THE BRITISH NUTHATCH. 223 



emarginated outer webs. Secondaries between 9th and 10th 

 primaries, tips almost square. Tail-feathers rounded and not stiff, 

 tail almost square. Bill strong, wedge-shaped, sloped off to fairly 

 sharp point. A few, fine, short rictal and nasal bristles, and nostrils 

 almost covered with short bristle-like feathers. Claws strong and 

 curved, hind claw decidedly shorter than hind toe. 



Soft parts. Bill dark slate, base of culmen and basal two-thirds 

 of lower mandible grey ; legs and feet yellowish-brown ; iris dark 

 greyish-brown. 



CHARACTERS AND ALLIED FORMS. Sitta e. ccesia (middle Europe) 

 much resembles S. e. britannica but buff of under-parts is usually 

 of a deeper shade, S. e. Jiispaniensis (Spain) is much like britannica 

 but smaller and with shorter bill, 8. e. caucasica (Caucasus) has 

 dark under-parts and short bill, S. e. levantina (Asia Minor, Palestine) 

 has paler under-parts and much finer bill, S. e. persica (Persia) is 

 similar but paler above and below, S. e. europcea (Scandinavia, 

 north Russia) has white under-parts, S. e. homeyeri (east Prussia) 

 has more cream-coloured under-parts, S. e. uralensis (east Siberia) 

 is much like S. e. europcea but smaller, S. e. albifrons (Kamtschatka) 

 has paler upper-parts and white fore-head ; several other forms 

 inhabit China, while others have been named but are doubtful. Blue- 

 grey upper-parts, chestnut flanks, and wedge-shaped bill are 

 unmistakable specific characters. 



FIELD -CHARACTERS. Differs alike in coloration and form from all 

 other British birds. Unlike Tree-Creeper does not use tail in 

 climbing, and moves upwards, downwards and sideways indifferently. 

 Presence often made known by loud tapping as it hacks nuts, and 

 by shells of hazel nuts, acorns, beech-mast and yew seeds wedged 

 into crevices of bark. In flight, which is slow and undulating, 

 short tail, stout head and strong pointed bill very apparent. Call- 

 note a clear loud " twi-twit." In spring this note is repeated by 

 male so rapidly as to produce a bubbling cry. Another spring call 

 is a loud clear whistle. 



BREEDING-HABITS. Usually in a hole in the stem or large branch 

 of a tree at varying heights, occasionally in holes of walls, in Sand- 

 Martins' holes or old Magpies' nests, and twice recorded from the 

 side of a haystack. Nesting-boxes also often occupied. The 

 entrance to the hole is nearly always reduced in size with hard mud. 

 Nest. Hole usually lined with bark of Scotch fir, less frequently 

 birch bark or dried leaves of oak and beech. Eggs. 5-11, usually 

 5-8 ; white, more or less boldly spotted with red-brown and a few 

 violet shell-marks ; occasionally almost unmarked. Average of 

 100 eggs, 19.2 x 14.3 mm. Breeding-season. From the end of 

 April to mid-May, also sometimes late in June. Incubation. Lasts 

 about 13-14 days, probably by hen only. One brood normally, 

 occasionally two. 



