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 europcea] the colours of the upper 

 parts are brighter and the legs are lead-coloured, whilst in the southern 

 form (Sitta caesia) 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 Palaearctic 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 3'3-3'15 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 Sitta 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 



