Need to know:

If a cat caught a bird, it does not look good for the bird. Even if it looks perfectly fine!
Releasing that bird would be a death sentence! Don´t do it!
The reason is that cats have bacteria in their mouth and also under their nails that are 100% deadly to a bird.
This bacteria is called “Pasteurella multocida”
A bird does not have any chance of winning the fight against this bacteria and death will follow within a few hours until 24 hours depending on the situation and the bird species.
Every time you saw someone “save” a bird from a cat and release it…that bird died! Almost for sure!
Mind boggling, isn’t it! Why don’t they teach us about this in schools?

What to do?

If the bird looks fine apart from contact with the cat, it does not mean that the bird is fine.
If you have access to a rehabber or veterinarian, make sure to give them a call to check out if they want to help you by determining if the bird is really fine.
The most important is to get antibiotics, as soon as possible! A broad spectrum antibiotics like Baytril (enrofloxacin is the active ingredient) would increase the survival chances a lot! (the amount you have to give can be found on this website). 5 days should do the trick!
The problem is of course that you only can get the antibiotics instantly via a veterinarian.
Call ALL your friends and family members and/or put on facebook if someone has Baytril for cats or dogs at home!). An open package that has been saved in the fridge would still be good half a year later.
Maybe the vet is unwilling to help or closed so searching for Baytril would be a good idea even if you booked a time with a vet for the same day!

BEST OF LUCK! Let me know if this guide helped you out: