On the European Ccrtliiidaj. 



545 



XXXIF. — A few Remarks on the European Ccrtliiidje. 

 By CoLLiNGwooD Ingram, F.Z.S., M.B.O.U. 



(Text-fig. 2.) 



Thanks to the genei'osity of the Hon. Walter' Rothschihl 

 (who very kindly lent me a number of skins from the Tring 

 JNIuseum to supplement my own specimens), I have recently 

 been able to compare an exceptionally interesting series of 

 Tree-Creepers with those in the British Museum. With 

 this mass of material at my disposal, the separation of the 

 various subspecies becomes a comparatively easy matter. 



Most ornithologists now divide the Tree-Creepers of tlie 

 western Palaearctic Region into two groups, taking Certhla 

 familiaris L. as the type of one and Certhia brachydactyla 

 Brehm for the other. Although the various forms of these 

 birds generally inhabit tolerably well-marked areas, their 

 ranges often coalesce and they are not infrequently found 

 together. This seems to me to be really the only argument 

 in favoTir of giving the two birds specific rank_. for their 

 habits and mode of nidification are practically identical, 

 while their superficial differences apj)ear to be absurdly in- 

 adequate. Among the European Trce-Creepers only the 

 following so-called specific characters appear to be at all 

 constant : — 



C. familiaris. 



Long' hind claw. (Average 

 length mm.) 



Under wing-coverts pure whites 



C. bravhyddctyla. 



Short, arched hind claw. 

 (Average length 7'o mm.) 



lender wing -coverts upiially 

 larked with duslcv. 



Under surface, as a rule, pure 

 white; almost invariably whiter 

 than in C. brachydactyla. 



{Note. — The short bill is a 

 character oi\\j applicable to the 

 northern races, C. f. familiaris, 

 C. f. macrodactyla, and C. f. 

 hritatmica. In these, however, it 

 is very well marked.) 



Under surface usually dirty 

 white; often washed with tawny 

 bull" near the belly. 



