30 MEMOIRS OF THE NUTTALL ORNITHOLOGICAL CLUB 



II [36] Stercorarius pomarinus (Temm.). 

 PoMAEiNE Jaeger. 

 Not uncommon transient visitor. Spring ; July 5 to September 28. 



12 [37] Stercorarius parasiticus (Linn.). 



Parasitic Jaeger ; " Marling-spike " ; " Boatswain." 



Common transient visitor, especially in the fall. June 11 to June 25 ; July 4 

 to October 14. 



This is the Richardson or Arctic Skua of British writers. 



This jaeger has become more common and has come earlier in the summer 

 coincidentally with the increase and earlier arrival in numbers of the terns. It is 

 one of the most interesting sea-birds to watch. At the time they are most abun- 

 dant, namely in August, nearly all are in the usual adult plumage, dark above and 

 snowy white below with a partial dark ring around the neck. Occasionally one 

 is seen in the black plumage, as black below as above, — as black as a crow. Those 

 in the mottled brown plumage are also seen. The long, pointed middle tail 

 feathers of the adult help to distinguish it from the Pomarine Jaeger whose cen- 

 tral tail feathers have rounded ends. Nelson,^ speaking of the latter bird, says : 

 " The peculiar twist to the long tail feathers of this species renders it conspicuous 

 and idenjj^able almost as far as seen." 



My notes of August 11, 1910, at Ipswich, describe a common scene enacted 

 by the Parasitic Jaeger. "Two chased a tern that twisted and turned in sharp 

 angles and small circles over the beach, but finally secured freedom from pursuit 

 by dropping the fish which one of the jaegers skillfully seized in mid-air before 

 it touched the sand. Immediately afterward the two freebooters dashed into a 

 flock of a hundred terns, pursuing them to right and left. The terns screamed 

 loudly and darted about in great confusion, but some of them turned and chased 

 the jaegers." 



Almost always the jaeger catches the booty in the air but I have seen it settle 

 on the water to pick up the fish dropped. 



1 Nelson, E. W. Report upon Natural History Collections made in Alaska between the 

 years 1877 and 1881, p. 47, 1887. 



