Kiev TO 'nih; \\\'ri:i< iukds oi' i'i.okida. 



ORDER LONGIPENNES. 



Long- Wing !•: i ) S\\ r m m e k s. 



Famiia STERCORARIID.E. j.i:(;i.:rs. 

 Genls STERCORARIUS I^RissoN. 



189 



^ 



STERCORARIUS PARASITICUS (//////.). 

 Parasitic Jieger. 



Length from base of hook on end of l)ill (unguis) to frontal feathers greater than from un- 

 guis to tip of upper mandiljle. 



Adult {light phase of pliiiiiage) : upper parts slaty gray, a tinge of pale yellow on the sides 

 of the head and neck. Crown of the head and lores .sooty black; under parts white, sliading 

 into slaty gray on sides and lower belly: two middle tail feathers pointed. 



Adult {dark pliase) : general plumage sooty Ijrown ; slightly paler below : crown dark 

 brown. 



I miiiaturc (light phase) : head and neck streaked with buff or gray: under parts mottled 

 and barred with slaty gray : upper parts dark gray : some of the feathers edged with buff. 



I imnaturc {dark phase) : general color slaty brown : neck marked with white: feathers on 

 the l)elly l)arred with dull white. In all plumage the two middle tail feathers are pointed, and 

 the tarsus is blacl< in freshly killed specimens. 



Length. 17 to 20 : Wing, 13: Tail (adult), S. 40, (inunature). 6 : Tarsus. 1.60: Hill. 1.20. 



