Echo Hal Michael's recommendation of the Swash & Still guide. Don't know if there's an e-version, but it's much lighter and more compact than an iPad anyway...
Except for swallows, it's a photographic guide, which is nice, tho doesn't always show all ages/plumages. With the paucity of bird species possible, though, it's rarely challenging to find what you're looking for.
Note that it doesn't (my edition, at least) yet recognize the split of Warbler Finch, but it does nicely illustrate both Green & Gray.
Especially helpful was the whale guide, showing photos of all you're likely to see--backs and dorsal fins.

Jeff Bryant
Seattle
jbryant_68 AT yahoo

Sent from my iPad