500 A PRACTICAL HANDBOOK OF BRITISH BIRDS. 



Measurements and structure. <$ wing 87-95 mm., tail 48-55, 

 tarsus 28-31, bill from skull 21-23 (12 measured). $ wing 84-92 

 (one 80). Primaries : 1st equal to, or 1-4 longer than, primary- 

 coverts, 2nd, 3rd and 4th longeet and often equal but 2nd or 4th 

 usually 1-2 mm. shorter than 3rd, 5th 2-5 shorter, 6th 7-10 shorter ; 

 3rd to 5th emarginated outer webs. Secondaries rather shorter 

 than 10th primary, tips rounded. Tail square but outermost pair 

 slightly shorter than rest, 12 feathers, tips fairly square. Upper 

 and under tail-coverts about three-fourths as long as tail. Bill 

 strong and compressed. Nostrils slit -like being covered by mem- 

 brane. No rictal or nasal bristles. Legs, feet and claws strong 

 and last somewhat curved. 



Soft parts. Bill brown -black, tinged slate at base of lower 

 mandible ; legs and feet black-brown, front of tarsus and toes 

 whitish-slate ; iris brown. 



CHARACTERS AND ALLIED FORMS. C. c. aquaticus (France, Germany) 

 is like C. c. britannicus on belly but has paler more slate-grey 

 upper -parts ; C. c. pyrenaicus (Pyrenees) has upper -parts like C. c. 

 aquaticus but belly like C. c. cinclus ; C. c. meridionalis (Alps, 

 Balkans) is very near C. c. aquaticus, but crown is rather paler and 

 belly brighter rufous ; C. c. sapsworthi (Corsica, Sardinia) is much 

 like C. c. pyrenaicus but crown and nape are paler brown ; C. c. 

 minor (Atlas Mts.) has longer bill, pale upper -parts and pale chestnut 

 on belly ; C. c. caucasicus (Caucasus, Asia Minor, north Persia) has 

 chocolate-brown instead of chestnut -brown on lower-breast and 

 belly ; C. c. cashmiriensis is similar but darker brown on belly and 

 this extends farther over flanks and brown of nape extends on to 

 mantle ; C. c. rufiventris (Lebanon) like C. c. caucasicus but more 

 rufous on belly ; C. c. persicus (south-west Persia) paler rust-brown 

 belly and pale upper -parts, juvenile with very narrow dark tips 

 to the feathers ; C. c. leucogaster (west Siberia, Turkestan, Baikal) 

 white extends over belly and chocolate-brown over mantle. The 

 short tail, white " bib " in adult, and white under -parts and slate 

 upper-parts, mottled with black-brown in juvenile, are distinctive 

 specific characters. 



FIELD -CHARACTERS. In form and behaviour unlike any other 

 native species. Identified at once by rotund form, pure white 

 throat and breast, dark upper -parts, and chestnut band on belly. 

 Frequents rivers, mountain torrents and tarns. Habit of curtsying 

 on boulder, often in mid -stream, characteristic. Food obtained 

 by wading, swimming and diving. Strong and rapid flight, per- 

 formed by continuous beats of short wings, usually follows course 

 of stream. Song a sprightly warble, often uttered in flight, bears 

 some resemblance to Wren's. Call -note a sharp " chit, chit." 



BREEDING -HABITS. Haunts rapidly flowing streams, and nests on 

 face of cliffs by waterside, in holes of walls, under bridges, in ivy 



