 NATURAL HISTORY. 
my secretion. Ifthe insect be of any size it is impaled, 
and if very small, this glutinous substance makes it ad- 
here to the tongue.* 
268. The Cuckoo family is quite an extensive one, con- 
sisting, for the most part, of inhabitants of the warmer 
regions. The species which in spring migrates to Great 
Britain, and is so common there, has the curious habit 
of laying its eggs in the nests of other birds of various 
kinds, making them perform for her the incubation need- 
ed to hatch them. The Cuckoo of this country, though 
very similar in most respects, has no such habit. The 
young European Cuckoos seem to catch the spirit of the 
parent, for they contrive to cast out of the nest the young 
of the bird by which they have been hatched. But, as 
they do this slyly, the foster-mother, knowing nothing of 
it, does not cease her tender care of the intruders. 
269. The fourth order of birds is that of the Rasores, 
or Scratchers. The food of these birds consists chiefly 
of grains and seeds, and they accordingly pass most of 
their time on the ground. They differ in this respect 
from the birds that we have already noticed, which live 
mostly on the wing or on trees. Accordingly, the Ra- 
sores have little power of flight, and the muscles of the 
wings are much smaller in proportion to the size of the 
body than those of the Perchers and other birds of flight. 
Their legs are sufficiently long to enable them to walk 
well, and their feet are armed with short stout nails fitted 
for scratching in search of food. As their food is hard, 
and they have no teeth for masticating it, there is a crop 
for macerating it, and a gizzard for reducing it to pulp. 
* Tt is stated by Mr. Wood that these birds do not injure trees— 
that the insects which they seek for are in decayed branches and 
stumps, and, guided by instinct, the Woodpecker bores only in these. 
This, however, is not so, and I have this summer seen in my garden 
a thrifty pear-tree most curiously marked by the borings of this bird. 
The holes were up the trunk and out upon some of the branches in 
horizontal rows, from five to eight in each row. 
