48 MICHIGAN BIRD LIFE. 



"Female. Detroit River, May 30, 1879. Killed by R. Sanlier. It was 

 chasing Black Terns near Fighting Island." 



The name appears in several lists of birds of the state, and there can be 

 little doubt that the species occurs with some regularity on Lakes Superior, 

 Michigan and Huron. Mr. E. W. Nelson states that he is "certain that 

 this species is a rare visitant to Lake Michigan during severe winters" 

 (Bull. Nutt. Orn. Club, Vol. I, p. 41). Dr. Brayton (Trans. Ind. Hort. 

 Hoc. 1879 p. 150) says "A rare winter visitant to Lake Michigan. October 

 9, 1876, in company with my friend Mr. E. W. Nelson * * * we saw 

 a fine specimen of this bird flying along the lake shore near the state 

 (Indiana) hne." As already stated the bird preys upon other birds, robbing 

 their nests of eggs and young or chasing the old birds and compelling them 

 to give up the food they have taken. 



The above record for Detroit River, May 30, shows that the bird lingers 

 late in these latitudes, but it nests invariably far north, and its nesting 

 habits are but imperfectly known. It lays two or three olive green to olive 

 brown eggs more or less spotted with darker brown and black. The eggs 

 average 2.35 by 1.63 inches. 



TECHNICAL DESCRIPTION. 



A web-footed, gull-like seabird, with bill more strongly hooked than in the ordinary- 

 gulls) and with the two middle tail-feathers projecting beyond the rest. These 

 two feathers are nearly as broad as the rest, rounded at tip, and from 7 to 10 inches 

 long. The adult often has the upper parts, except the nape, dark slate, and this color 

 extends over the sides of the head. All the lower parts from bill to tail are white or yellow- 

 ish white, and this is also the color of the nape. Some adults, however, are almost entirely 

 slate-colored above and below, often appearing dull black; the greater number are inter- 

 mediate between these two extremes. Immature birds are similar to adults, but are 

 always thickly barred with dark brown below and rusty or yellowish white above. Length, 

 20 to 23 inches; wing, 13.50 to 14; culmen, 1.45 to 1.75. 



9. Parasitic Jaeger. Stercorarius parasiticus (Linn.). (37) 



Synonyms: Richardson's Jaeger; Teaser; Boatswain; Marlinspike. — Larus parasiticus, 

 Linn., 1758. — Lestris parasitica. 111., 1811. — Lestris richardsoni, Nutt., 1834, Aud., 1835, 

 — Stercorarius parasiticus of most recent authors. 



This bird is very similar to the Pomarine Jicger in general appearance 

 but is smaller and has the two middle tail-feathers narrow and pointed, 

 as well as elongated, which is readily seen when the bird is in full chase 

 after a gull or tern which is dodging and twisting in the attempt to escape. 



Distribution. — Northern part of the Northern Hemisphere, southward 

 to North Africa and South America. Breeds in high northern districts, 

 and winters from New York and California southward to Brazil. 



Like the preceding species this a decidedly uncommon bird in Michigan. 

 While it probably occurs regularly in spring and fall we know of but two 

 unquestionable records. A specimen was killed at Otter Lake, Lapeer 

 county, Sept. 28, 1897, and mounted by Robert P. Stark of that place, 

 from whom it was obtained for the museum of the Agricultural College, 

 where it now is. This is an immature bird, probably a bird of the year, 

 and the sex was not determined. Another specimen was taken at Point 

 Mouville, Detroit River, Nov. 27, 1903. It was found by Mr. Covert at a tax- 

 idermist's shop in Detroit, and identified by himself and Mr. B. H. Swales. 

 It is now in the collection of the Detroit Museum of Art (Bull. Mich. Orn. 



