Field Guide for all the Birds of North America
Tail Profile of the Jaegers
Labbe
Stercorariidae
Information, images and range maps on over 1,000 birds of North America, including sub-species, vagrants, introduced birds and possibilities
Jaegers can be easily be identified from each other in breeding plumage by examining the tails feathers of the seabirds. Although, the species can vary in plumage colours, ranging from light morph, intermediate morph and dark morph, the shape or profile of the tail feathers are the same for each species, but different from the other two types of jaegers. This is not as easy when the seabirds are seen in non-breeding plumage, or the jaeger is a juvenile. In these cases the tail feathers might be much shorter, and less prominent, or not visible at all.
References to Other Bird Sites:
Avibase - the world bird database This site provides the user with a complete list of bird species, broken down per country, or in the example of the US or Canada, per state and province. Here, bird species names are available in other languages, a great asset to be used as a translation of foreign bird names.
ABA - American Birding Association This site represents an organization that maintains official records of all birds species that have been proven to have been seen inside the perimeters of the North American Continent and the surrounding bodies of water. Regular revised versions are posted to keep the bird list current at all times. This is the list used by all serious birders over their lifetime. You may be aware of the movie called the "Big Year". It was with this list that all the competing birders used in an attempt to set a new record as to how many bird species that could be seen by an individual birder in one calendar year.
I hope you will take advantage of these suggested websites. I have used each of them, in one way or another, throughout the years in my quest to better identify and understand our fine feathered friends.