INTRODUCTION. 
77 
sixty-six really indigenous ; and this great relative 
disproportion between the number of truly indige- 
nous birds and the migratory species, occurs from 
so many of the inhabitants of southern Europe 
and the nearest coasts of Asia and Africa reaching 
Great Britain as the extreme of their migration 
northward ; and the opposite course makes the 
great proportion of our winter migratory birds to 
occur among the Grallatores and Natatores, which 
travel southward, making our islands nearly the 
limit of their range in that direction, while they 
occupy the colder latitudes during the summer, 
and perform in these solitudes the process of 
moulting or the cares of incubation. Of the 
Rasores two are now extinct, or very nearly 
so ; three have been introduced ; two are summer 
visitants, and one, the passenger pigeon, has only 
occurred twice, reducing thus our indigenous list 
by nearly a half. 
The progress which British ornithology has 
made has been steady and sure, but it has not 
perhaps been very rapid. It has ever been a 
favourite study with the naturalist, and in Britain, 
previously to 1 800, had a greater portion of care 
bestowed upon it than upon the other branches of 
the vertebrate. For our present purpose of giving 
a very short sketch of its progress, it will not be 
necessary to trace it to a mere distant period than 
1678, the date of the work of Francis Willoughby, 
