468 BRITISH BIRDS. 
. PARUS CHIRULEUS. 
BLUE TIT. 
(Pate 9.) 
Parus ceeruleus, Briss. Orn. iii. p. 544 (1760) ; Linn. Syst. Nat. 1. p. 841 (1766) ; et 
auctorum plurimorum—TLuatham, Gmelin, Bechstein, Naumann, Temminck, 
Gray, (Bonaparte), Degland, Gerbe, Newton, Dresser, &c. 
Cyanistes ceeruleus (Linn.), Kaup. Natiirl. Syst. p. 99 (1829). 
Parus coerulescens (Linn.), Brehm, Vog, Deutschl. p, 465 (1831). 
The Blue Tit is one of the most widely spread and certainly one of the 
best-known of our native birds. It is found in all suitable districts 
throughout the British Islands, from the Channel Islands in the south to 
the Orkneys and the Shetlands in the extreme north, where, however, it is 
a very rare straggler, but one specimen having been obtained in the first- 
mentioned of the latter two groups of islands. 
The geographical distribution of the Blue Tit is very restricted ; and con- 
sequently the bird does not present any of the differences which we shall 
find in treating of some of the other species of this group. Lach species 
of Blue Tit appears to be subject to very little variation, and to be separated 
from its congeners by a hard and fast line. The Blue ‘Tit is distributed 
over the whole of temperate and Southern Europe, as far east as the Ural 
Mountains and the Caucasus. In Norway, owing to the comparative 
mildness of the climate, it is found as far north as lat. 64°; but in Russia 
it has not yet been obtained further north than lat. 61°. Meves states 
that it is said to have been found at Archangel; but neither Hencke, Piot- 
tuch, Harvie-Brown, nor myself met with it there. Its nearest ally is 
P. persicus, from Persia, which differs in being much paler in colour and in 
having broader white margins to the greater wing-coverts. In Tunis, 
Algeria, and Morocco the Blue Tit is represented by P. ultramarinus, a 
well marked species, differing principally in having the back slate-grey 
instead of yellowish green, and the black on the throat more developed. 
In the Canary Islands P. wltramarinus is replaced by P. tenerife, an island 
form, only differmg from its ally of the mainland by the absence of the 
pale tips to the greater wing-coverts, thé very indistinct tips to the inner- 
most secondaries (which in its ally are broad and conspicuous), and by 
having a slightly longer tail. The next nearest ally of the Blue Tit is 
P. pleskii, from Central Russia, a blue-backed pale form with the portions 
of the underparts that are yellow in the Blue Tit pure white, with the 
exception of a pale yellow spot on the breast. Another European species 
found in Russia and Siberia is the Azure Tit, P. cyanus, somewhat similar. 
to the last mentioned, but still paler blue on the back, with a nearly white 
head, without the black throat and gorget, without the yellow on the 
