I just visited this Web site for the first time. It is very well done, good photos and interesting info.
http://nationalzoo.si.edu/Animals/Birds/
From the site - The tiny Blackpoll Warbler is about 6 inches long and weighs about 1/2 oz.
During fall migration this amazing bird takes an over-water non-stop flight from southern Canada or the coast of New England to its winter home in the Caribbean or South America. This is a distance of about 2000 miles.
During this trip the Blackpoll stays aloft for about 80-90 hours. No soaring for this little guy, it is a lot of wingbeats all the way.
If a Blackpoll Warbler were burning gasoline instead of reserves of body fat, it could boast of getting 720,000 miles to the gallon!