16 WATER BIRDS 



37. PARASITIC JAEGER. — Stercorajius parasiticus. . 



Family : The Skuas and Jaegers. 



Length: 17.00. 



Light Phase of Adults: Top of head and lores dark grayish brown ; rest 



of head and back of neck straw-color, merging into white on throat ; 



breast and belly white, washed on sides with grayish ; back, wings, 



and tail slaty gray ; middle tail-feathers narrow, pointed, and 3.00 



longer than the others ; tarsi black. 

 Dark Phase of Adults: Entire plumage dark brownish slate-color, darker 



on head and lighter on under parts. 

 Light Phase of Young : Head and neckbufFy, streaked with dark ; upper 



parts dark grayish brown, the feathers tipped with buffy ; under parts 



buffy, barred with dark. 

 Bark Phase of Young : Dark grayish brown, darker on wings and tail ; 



neck, belly, and sides streaked with buffy. 

 Downy Young : Soft grayish brown above, under parts lighter. 

 Geographical Distribution : Entire northern hemisphere ; south in winter 



to equator. 

 Breeding Range : Chiefly within the arctic circle. 

 Breeding Season: Approximately, June 5 to July 15. 

 Hest : A mere depression in the ground, rudely lined with grass, dry 



leaves, or moss ; situated on dry upland or rocks near the water. 

 Eggs: 2 to 4 ; pale greenish brown, spotted thickly with umber at larger 



end and somewhat over entire surface. Size 2.23 X 1.62. 



The Parasitic Jaeger occurs commonly as a migrant 

 on the coast of California, though a few remain all winter. 

 Mr. Grinnell reports one taken at Santa Monica, and Dr. 

 Jeffries tells me they are numerous at Santa Catalina in 

 November. They are winter residents in small numbers, 

 also in Oregon, Washington, and British Columbia, and 

 wherever found in sufficient numbers they render life 

 miserable for terns and gulls by snatching their fish from 

 them. At the end of a month's persecution the bodies 

 of the terns become much emaciated from lack of food, 



