The Parasitic Jaeger is very similar to the Pomarine except that the central tail feathers are pointed and are straight instead of twisted.
"The Bird Book" by Chester A. Reed
On August 4, a pomarine jaeger pursued the male loon as it was returning from fishing on Teshekpuk Lake.
"Birds Found on the Arctic Slope of Northern Alaska" by James W. Bee
The pomarine jaeger is most peculiar of shape, especially while flying, and has a cruel-looking beak.
"The Land of Tomorrow" by William B Stephenson, Jr.