What sort of camera do I need to obtain these sorts of shots?

Nice equipment is great to have and can make things easier, but I have noticed that there are some photographers that use the basic equipment and do much better than I ever could.  I think learning to get the most out of the equipment you choose and learning about the birds habits you are photographing can go a long way.  HERE is a link to a photographer that uses a Rebel XTi and a Tamron 200-500 lens and comes away with great results.  Gives hope to people like me...... but I have a long way to go to master my equipment.