320 
ISLAND LIFE. 
[part II. 
Plants, which have considerable facilities for passing over the 
sea, are somewhat intermediate in proportionate numbers, there 
being about 970 flowering plants and ferns in Ireland to 1425 in 
Great Britain, — or almost exactly two-thirds, a proportion inter- 
mediate between that presented by the birds and the mammalia. 
Peculiar British Birds. — Among our native mammalia, reptiles, 
and amphibia, it is the opinion of the best authorities that we 
possess neither a distinct species nor distinguishable variety. In 
birds, however, the case is different, since some of our species, 
in particular our coal-tit ( Parus ater) and long-tailed tit ( Parus 
caudatus) present well-marked differences of colour as compared 
with continental specimens ; and in Mr. Dresser’s work on the 
Birds of Europe they are considered to be distinct species, while 
Professor Newton, in his new edition of Yarrell’s British Birds, 
does not consider the difference to be sufficiently great or suffi- 
ciently constant to warrant this, and therefore classes them as 
insular races of the continental species. We have, however, 
one undoubted case of a bird peculiar to the British Isles, in the 
red grouse ( Lagopus scoticus), which abounds in Scotland, Ireland, 
the North of England, and Wales, and is very distinct from any 
continental species, although closely allied to the willow grouse 
of Scandinavia. This latter species resembles it considerably in 
its summer plumage, but becomes pure white in winter ; whereas 
our species retains its dark plumage throughout the year, be- 
coming even darker in winter than in summer. We have here 
therefore a most interesting example of an insular form in our 
own country ; but it is difficult to determine how it originated. 
On the one hand, it may be an old continental species which 
during the glacial epoch found a refuge here when driven from 
its native haunts by the advancing ice ; or, on the other hand, it 
may be a descendant of the Northern willow grouse, which has 
lost its power of turning white in winter owing to its long re- 
sidence in the lowlands of an island where there is little permanent 
snow, and where assimilation in colour to the heather amonsj; 
which it lurks is at all times its best protection. In either case 
it is equally interesting, as the one large and handsome bird 
which is peculiar to our islands notwithstanding their recent 
separation from the continent. 
