- Size : It's not a reference manual, it's a field guide. I like to be able to slip it in into my back pocket or easily conceal it in my purse. (You would be surprised what else I keep handy.)
- Drawings vs Pictures: I prefer drawings since they better represent the essence of the species instead of individual characteristics. It is also possible to draw important identification details that are not always visible in a picture.
- Range Maps: Super important, especially if the guide covers a large area (e.g. North America). I prefer them to be on the same page instead of at the back. Who likes additional page flipping anyway?
- Common and Latin Names: A good field guide should have both and that's that.
- A good written description: The description should include specific characteristics such as size, gender distinction, age distinctions, habitat preference, etc.. I also enjoy the additional knowledge of whether the species is edible (mostly for plants) or venomous .
- Built in Ruler: Size sometimes determines the species, nothing better that having a handy ruler you can't loose. (Less important for bird identification since it's mostly done at a distance.)
- Identification Markers: Arrows on the illustration pinpointing specific things to look for (e.g. distinctive markings or coloration).
- Glossary: (or informative introduction to the field) Sometimes scientific words make no sense.
- Index: Preferably with both latin and common names.
- Intuitive Organization: The species must be organized in a way that makes it easy for you to find what your looking for. It depends on the depth of your knowledge on the subject and there are a wide range of options out there ( e.g. by colour, by approximate size, by habitat, taxonomically, etc.).
Here are three of my favorite field guides :
Peterson First Guide to Wildflowers of Northeastern and North-central North America (The Peterson Field Guide Series)
:) Gorgeous Drawings :( No latin names
:) Identification Markers :( No ruler
:) Perfect size :( No range maps
Trees of North America: A Guide to Field Identification, Revised and Updated (Golden Field Guide from St. Martin's Press)
:) 9/10 :( No identification markers
National Geographic Field Guide to the Birds of North America, Fifth Edition
:) Depiction of adult :( No identification markers
(male and female) and juvenile plumage
:) Range maps :( Knowledge of bird taxonomy required for navigation
During my technical degree we were basically brainwashed into swearing by Peterson field guides, now I find that other publications meet my needs better. I'd love to know what you're favorite field guide is why. Do you swear loyalty to a particular publisher? Is your top ten similar to mine? Let me know!