Many animals seem to just have an air about them that says they know no other animal can take them. They have a confidence that no other lesser animal is able to have, because they're at the top of the food chain and will be for the foreseeable future. Larger birds of prey seem to have this around smaller birds, especially since larger birds of prey also often eat smaller birds. I'm sure Josh knows this, so I'm not sure what possessed him to try and ask a hawk for assistance. Of course, Josh has a confidence about him that is not seen in many other animals either.
Also, yes, I know that the size differential is off by quite a bit. In fact, I think that's just the actual approximate size difference between Josh and Lewis. Still, you get the point.