The one that our friends were borrowing was a Golden Guide to Field Identification of Birds. Here is the cover of the book.
It's an average field guide, with the drawings and maps beside. Occasionally it has a sonogram for a species.
The one our friends gave to us is the Ted Floyd Smithsonian Field Guide to the Birds of North America.
The thing I like about this one is that is has photos instead of drawings. We don't really have any books like this with just photos. The Birds of Canada Book has a small picture in the corner, which is unlabeled for which plumage it is. This is nice, because in some cases I like photos better than drawings.
The Ted Floyd Field Guide is from 2008, and as far as I can tell the other one is from 1986.
I should really get to the last Churchill post, so I hope it will be out soon.