THE RUDDY SHKLD-DUCKS. 263 



I. THE RUDDY SHELD-DUCK. CASARCA CASARCA. 



Afias casarca, Linn. S. N. iii. App. p. 224 (1768). 



Tadonia casarca^ Macg. Br. B. v. p. 19 (1852); Dresser, 



B. Eur. vi. p. 461, pi. 421 (1875) ; 1^- O. U. List Br. B. p. 



122 (1883); Saunders, ed.Yarr. Br. B. iv. p. 347 (1885) ; id. 



Man. p. 409 (1889); Lilford,Col. Fig. Br. B. partxx. (1891). 



Tador?ia rutiia, Secbohm, Br. B. iii. p. 524 (1885). 



Casarca rutiia, Salvad. Cat. B. Brit. Mus. xxvii. p. 177 (1895). 



Adult Male. — General colour above tawny-chestnut ; thawing 

 coverts paler and of a light fawn-colour, with white bases ; 

 bastard-wing, primary-coverts, and quills black ; secondaries 

 black internally, externally bronzy-green with a coppery gloss, 

 the inner secondaries externally deep chestnut, ashy on the 

 inner webs ; lower back pale tawny, vermiculated with dusky- 

 grey ; rump, upper tail-coverts, and tail black, with a greenish 

 gloss ; under surface of body dark tawny, deepening into chest- 

 nut ; under wing-coverts and axillaries white ; the head and 

 neck also tawny, but the crown paler and inclining to white, 

 as also the lores ; round the neck a black collar ; bill black ; 

 feet black, somewhat brownish on the toes and tarsus ; iris 

 black. Total length, 25 inches; culmen, 17; wing, i4"5 ; 

 tail, 4*9 ; tarsus, 2*2. 



Adult Female.— Smaller than the male, and wanting the black 

 collar; the head, face, and wing-coverts whiter ; bill black ; feet 

 brown, blackish on the joints and black on the webs, except 

 at the junction with the toes ; iris deep brown. Total length, 

 2 2 '5 inches; wing, 13-5. 



There seems to be but little difference in colour between 

 the summer and winter plumages of the Ruddy Sheld-Duck, 

 but the feathers have sooty-brown centres in summer, and 

 during the winter the black ring round the neck is absent, 

 while the buff tinge on the wing-coverts is also probably a sign 

 of the breeding-season, as these are white in many birds killed 

 in the winter. 



Young Birds. — Resemble the female, and have no black 

 collar ; they are also more dingy in colour. 



Characters. — Besides the generic features given above, the 

 general tawny-colour of the bird and its size serve to distinguish 

 it from the other Ducks. 



