THE AMERICAN WATER-PIPIT. 187 



deep buff or pale buff, never white as in A. s. spinoletta or olivaceous 

 as in A. s. petrosns ; streaks of breast and flanks narrower and 

 blacker, not so brown as in A. s. spinoletta and not so olivaceous 

 as in ^. s. petrosus ; axillaries whitish as in ^. s. spinoletta ; wings 

 and tail Hke A. s. spinoletta with light portions of outer tail- 

 feathers white. This plumage is acquired by complete moult 

 in July-Sept. Summer. — The body-plumage, lesser and median 

 wing-coverts, and usually imier gi-eater coverts, some innermost 

 secondaries and central tail-feathers are moulted Feb. -April, but not 

 rest of wings and tail ; upper-parts become brown tinged grey, 

 the edges of the feathers of crown and mantle being somewhat 

 ashy-grey, much as in A. s. littoralis, but usually with a more 

 ashy tinge ; paler, more grey and less warm brown, on mantle 

 than ^4. s. spinoletta ; eye-stripe and under-parts varying from 

 buffish-pink scarcely streaked to pinkish-buff with almost as many 

 streaks as in winter ; belly and under tail-coverts more buff, not 

 so white as in A. s. spinoletta. N.B. — Much worn specimens 

 have very httle buff tinge on under-parts. 



Nestling and Juvenile. — (Not exammed.) 



First winter and summer. — ^Like adults. 



Measurements and structure. — (^ wing 82-89 mm., tail 62-69, 

 tarsus 22-23, bill from skull 12-14 (12 measured). $ wing 78-82. 

 Structure as in A. s. petrosus. 



Breeding-habits. — Breeds in depression of ground, or in cavity 

 sheltered by rocks, sometimes deep down in crevice. Nest. — 

 Loosely built of dead grasses. Eggs. — Usually 4 or 5 ; resembling 

 those of Rock-Pipit, varying considerably and ranging from 

 pinkish to greenish or brownish in general tone, but all closely 

 freckled with fine spots. Average of 44 eggs, 19.5 x 14.58 mm. 

 Breeding-seasdn. — Second half of June. Incubation. — Period un- 

 known : probably by hen. 



Food, — Insects, small seeds, small mollusca and Crustacea. 



Distribution. — Scotland. — Young male St. Kilda (0. Hebrides), 

 Sept. 30th, 1910 (W. Eagle Clarke, Ann. S.N.H., 1911, p. 52 and 

 Studies in Bird Migration, ii, p. 212; cf. Brit. B., iv, p. 285). 

 The specimen mentioned by Edwards {ut supra), and those 

 recorded by MacGillivray {Man. Brit. Birds, p. 169), were 

 probably A. s. littoralis {cf. Yarrell, i, p. 590). 



Distribution. — Abroad. — Breeds in Arctic zone from north-east 

 Siberia, north Alaska, north Mackenzie ^ on both sides of Davis 

 Strait south to Great Slave Lake, north Quebec and Newfoundland, 

 and from Aleutian Islands and Prince William Sound, as well as 

 on high mountains south to California and mid-Mexico. Winters 

 from south United States to Guatemala, also on Bermuda. Has 

 occurred twice on Heligoland. 



