My reply about lens comes from the fact that the OP is asking what camera to buy, not what lens to buy,
Precisely. The OP has his lens, the question was which body do I put it on. In fact the OP specifically stated he wasn't interested in an L lens. The best choice for the stated purpose of bird photography is the 7D due to its autofocus and frame rate. Its better build and longer life shutter will also help it maintain value down the road.
Is the 70-300 a bit short? Of course but the 7D crops well so it will do until the OP gets more into the challenge of BIF photography. Then he can pose a lens question based on his greater experience. Right now the bang for the buck is the Sigma 150-500.

