Reddit reviews The Sibley Guide to Birds

Personally, I like the National Geographic Guide to the Birds of North America for a guide that you can carry.

Sibley's is the definitive best guide, but is more of a desk reference. It's a bit big to carry around. Though, there is also a Sibley's app if you like to have the guide on your phone.

I prefer Kaufman's field guide for carrying with me while I'm birding. It's well organized and has a lot of great info/illustrations:

http://www.amazon.com/Kaufman-Field-Guide-Birds-America/dp/0618574239/ref=sr_1_1?ie=UTF8&qid=1382709486&sr=8-1&keywords=kaufman

At home, I like to use Sibley's book (which is far too large to carry with as a field guide). It has even more illustrations and is a bit more in depth than Kaufman's field guide due to its size:

http://www.amazon.com/Sibley-Guide-Birds-David-Allen/dp/0679451226/ref=sr_1_1?ie=UTF8&qid=1382709539&sr=8-1&keywords=sibley+guide+to+birds

This is a great one if you're interested in just raptors. My local Barnes and Noble has it, too. If you want lots of bird species, a trusted favorite is Sibley's.

For field guides the more generalized ones are usually easier to get a hold of. A few you could look at are from National Geographic, Peterson, and Sibley. There are also some books for getting started, such as Sibley's Birding Basics. Backyard Bird guides are also a good place to start.

For North Dakota specifically I found this great pdf that covers all the basics of bird watching, and this field guide. Hope this helps!