From the box cover:

"The Field Mark Identification Game

The most innovative bird watching aid since the invention of the pocket field guide--a simulation of a spring day at one of North America's best birding spots.

Designed by naturalists to teach you behavior and flight recognition, plumage and vocalization identification, use of field guides and checklists, and more, without using flash cards or trivia.

BIRDING!...will help you to improve all the skills used in the field."

Every player moves their pawn on the map of Point Pelee. Then the dealer reads the description of a bird species from the top card of the deck. Everyone occupying the habitat type given on the card is, in turn, eligible to guess the species. If you're right, tick its box on your checklist of 292 possible species. Per the rules, "The player (or team) with the most species identified on the Checklist at the at the end of the game wins."