524. BRITISH BIRDS. 
chestnut on the breast and belly, though they retain the dark chestnut on 
the flanks and the margins of the under tail-coverts. Newton and Dresser 
treat these two forms as good species, and give the additional characters 
that in the Scandinavian form (Sitta europea) the colours of the upper 
parts are brighter and the legs are lead-coloured, whilst in the southern 
form (Sitta cesia) the colours of the upper parts are duller and the legs 
light brown. It is impossible to agree with this conclusion. The colour of 
the upper parts of Scandinavian and South-European birds is precisely the 
same, though the colour of the upper parts of British examples may be a 
trifle duller than in those from the continent, as is the case with many 
other birds. A difference in the colour of the legs would be a very good 
character; but, unfortunately, it only exists in the imagination of the 
writers above named. All the Nuthatches nearly allied to our bird have 
the same pale brown legs and feet-—a character which distinguishes them 
from the Rock-Nuthatches of the Paleearctic Region and the tropical forms 
of our Nuthatch which inhabit the Oriental Region, both of which have these 
parts lead-colour. The remaining character, the colour of the underparts, 
is equally untrustworthy as a specific distinction, since in Denmark, 
Pomerania, the Baltic provinces of Russia, Poland, and the Crimea, in 
fact wherever the ranges of the two supposed species coalesce, a complete 
series of intermediate forms may be obtained. Further east the variation 
in the colour of the Nuthatches is still continued. In North Russia the 
chestnut on the flanks decreases in extent, the white of the underparts 
becomes purer, and the size (which in the Scandinavian bird had increased 
from the 3°3-8'15 inches of British and South-European examples to 3°5- 
3°35 in length of wing) returns to the dimensions of the Southern form, 
until on the Ural Mountains, extending across Northern Siberia as far as 
Lake Baikal, the amount of chestnut on the flanks has decreased by one 
half, the white on the underparts of adult males has become absolutely 
pure, and the size has diminished until the length of wing only measures 
from 3°2 to 2:9. This form has received the name of Sttta uralensis. 
East of Lake Baikal our information is less complete; but there can be 
little doubt that the changes which take place are equally gradual, and that 
it is only the want of a series of skins from the intervening localities 
which makes the forms appear more specifically distinct. In Kamtschatka 
a form occurs which has been described by Taczanowski as Sitta albifrons. 
It differs in having the head and nape slightly paler in colour, and in 
having the feathers of the forehead at the base of the bill white instead of 
black. The forehead is also white at the base, and the greater wing-coverts 
are tipped with white. Some of my specimens from the Yenesay are 
somewhat intermediate; and an example in Dresser’s collection from 
Hakodate, in the north island of Japan, approaches still nearer the 
Kamtschatka bird. Examples from the Amoor, the island of Askold, and 
