449 CERTHIID#. 
black tipped with ashy, which gradually changes to white and 
increases in extent towards the outer tail-feathers ; chin and 
throat pure white; remainder of lower plumage ashy slate, the 
under tail-coverts fringed with white ; axillaries crimson. 
Colours of soft parts. Iris dark brown ; bill, legs and feet black- 
Measurements. Total length about 170 to 180 mm.; wing 94 
to 102 mm.; tail about 50 to 54 mm.; tarsus 25 to 27 mm.; 
culmen 27 to 82 mm. 
In summer the crown of the head becomes grey and the chin 
and throat black. The female has generally rather less black on 
the throat than the male. 
The young resemble the adult in winter plumage but there is 
less crimson on the wing and all the quills have each two rufous 
spots on the inner web. These spots gradually disappear, except 
on the first four large primaries, where they eventually turn white. 
Distribution. The mountains of Europe and Asia, breeding 
throughout the Himalayas at suitable elevations and descending 
lower in winter, occasionally venturing actually into the plains in 
exceptionally cold weather. 
Nidification. The Wall-Creeper breeds throughout the Hima- 
layas between 14,000 and 16,000 feet, in some cases as low as 
12,000 feet. Whitehead found it breeding in Chitral and the 
Kurram Valley and Whymper actually found its nest with young in 
June in the Lidar Valley in Garhwal. The young were old enough 
to leave the nest on the 27th of that month. In Tibet it breeds in 
some numbers just above the Gyantse Plains at little over 12,000 feet, 
laying in the early part of May onwards. Owing to the inacces- 
sible places in which it builds and to its habit of placing its nest 
deep down in crevices of unbreakable rock, few nests have been 
taken in India, though the Tibetans know well many places in 
which it breeds. The nest is just a pad of moss and grass, more 
or less mixed and lined with wool, fur or hair, wedged 
into the bottom of some deep but narrow crevice of the rock-face 
of a precipitous cliff. The eggs number four to six and are 
pure, but rather dull, white with a few specks and spots of black 
or deep red-brown at the larger end. In shape they are broad 
ovals, decidedly compressed and pointed at the smaller end. The 
measurements of 26 eggs, including 15 mentioned by Hartert, 
are:—average 21°3x 14-9 mm.; maxima 22°7x15°7 and 20°8 x 
16:0 mm., minima 20:0 x 14:0 mm. 
Habits. This beautiful little bird haunts the face of precipitous 
cliffs aud great rocks, scuttling about over their surface just as the 
Tree-Creepers do over the trunks of great trees. Unlike the 
Tree-Creepers, however, they have a habit of constantly fluttering 
about the holes and crevices as they search for their insect food 
and, when so employed, they are singularly like large and beautiful 
butterflies. This curious habit has earned them the name of 
