XIV 
PREFACE. 
selves to all the changes of this variable climate. They are the 
only species which strictly merit the epithet Indigenous. 
The Periodical Visitants chiefly belong to the class of Birds 
Some of these come from more southern latitudes, to spend the 
summer, and bring forth their young ; while others arrive from 
more northern latitudes, to escape the rigours of an arctic win- 
ter. The vernal shifting the author has denominated Equato- 
rial Migration^ the autumnal shifting the Polar Migration. 
All the species of these groups, though intimately connected with 
the country, by the regularity of their visits, enjoy a right of 
citizenship less perfect than the resident animals. 
Stragglers., or irregular visitants, have hitherto occupied a 
higher rank in every British Fauna, than they seem entitled to 
possess. Driven from their native haunts to this country by 
some temporary calamity, the persecution of foes, or the fury of 
a storm, they have been recorded inconsiderately as indigenous 
species. Their occurrence, as serving to illustrate the distribu- 
tion of species, should be recorded, but not in such a manner as 
to assimilate them with the resident kinds, and periodical visi- 
tants. Acting upon this principle, the author has been com- 
pelled to degrade to the rank of Stragglers, several Birds and 
Fishes which have long occupied a more distinguished place. 
The Extirpated Animals are such species as still maintain 
their ground in other regions, but have been destroyed in this 
country by the long continued persecutions of man. 
The Extinct Animals are such as once dwelt in this country, 
but which have disappeared, and, from various causes, seem to 
have perished from off the earth. 
The remains of the extirpated animals, or such as history 
records to have lived in the country, are occasionally found im- 
bedded in several of the superficial or modern strata, in com- 
pany with the relics belonging to the yet indigenous species. 
Along with both of these, also occur the relics of several species, 
concerning which the voice of tradition is silent. Interred, how- 
ever, in the same grave with the relics of individuals belonging 
to existing species, and such as have perished by human agency, 
and belonging to tribes which at all times have been the objects 
of the huntsmaif s pursuit ; the author has referred their de- 
^itmction to the ■influence of the cJiase^ and has exhibited his views 
