you really have a killer cat. My cat has only very small presents... dragonflys, frogs, rats...
but the biggest was a female Chaffinch i think
http://en.wikipedia.org/wiki/Chaffinch
so my cat is very bad in catching something. Luckily the chaffinch had a little scratch on the right wing and lost some feathers. He got panically lost in the kitchen, i came in, closed the door and opened the window. The bird was playing dead and didn't try to escape. so i took some corn we had stored in the kitchen and layed it on the kitchen table. Bird wasn't eating it but it gave him enough courage to spread his wings and fly through the window (interestingly it showed me, that the bird was clever enough to notice, where the fresh air was, didnt flew against the closed window next to the opened)