The objective of the game is to build a collection that contains 7 different species, or three (or more) each of two different species.
A game plays in several rounds. At the beginning of each round, each player starts with 8 cards in their hand and there are 4 rows with three cards faceup at the center of the table. The game starts with the dealer and go clockwise. Also, each player starts with a bird card, faceup, in front of them, which represents the first Bird in their collection.
On their turn, a player must lay one or more birds from their hand. All the birds of the chosen species that player has in their hand must be played. The player lays these birds (next to each other) on the left or the right side of one of the 4 rows at the center of the table. When a player places a bird in a row that already has one or more Birds of that species, the player must take all the cards between these birds into their hand. After taking the surrounded cards, the remaining birds are moved together and new cards are added (placed on the left or the right) from the draw pile to this row until there are two different species in it.
If no cards were taken, the player may choose to draw two cards from the draw pile.
Complete a flock (optional)
A set of birds of the same species (a flock) that the player hold in their hand may be revealed to add one or two of this cards to their collection.
Each card has two numbers, the lower representing the number stated for the small flock and the higher representing the number stated for the big Flock. When the number of revealed cards is higher or equal to:
- The Small Flock: the player adds one of the revealed cards to their collection;
- The Big Flock: the player adds two of the revealed cards to their collection.
The remaining cards are placed into the discard pile. On their turn, a player can only complete a single Flock.
(Note that the BGA implementation gives a few seconds of "thinking time" for this decision even if you cannot play a flock, so that your opponent cannot tell whether you have an unclaimed flock in hand.)
End of a round
A round ends when one of the players has no cards left in their hand. The remaining cards that players have in their hand go to the discard pile. The cards laid in rows at the center of the table remain in place. The player who ended the round becomes the new dealer.
End of the game
If a player collects 7 different species, or three (or more) each of two different species, they win.
If it is impossible to deal 8 cards to each player (even with the discard pile), the game ends immediately. In this case, the player with the most bird cards in their collection wins the game.