634 ARCTIC TERN. 



Spitsbergen ; while in Asia as well as in America it is completely 

 circumpolar in its range. On migration we trace it along the 

 Atlantic sea-board to the Canaries and the Azores — -a straggler occa 

 sionally penetrating into the Mediterranean as far as Italy; it descends 

 the coast of Africa to Table Bay, and I have a specimen which flew 

 on board Lord Crawford's yacht ' Venus ' far to the south-east of 

 Madagascar. The islands of the Southern Ocean are inhabited by 

 two nearly-allied but well-defined species, while there is a third 

 representative in South America; on the west coast, however, Staff- 

 Commr. MacFarlane, when in H.M.S. 'Constance,' obtained a 

 genuine Arctic Tern off Arica. It breeds plentifully in Alaska, and 

 occurs in Kamschatka and Amur-land ; though there — as well as in 

 Japan, and in Siberia as far as Lake Baikal — the representative species 

 is S. longipennis, which has a black bill, small dark brown legs and 

 feet, and grey under surface. 



The eggs, laid in a mere depression of the sand or scanty herb- 

 age, or even on the bare rock just above reach of the waves, are 

 sometimes 3 but often only 2 in number ; they are slightly smaller 

 than those of the Common Tern, measuring about i"6 by i in., and 

 are subject to rather more variation in colour, a pale bluish-green 

 being frequent, while a rich ochre-red with rufous-brown spots is 

 occasionally found. In defence of its nest the bird is very bold, 

 striking the intruder sharply with its beak, and a flock has been seen 

 to mob and drown a Hooded Crow. In food and general habits it 

 does not differ materially from the preceding species, and both may 

 be seen dashing down with such force as to raise a cloud of spray, 

 which momentarily hides them from the view of any one on nearly the 

 same level ; but, from an eminence, I have never witnessed complete 

 submersion, though in this respect the e.xperience of the Rev. H. A. 

 Macpherson differs from mine. 



The adult in summer may be distinguished from the Common 

 Tern by its blood-red bill, distinctly pearl-grey under parts (without 

 any vinaceous tint), and longer lateral tail-feathers. At all ages its 

 shorter tarsi are characteristic, though the difference is not invari- 

 ably so great as some writers have supposed ; a better distinction 

 being the nan-owness and pale colour of tlie stripe next the shaft oti 

 the itmer uieb of each of the long primaries ; this stripe being much 

 broader in S. fliiviatilis. The young of both species go through 

 similar seasonal changes. The legs and feet are coral-red in spring 

 — duller in the young — and nearly black in winter. Birds a year or 

 more old have a dark bar on the carpal joint until the autumn moult ; 

 they breed the following June. Length i4'5 in. ; wing 10 in. 



