As seen in the picture it is not the usual bird base, but a new one made from a diagonal fold and a rabbit ear. Simon finds that it is a problem of the traditional bird base that the birds get a hump back. The rabbit ear base avoids this problem. Furthermore the flaps are only symmetric in one dimension which means you get two big flaps and two short. This translates directly into two wings, a short tail and a head with a short neck. Thus the rabbitear base is more suitable for small birds and less for cranes.
Another difference is that the back is not hidden. Thus it should be folded from uni-coloured paper or from paper where the "back side" can be exploited decoratively.