DON'T feed it any "people" food.
If you have done well up to this point with bugs/worms etc stick with it.
Anything that a mother bird would hunt and bring home will be fine.
Mother birds don't bring in water to her babies,they get the water they need from the insects that the mother brings it.
Giving this bird water from your tap is giving it water that might have too many chemicals in it. . ie Cholorine.
You can go to Wal Mart to get worms. . . dice them up and feed with a pair of tweezers.
You can also get crickets which I think would be more readily available at a Pet Store.
Food and warmth is the best thing to provide it.
You will need to keep it in a box too big for it to fly or jump out of as it gets bigger and starts to flap it's wings in it's effort to learn to fly.
Now,on the other hand.
Why do people with cats think they have to let their cats roam outside? IF it is YOUR pet why don't you keep YOUR pet at home?
Roaming cats are left to do things like catching helpless baby birds,go to your neighbor's yards and destroy flower beds that they go to dig and pee/poop (if the digging doesn't destroy the flowerbed,their urine will),they dart out in front of cars either getting hit/injured or killed and can cause car wrecks by inexperienced drivers trying to dodge them,they breed like rabbits (usually in your neighbors bushes and keep neighbors awake all night with the breeding screams),they get into fights and get all mangled up,they get into open garbage containers and strow all the trash that gets blown around(remember that the next time you take a drive and see all the blowing trash in a neighborhood) and they carry diseases for which most cat owners don't vaccinate for such as Feline Lukemia which is not cureable and is a certain and lengthy death for cats. (Owlman certainly gives you some good advice. A cat's mouth has soooo much bacteria in it ! ! ! )
I live in the country and I have to deal with others cats ALL the time!
I trap and shoot cats. In the beginning I felt bad that I must be killing someones pet BUT then again I figure if they allow them to roam they have got to know that there is that possibility that the cat. . . their PET could get run over and or kill by a dog etc so they are just braving the odds.
People move out here in my small community and think they have to have cats for "mousing" but the problem is that the cat doesn't know it is to "mouse" at their owners house and they come to my yard and destroy my chickens/ducks.
They don't eat them which I might forgive a hungry cat for doing but they just kill them as sport and then leave me with a dead bird to deal with. . . . explain a dead chicken/duck to a 2 and 4yr old grandchild.
People in the city who have unwanted kittens because they refuse to spay/neuter their cats and now have kittens they can't give away because there are sooooo many of them that they bring the kittens out and dump them off for those of us who live out in the country to deal with.
This issue has become epidemic proportions in our city and we now have a leash law on cats and owners are being fined for allowing their cats to roam.
IF I were to ever own a cat (I'm allergic to cats),it would be my PET and as such I would NEVER do anything that would endanger my PET'S life.
My house cat would be just that. . . .A HOUSE CAT and it would NEVER EVER go outside and it certainly would not be allowed to be a nuisance to my neighbors!
Try taking as good a care of your PET CAT as you are with the new orphaned bird and all of us as pet owners can live in a more harmonious world.
I have 11 Ducks,10 chickens and 2 dogs and manage to keep my animals under control because I am a responsible pet owner.