PRATINCOLES. 
47 i 
immature birds assume the bright summer plumage of the adults, although thej^ 
differ from the latter in having brighter wing-coverts; these feathers being only 
changed by the adults in the autumn, and thus permanently presenting the dull 
hues of the winter dress. In their habits all the members of the order are more 
or less migratory, and from this cause the winter distribution of the group is well- 
nigh cosmopolitan. Considerable diversity of view obtains as to the classification 
of the typical Limicolse. By some they are divided into the three family 
groups of plovers, sandpipers and snipes, and pratincoles; the thicknees—here 
classed with the bustards—being added as a fourth. In his monograph on the 
distribution of these birds, Mr. Seebohm classed the whole of them (inclusive of 
the thicknees) in a single family, but in a later work he removed the thicknees 
and the black-backed courser to form one family, and the coursers and pratincoles, 
together with certain other birds, as a second family; both of which were placed 
next to the gulls. An equally marked diversity of view obtains as to the number 
of genera into which these birds should be divided; Mr. Seebohm being one of 
those who uses such terms in an extended sense. In both these matters we 
endeavour to take a middle course. 
Pratincoles and Coursers. 
Family CUBSORIIDAE. 
The birds above-named differ from all the other members of the order in the 
want of basipterygoid processes on the rostrum of the under surface of the skull; 
while they are further characterised by having their oval nostrils opening on the 
surface of the beak without being sunk in a groove. In both these characters 
they resemble the thicknees, to which the black-backed courser presents a further 
approximation in the oval (holorhinal) nasal apertures of the skull. Externally, 
these birds may be distinguished from the thicknees and bustards by the presence 
of four toes in the pratincoles and by the metatarsus of the coursers being covered 
with scutes instead of reticulated scales. The absence of basipterygoid processes 
in these birds cannot justify their affiliation to the gulls; but it may be a question 
whether the pratincoles are rightly included in the same family as the coursers. 
The forked tail and somewhat swallow-like appearance and 
habits of the pratincole (Glareola pratincola) render it, at first sight, 
somewhat difficult to believe that these birds are near relatives of the plovers; but 
closer observation will show that their comparatively long legs are adapted for 
running in the usual plover-like manner, and that it is only when on the wing 
hawking for flies that a superficial resemblance is presented to the swallows. 
Moreover, in certain members of the genus, the forking of the tail is well-nigh 
obsolete. As a group, these birds, of which there are ten species, are characterised 
by the presence of the first toe, and by the tail being more or less forked. The 
third toe is united to the fourth by a short membrane; and the first quill of the 
wings is the longest. By Mr. Seebohm they are regarded as specially modified 
allies of the coursers, retaining the first toe of the ancestral stock. Many of them 
show resemblances to the latter in their black under wing-coverts, white upper 
Pratincoles. 
