8 BULLETIN 113, UNITED STATES NATIONAL MUSEUM. 



means the most aggressive. Few of us have ever seen it on its breed- 

 ing grounds, which lie within the Arctic Circle, where it is widely 

 scattered over the boundless plains of the marshy tundra. 



Spring. — Dr. E, W. Nelson (1887) says of its arrival in northern 

 Alaska : 



The earliest arrival of this bird in spring was May 13 at the Yukon mouth 

 where the writer found it searching for food along the ice-covered river chan- 

 nels. They became more common, until, by the last of the month, from a dozen 

 to 20 might be seen every day, 



Mr. Frank C. Hennessey, who accompanied the A. P. Low expedi- 

 tion to the regions north of Hudson Bay, says, in his notes, that " the 

 first of this variety was seen to arrive in the spring at Winter Har- 

 bour on May 29th." 



Nesting. — Very little has been published on the nesting habits of 

 the pomarine jaeger. Mr. Hennessey, in the notes referred to above, 

 which he kindly sent me, states that these birds are " abundant about 

 Winter Harbour, where they breed on the low, flat, marshy land in 

 the neighborhood, choosing the small mounds or slight elevations that 

 abound in these places upon which to rear their brood. The nest is 

 a slight depression in the soil of the elevation and just deep enough 

 to admit the eggs and breast of the bird. No material is used in its 

 construction, but the bottom is covered with much loose soil and rub- 

 bish apparently blown in accidentally." Mr. C. Boyce Hill (1900) 

 published the following account of the nesting habits of this species 

 in Siberia : 



On our way down the Yenisei the steamer which was towing us fortunately 

 ran ashore on one of the numerous sand banks which abound in this river. I 

 say fortunately because it enabled us to discover this skua nesting. After 

 having inquired the probable duration of our stoppage, Popan and I agreed to 

 explore the small islands near at hand — a grovip named the Brekotsky. We 

 took one each, and on mine, a large, flat marsh, I observed a Pomatorhine skua, 

 which was presently joined by another. The birds did not appear at all demon- 

 strative nor to resent intrusion, like the long-tailed skuas, so I thought they 

 could not be nesting. But after much searching and watching I observed one 

 settle right in the center of the marsh, so at once proceeded to the spot. The 

 bird rose when I was within a few yards of it, and to my delight I saw the 

 nest with two eggs. I waited a few moments for the skua to come within shot 

 and killed it ; after pursuing its mate, I captured that also. The nest was a 

 mere depression in the ground, on a spot rather drier than the surrounding 

 marsh, and to reach it I was at times up to my knees in swamp; so that had 

 it not been for a foundation of ice at a depth of from 18 inches to 2 feet from 

 th« surface I do not think I should have been able to record this event. I 

 also found nesting on this island some scaup ducks and red-necked phalaropes. 



Mr. Ludwig Kumlien (1879) found this species breeding on the 

 Greenland coast under very different conditions. He writes : 



I have, however, nowhere found them so very common as on the southern 

 shores of Disko Island ; at Laxbught and Fortuna Bay there must have been 



