Back in the old days, that meant a huge, hard-covered tome... and I have one of those — a large dark volume, filled with drawings.
When I first started birding, I found photographs easier to use as references, though, and so my reference website of choice and the books I used most featured actual pictures. (I also prefer smaller books that can easily be held and read on the fly, so my book choices are rather stout paperbacks.)
With time, however, I started looking for more nuanced description and key features, and books with illustrations can be superb for this.
Here are some suggestions for bird guides:
- A Land Manager's Guide to Grassland Birds of Saskatchewan. Looks like a Govt. publication, now housed at the South Saskatchewan River Stewards site. Lots of information about our birds, with line drawings, maps and details about food and preferred habitats.
- Cornell University's All About Birds is very comprehensive, easy to follow and clear.
- I've sometimes found What Bird to be helpful.
- Audobon Birds links to e-bird, a reasonable birding app.
- ARKive.org features stunning photos and videos, with lots of information. Focus is on endangered species, including birds.
- The Sibley field guides (illustrations).
- Peterson field guides (illustrations).
- Stokes field guides (photographs).
- National Geographic Field Guild to the Birds of Western North America (Saskatchewan is in an overlap area for this guide series, so the Birds of Eastern North America may also be useful.)
- National Wildlife Federation Field Guide to Birds of North America.
- The old Golden Guide to Field Identification: Birds of North America. (With drawings, not photographs; key virtue = very small.
- Audobon Birds: A Field Guide to the Birds of North America. This is linked to eBird, and provides great info on local sightings.
- iBird: Another good app, with a great search function that recognizes which birds are common where, and when.