Free today (1/14/14)
Over 2,000 beautiful color photographs detailing each species
Advanced search and browsing with multiple variables such as size, region, zip code, color, habitat, and more
Audubon Butterflies is your essential guide to over 600 butterflies of North America. Now you can identify every species in your backyard, parks, gardens, the woods or fields with thousands of professional color photographs.
I have most of the Audubon apps including this one and find them useful. Regular $4.99