GEOGRAPHICAL DISTRIBUTION 339 
as no indication of loss of wing-power, which is one of the effects of 
protracted isolation, has been observed among them, though, as is 
well known, many of the Insects are said to shew it remarkably. 
Moreover, the colonization seems to be going on still, and it happens 
not unfrequently that when an island has a well-established local 
race it is yet more or less regularly visited by individuals of the 
normal and parental form. 
The European Province does not seem to possess a single genus 
that can be accounted peculiar to it, but it has one consisting of a 
single species, Mergulus alle (ROTCHE), which does not elsewhere 
occur in the Palearctic Subregion, though it inhabits the northern 
parts of the Canadian Province of the Nearctic. It would, how- 
ever, extend too far for the present article to dwell upon more 
than a very few of the curiosities of distribution revealed by the 
continued observation of birds in Europe. There is no need to 
travel out of our own island to meet with some of the most 
remarkable among them, and we may take the case of the NiGut- 
INGALE as an example. In England the western limit of this 
incomparable songster’s range seems to be formed by the valley of 
the Exe, which is only overstepped on rare occasions. But even 
in the east of Devon it is local and rare, as it also is in the north 
of Somerset, though plentiful in other parts of that county. Cross- 
ing the Bristol Channel, it is said to be not uncommon at times 
near Cowbridge in Glamorganshire ; but this seems to be an isolated 
spot, or at any rate there is no evidence of its being found else- 
where in Wales, or between that place and Tintern on the Wye, 
where it has been reported to be plentiful. Thence there is more 
or less good testimony of its occurrence in Herefordshire, Shrop- 
shire, Staffordshire, Derbyshire, and so on, to about 5 miles 
north of York, but not further, that is to say in the ordinary 
course of things, for Mr. Wolley-Dod, an unquestionable authority, 
recorded one that he heard singing at Malpas in Cheshire in May 
1889.1 Along the line thus sketched out, and immediately to the 
south and east of it, the appearance of the Nightingale, even if 
regular, which may be doubted, is rare, and the bird is very local ; 
but in many parts of the midland, eastern, and southern counties 
it is abundant, and the woods, coppices, and gardens ring with that 
thrilling song which has been the theme of writers in all ages. 
There are many assertions of its occurrence in England further to 
the northward, but some of them rest on anonymous authority 
only, and all must be regarded with the greatest suspicion. Still 
more open to doubt are the statements which have been made as 
to its visits to Scotland, while in Ireland there is no pretence even 
of its appearance. No reasonable mode of accounting for the 
1 Others were reported to have been heard about the same time in Flintshire 
and near Rhyl. ; 
