There are three types of jaegers found in North America. The Pomarine Jaeger is the largest among them and has the smallest northern breeding range. The Parasitic Jaeger is the second largest and has the largest breeding range throughout the Arctic. Lastly, the Long-tailed Jaeger is the smallest and easily identified among the three jaegers by its non-streaking flanks and its almost all white head, except for its small black cap.
Jaegers are predators and feed on mice and lemmings found in the tundra. One of their tactics is chasing and harassing gulls, terns, kittiwakes and other smaller birds to give up their food. These birds are easily recognized by their dark brown plumage and the large white area seen on their outer primaries. This being said, the Pomarine Jaeger and the Parasitic Jaegers have many similarities. Given a clear view, one can examine the size and build of the bird, its bill size and length. The Pomarine Jaeger is larger in size and has a heavier bill. The Parasitic Jaeger can be more easily recognized by its noticeably longer tail feathers when sitting on water.