704 A PRACTICAL HANDBOOK OF BRITISH BIRDS. 



About half tibia bare, tarsus short, toes short, three front ones 

 connected by concave webs, hind toe free, claws concave and curved 

 and middle one dilated. Bill almost straight, much compressed, 

 tapering to sharp point, gonys long and gently sloped up to tip, 

 angle rather prominent. Nostrils basal, slit-like. 



Soft parts. — Bill black, tip horn-yellow ; legs and feet black, 

 soles yellow ; iris dark brown. 



Characters and allied forms. — S. s. acuflavida (N. America) has 

 more black and only very narrow white line along inner edge at tips 

 of primaries, especially noticeable on 3rd to 5th. Long black bill 

 with yellowish tip distinguishes this from other British Terns. 



Field-characters. — Larger than other common British Terns. 

 In repose, black feet, black yellow-tipped bill, occipital crest, com- 

 paratively long tarsus, and gull -like pose distinctive. In flight, 

 tail shorter and less deeply forked, and wings longer and narrower 

 in proportion than in Common, Arctic, or Roseate. Usually plunges 

 from greater height and remains submerged longer than smaller 

 Terns. Call -note a loud grating " kirr-whit " ; alarm-note a 

 reiterated " gwit " or " gwut." 



Breeding-habits. — Nests in colonies on low-lying islands, sand- 

 dunes, and sandy shores. Nest. — Generally a mere hollow scratched 

 in sand but marram-grass also used at times freely. Eggs. — 

 Normally 2, often 1 only, and occasionally 3, varying from creamy- 

 white to warm brownish, sometimes unmarked or spotted, blotched 

 and smeared with blackish-brown or reddish -brown and ashy-grey 

 shellmarks. Average of 100 eggs 51.7x36.1. Max. : 55.6x36.2 

 and 53.2 X 39. Min. : 44 X 34.7 and 51 X 33.4 mm. Breeding -season. — 

 Exceptionally end April, usually from early May onward, most 

 laying latter half May. Incubation. — By both sexes. Period 20-21 

 days. Single brooded. 



Food. — Small fish: young frequently fed on "sand-eels" 

 (Ammodytes) but other species such as whiting, sprat (Clupea), 

 weever (Trachinus), etc., found by nests, and remains of gar -fish and 

 herrings up to 5 in. long also taken. 



Distribution. — British Isles. — Summer -resident (end March (early 

 date Mar. 18, 1913, Cornwall) to end Sept.). As passage -migrant 

 (end March to end April and mid- July to end Sept. (late dates Oct. 1 1 , 

 1910, Yorks., Oct. 23, 1911, Edenmouth, Nov. 16, 1910, Fife)) occurs 

 many parts of British coast and occasionally inland. England and 

 Wales. — Large breeding colonies Fame Isles (Northumberland) and 

 Ravenglass (Cumberland). Breeds Walney Island (Lanes.) and 

 Anglesey and only occasionally Kent. Scilly Isles, Suffolk (1906), and 

 Norfolk (1893, 1921, and in 1922 many pairs) and has ceased Essex. 

 Scotland. — Breeds Kirkcudbright and Wigtownshire and sporadic- 

 ally in Clyde area and on east coast, also breeds Sanday (Orkneys).* 



* The Eev. J. R. Hale informs us that it breeds on Sanday end not North 

 Ronaldshay, as stated in Saunders's Manual. 



