Tits, Wagtails, Flycatchers, Swallows, Etc. 23 



The Common Nuthatch 

 (Sitta ccesia). 



The colouring is very similar 

 in the sexes, but the female is 

 a trifle duller than the male, 

 with the chestnut on the flanks 

 less pronounced. 



The Wrens (Troglodytidce). 



When adult, the hen is rather 

 smaller than the cock; the bill 

 varies enormously with age, 

 and seems to afford no constant 

 character for distinguishing the 

 sexes. 



The Common Wren 

 {Troglodytes parvulus). 



The female is rather duller 

 than the male, and has paler legs, but there does not appear 

 to be any other reliable difference in plumage or colour. 



THE MARSH-TIT. 



THE COAL-TIT. 



HH The Creepers (Certhiidce). 



So far as I could judge by a 

 careful comparison of the large 

 series in the Natural History 

 Museum, the fully adult female 

 is a trifle smaller than the adult 

 male; the bills vary so much 

 with age that it is difficult to 

 form a decided opinion as to 

 whether they present any sexual 

 differences ; I do not think they 

 do. 



The Tree - Creeper 

 (Certhia familiaris). 



The sexes are generally briefly 

 described as "similar," but, from 

 my comparison of numerous ex- 

 amples, I came to the conclusion 

 that the streaking of the upper 

 parts was darker and more 

 regular in female than in male 

 birds. 



