eBay is the ready answer for the 1/6 Little Birds. They pop up frequently, some times at very reasonable prices.
The key for a reasonable price is to try your search with every odd, off the wall, item description. Frequently the seller doesn't know what he has and descriptions can get crazy.
As far as I remember, 21C made two versions, one in black and one in OD green. I have the black, which I believe is the more common bird.
The killer here is the shipping. The box is very large.
It's a great item, especially with a crew.
TTT
Sometimes I am the windshield, sometimes, I am the bug.