There have been many recent press reports of work done by Dr Bill DeLuca of the University of Massachusetts. On the migration of the Blackpoll Warbler.
Please find a description of this work here:
Animalnav.org has been talking about very long migrations of birds over the ocean for a long time and especially the migration of the bar tailed Godwit. It is very nice to have proof that birds can do these enormous journeys (1700 miles) in one journey without stopping, because these warblers are not equipped to stop on the sea.
There is astonishment that these birds suffer very high casualty rates of up to a half but we think that most migratory birds have quite high birth rates (the blackpoll warbler has 3-9 eggs per clutch) so that they can tolerate high losses, they only need two survivors per clutch to keep the species alive.
The shortest distance for this migration between the high arctic summering grounds of Canada and the North Western part of South America (Venezuela, Cuba and Columbia) is over the open ocean. We are still searching to understand how they know how to navigate over these huge distances of open ocean.