COLUMBINiE. COLUMBA. 
225 
These birds feed on vegetable substances, some chiefly 
on soft fruits, others on nuts, seeds of grasses, and other 
hard fruits, which they swallow entire, some again on the 
herbaceous parts of plants. They walk with ease, and 
even celerity ; have a strong, rapid, and protracted flight ; 
nestle on trees, bushes, rocks, the ground, or in holes, and 
lay two elliptical, pure white eggs. The young, at first 
scantily covered with soft down, are fed with substances 
previously softened in the crop of the parent bird, from 
whose mouth they receive it by introducing their bill. 
FAMILY XXVIII. COLUMBIISriE. COLUM- 
BINE BIBDS, OB PIGEONS. 
There being only the single family of Columbinse in 
the order Gemitrices, the characters of the family and 
order are the same. The variations in the form of the 
wings and tail, as well as other circumstances, give rise 
to a number of generic distinctions. The four species 
which occur in Britain belong to the genus Columba. A 
solitary individual of an American species has also been 
adduced, belonging to the genus Ectopistes, and as others 
have been met with on the Continent, it may be admitted. 
GENUS LXXYI. COLUMBA. DOVE. 
Bill rather short, slender, straight, compressed ; upper 
mandible having at the base two soft, tumid, bare substances, 
placed over the nostrils, the dorsal line straight for half 
its length, arcuato-declinate toward the end, the sides con- 
vex, the tip obtuse and thin-edged ; lower mandible at its 
base wider than the upper, its crura slender and elastic, the 
angle long, the dorsal line short and slightly convex, the 
tip obtuse. Mouth narrow ; tongue sagittate, narrow, taper- 
ing to a point ; oesophagus immediately dilated, and soon 
after expanded into a very large double or two-lobed crop, 
P 
