Bird Checklists of the United States
http://www.npwrc.usgs.gov/resource/birds/chekbird/chekbird.htm
BIRDNET
https://birdnet.org/
Ornithological Worldwide Literature (OWL)
http://egizoosrv.zoo.ox.ac.uk/owl/
Ornithology.com
http://www.ornithology.com/
Searchable Ornithological Research Archive
http://elibrary.unm.edu/sora/
Smithsonian Migratory Bird Center
http://nationalzoo.si.edu/ConservationAndScience/MigratoryBirds/
Where to Bird: Vermont
http://www.birding.com/wheretobird/Vermont.asp
