Warblers in general are some of the smallest birds seen in the world. These small jittery birds hardly ever stop moving, almost always hopping from branch to branch, scurrying along the tree trunks and limbs. There are others who live on the ground, hidden in the undergrowths, where you may only hear their songs and not see the birds that are actually singing them.
The non-native Eurasian warbler is a frequent visitor or vagrant to the islands in the North Bering Sea during the spring and fall migration periods. There are at least 14 warbler species that have been identified as a visitor to the North American perimeters.
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.