TREE-CREEPER—W REN 23 - 
except the related subspecies, the Scandinavian rock-pipit 
(A. spin. littoralis), which is a rare visitor to Great Britain—by 
the almost complete absence of white on the outer tail- 
feathers. Sexes alike. Upper-parts olive-brown with darker 
striations. Under-parts dull white mostly striated dull brown. 
After the autumn moult the upper-parts have a greenish and 
the under-parts a yellowish hue. 
Nest. Usually in a crevice of a rocky cliff. Material: dry 
grass, bents, lined with finer grass and hair. 
Eggs. Usually 4-5. Greyish to brownish, speckled thickly 
with shades of brown. Av. size, 83x62 in. Laying begins 
April-May. Two broods. 
(6) Family: Certhicde—Tree-creepers 
87. Tree-creeper [Certhia familiaris britannica Ridgway ; 
C. familiaris (Linneeus)]. More or less stationary 
in most woodland districts. 
Bird. Length 55 in. Usually seen creeping up 
and round the trunks of trees. Distin- 
guished by the slender curved beak, long 
pointed tail-feathers, and silky white 
under-parts. The upper-parts are 
mostly brown with paler streaks. 
Rump rust colour. Wings brown 
with buffish bar. 
Nest. Place: usually behind loose 
bark on the trunk of a tree, also be- 
hind ivy stems or in suitable crevices 
in walls, outbuildings, &c. Material: 
twigs, moss, roots, grasses, &c., lined Fig. 21. 
with feathers, wool, down, &c. 
Eggs. Usually 5-6. White, marked generally at the large 
end with reddish spots. Av. size, °61x‘47in. Laying begins 
April-May. 
(7) Family: Troglodytide—Wrens 
38. Wren ([Troglodytes troglodytes troglodytes (Linneeus) ; 
Troglodytes parvulus K. L, Koch]. Resident and common. 
Two other forms, the St. Kilda wren (7. t. hirtensis Dixon) 
and the Shetland wren (7. t. zetlandicus Hartert) are con- 
fined to the islands after which they are named. 
Bird. Length 34 in. The species is easily recognised by 
its small body, short tail, and characteristic shape. (See 
Fig. 22.) The common form has the upper-parts gener- 
