BIRDS. /' 47 



the surface. Off the Yukon mouth they are abundant in .spring, but at all seasons they are rare 

 near Saint Michaels. During the cruise of the Corwin I found them abundant about Saint Law- 

 rcuce Island and everywhere in Bering Straits. 



Along both shores of the Arctic to the north they were very numerous, and to a great extent 

 replaced the other two species. They are especially common along the border of the ice pack and 

 about the whaling fleet, where they fare abundantly. They go south as winter closes in, and un- 

 doubtedly occur at the latter season in large numbers along the Aleutian chain and the adjacent 

 parts of the North Pacific. 



The peculiar twist to the long tailfeatheis of this species renders it conspicuous and ideutiti- 

 able almost as far as seen. 



Stercoraeius PA-RAS^iTicrs (Linn.). Parasitic Jaeger (Esk. Alliikh-tai-yu /?/,). 



This tyrannical bird occurs about the entire coast line of Bering Sea, but it is most numerous 

 along the low, marshy coast of Norton Sound, and thence south to the Knskoquim River. Its 

 breeding range covers the entire region from the Aleutian Islands north to the extreme northern 

 part of the mainland. Upou the Aleutian Islands Dall found them in summer and winter. They 

 were taken during the breeding season on Kyska and Amchitka, near the western end of the chain. 

 They have been taken at Kadiak, and are plentiful from the Yukon mouth up to Nulato and prob- 

 ably above. Elliott found them occurring as stray visitors on the Fur Seal group, and the writer 

 noted them in the Bering Strait vicinity during the summer of 1881. 



During summer these Jaegers show a much greater preference for marshes and the low barren 

 grounds so common in the north than they do for the vicinity of the sea-coast. At the Yukon 

 mouth and near Saint Michaels they arrive with the first open water from the 10th to the 15th of 

 May. The snow still lies in heavy drifts on most of the open country, but the Jaegers take posses- 

 sion and feed upon the shrew-mice and lemmings, which are common on this ground. By the last 

 of Jlay tliey are very common, and twenty or thirty maybe seen in a day's hunt. 



Birds in the black plumage are rare in spring, but are sometimes seen, and at the Yukon 

 mouth on May 31 I found a pair in this plumage mated. The eggs are laid upon the mossy knolls 

 or uplands in their haunts about the 5th of June. The nest is merely a depression in the moss 

 containing two eggs, indistinguishable from those of the next species, and measuring from 2.40 by 

 1.70 to 2 by 1.50 inches. 



The young are on the wing by the end of July and early August. The last birds move south- 

 ward or keep out to sea after the 20th of September. On cloudy days, or in the dusky twilight, 

 these birds have a habit of uttering loud wailing cries, interspersed with harsh shrieks, which are 

 among the most peculiar notes heard in the northern breeding grounds. 



At all times the Jaegers are given to wandering, and one is likely to find them almost any- 

 where along the coast. Thej' are not infrequently seen harrying terns or gulls to make them dis- 

 gorge fish just caught. If successful they dart down and rising under the falling morsel catch 

 it in their capacious mouth. This robbery is often performed by two birds in unison, but whether 

 the birds alternate in disposing of the spoil or not could not be learned. 



When a Jaeger is wounded others of its kind show much concern, and I have secured several 

 birds in succession which were drawn within range by the cries and struggles of their companion. 

 The habits in general of this and the following species are extremely similar along the coast region 

 of Bering Sea, and both breed abundantly on all tiiat broad belt of low barren plains and marshy 

 country bordering the coast along the entire northern end of the continent. This is a common 

 species about Spitzbergeu and Nova Zembla, where it breeds, laying two eggs on the bare ground, 

 on low, unsheltered, and often wet islets or headlands. When surprised near its nest it creeps 

 along the ground with flapping wings to decoy away the intruder. 



They are very greedy, and frequently swallow so much that they are unable to fly until a 

 portion is disgorged. Nordenskjold, from whom the preceding is taken, writes that the Pomai-ine 

 and Long-tailed Jaegers are more common farther east towards Bering Straits. 



This species is more common than pomarinus at Point Barrow where, like the latter, it was 

 not found breeding by Murdoch. This species occurs on the Commander Islands, and is common 

 on the Near Islands, where they breed on Agattii. 



