THE RED-THROATED DIVER. 475 



Nestling. — Like that of Black-throated Diver. 



Juvenile. — Like winter adult but crown and back of neck more 

 uniform ash-grey with narrow inconspicuous black-brown streaks ; 

 rest of upper -parts much browner, not so black as adult winter and 

 spots more greyish, not so pure white, and smaller, being narrower 

 and longer and forming narrow triangular edges to feathers, this 

 being especially noticeable on scapulars and wing-coverts ; under - 

 parts white but cheeks, sides of neck and throat thickly speckled 

 brown ; flanks browner than in adult and feathers edged white, 

 not spotted ; vent mottled brown ; under tail-coverts white 

 with very narrow brown margins, lower ones brown with narrow 

 white tips ; tail-feathers brown narrowly tipped greyish, becoming 

 whitish when worn ; primaries and secondaries as adult but all 

 latter narrowly tipped white. 



First winter. — The juvenile plumage is only partially moulted 

 as in C. immer but apparently later (Feb.-Mar.). Summer. — A 

 certain amount of moult takes place and some summer plumage is 

 acquired. Insufficient material is available to decide extent of this 

 moult but April examples have a mixture of juvenile and first 

 winter body-feathers and tail-feathers with some red feathers 

 growing on throat and some grey on sides of head, all wing-feathers 

 old and very worn. 



Measurements and structure. — £ wing 276-310 mm., tail 42-55, 

 tarsus 67-78, bill from nostril 38-46 (12 measured). ? wing 257- 

 308, bill 33-44. Primaries : 1st very small and hidden by primary- 

 coverts, 2nd longest, 3rd as long or sometimes 1-3 mm. shorter, 

 4th 7-12 shorter, 5th 25-38 shorter, 6th 40-50 shorter. Rest of 

 structure as C. immer. 



Soft parts. — Bill pale grey with dark stripe along top of culmen 

 (juv. rather paler) ; legs and feet outside and outer toe nearly 

 black, rest pale grey, mottled dark grey at joints of toes, webs flesh- 

 coloured in centre with dark grey margins ; iris (ad.) wine -red, 

 (juv.) red-brown. 



Characters. — No subspecies. Spotted upper -parts in winter and 

 juvenile and red throat in summer distinguish it from other 

 Divers. 



Field -characters. — Vinaceous -chestnut throat-patch and grey 

 face and neck are outstanding features of summer dress. In winter, 

 slender bill and white specks on upper-parts are best guide to 

 identity. Jourdain likens cry to short, sharp wail of a hurt child, 

 repeated at intervals. Another note is a hoarse, repeated " kork." 



Breeding-habits. — Often on quite small pools as well as lochs 

 and at times may be met with breeding in considerable numbers 

 both in Norway and Iceland. Nest. — Variable ; sometimes merely 

 a flattened patch on a hummock close to the water ; at other times 

 a mass of wet moss and weeds built up in shallow water or near the 

 margin. Eggs. — 2 normally, though 3 said to occur ; elongated, 



