22 BULLETIN 113, UNITED STATES NATIONAL MUSEUM. 



be unable to fly, but they manage to increase the distance from their start ^° g 

 point at a very respectable rate, and ere long suddenly launch forth 

 wing. 



Mr. Hersey found a nest of the long-tailed jaeger, with two eggs 

 on the point of hatching, near St. Michael on June 19, 1915. The 

 eggs were laid in a natural depression of irregular shape on the top 

 of a dry mound slightly raised above the surrounding wet tundra; 

 there were several higher mounds within a few yards. The female 

 could be plainly seen sitting on her nest from a considerable dis- 

 tance. She allowed him to approach within 20 yards before she 

 flew, when both she and the male swooped about his head. Within 

 50 feet of this nest a willow ptarmigan was sitting on her nest with 

 six eggs. 



Mr. Johan Koren, according to Messrs. Thayer and Bangs, (1914), 

 found a remarkable nest of this species, in northeastern Siberia, on 

 June 22, 1912. 



The eggs lay in a slight depression on the level, mossy ground . in a dry, 

 high, larch forest. Both parent birds were present, and both had acquired 

 the habit of alighting and perching in the tree tops. 



This was a decided exception to the rule, however, as the nest is 

 usually placed on some slight elevation on the flat or rolling open 

 tundra, where a few pieces of dry grass, bits of mosses or leaves 

 are scraped together in a slight hollow. The birds are very courage- 

 ous in the defense of, the nest, swooping down at the intruder or 

 flying straight at his face and turning or rising just in time to miss 

 striking him. After the young are hatched, however, they become 

 more cautious and seldom approach within gunshot, lest they betray 

 the presence of the young, which are cleverly hidden in the grass. 



Eggs. — The long-tailed jaeger lays almost invariably two eggs, 

 occasionally only one, and very rarely three. The eggs are almost 

 indistinguishable from those of the parasitic jaeger, but they aver- 

 age slightly smaller and are usually a little more blunt in shape. 

 The shape varies from ovate to short ovate; usually nearer the latter. 

 The shell is smooth and thin, but has very little luster. The ground 

 color varies from " light brownish olive " or " Dresden brown," in 

 the darkest eggs, to " tawny olive," " Isabella color," " light yellow- 

 ish olive," or even " olive buff," in the lightest eggs. The eggs are 

 irregularly spotted or blotched, chiefly about the larger end with 

 " raw umber," " Prout's brown," or other lighter shades of brown. 

 Often there are also numerous underlying spots and blotches 

 of various shades of drab. The measurements of 48 eggs in the 

 United States National Museum collection, average 55 by 39 milli- 

 meters; the eggs showing the four extremes measure 61.5 by 42.5, 

 56 by 50, 47 by 38.5, and 49.5 by 36 millimeters. 



