Ask everyone to find a partner so everyone is paired up in groups of two.
Have them decide who is the birdie and who is the perch.
All the birdies stand in a circle and all the perches stand in a circle surrounding the birdies. Have some music ready.
When the music starts, the birdies walk clockwise around the circle and the perches walk counter-clockwise.
When the music stops, the birdies must find their perches and sit on them (the perch kneels on one knee, making a perch out of the other leg).
If you don't have music, you can just have a leader yell "Birdie on a Perch!"
The last couple to pair up is eliminated and the object is to be the last couple left.
It's more fun if you make them move quickly in their circles so that they are at least jogging.