Like other pets, your bird can get sick but unlike other pets your birds illness can become serious, even life-threatening, very quickly. If your bird is acting even the slightest bit ill you should get him to your veterinarian right away since birds can go downhill very fast.
Sometimes, however you can get your bird to the veterinarian right away so here are some steps you can take to help care for your sick bird.
first off, you want make sure that you sick bird stays warm. Keep his cage out of many drafts and you might want to try using a grow light ( the same kind you use to grow plants) aimed at the cage but placed in such a way so that your bird can get out of the direct light if he gets too hot.
If you find that your bird is just sitting on the bottom of the cage and is to sick to even sit on his perch, then you might want to move into a hospital cage for better safety. A glass aquarium can make a great hospital cage. Put a towel or some newspaper on the bottom of the cage and put shallow bowls of food and water where your bird can get to it. Newspaper can be kind of slippery so you want to put something that has a little more grit like paper towels on the bottom so that your bird isn't sliding around.
If you can get a freestanding low perch in the aquarium this is perfect in case you bird wants to perch. Position the light so that It shines and to only one side so that the bird can get out of it if he gets too hot.
if you don't have an anti-aquarium readily available than you can make a few changes to your bird's regular cage. Cover most of it with a towel to keep in the heat input the birds food and water dishes on the bottom of the cage where he can get to them. Also, if you have a freestanding parts put this on the bottom two.
You've got to make sure that your bird keeps up his strength as he can easily become weakened by lack of food and water. electrolytes can give your sick bird some quick energy and if he is a hand fed bird then you might see if he'll try taking a few drops of a sports drink from a spoon or eyedropper. If you have a hand feeding formula ready mix that up with some of the sport strength instead of water and see If you'll take that. if you bird is eating on his own make sure that he's getting enough and maybe offer him a tree like a spray millet so that he can get some quick energy. Make sure he also gets enough water.
If you bird is bleeding you need to provide emergency care before you can get them to the vet. Look him over to see where the blood is coming from. While most others do not bleed new feathers that are still growing can bleed. These occult blood feathers and if you do find that the blood is coming from one you'll need to pull the feather out completely. It's a good idea to cover your birds head with a towel while you are doing this. If it's not a feather that's bleeding check his nails and toes and if it's coming from they are applied to styptic powder to the cut. If you don't have styptic powder handy you can use flour In a pinch.
The key to successfully treating your sick bird is getting him to the vet at the first sign of illness. Be sure that you're always watching your bird in checking him for signs of illness. If you notice that your bird Is acting a little different or even look sick it's best to call your bet and get them in right away. It may be that nothing is really wrong with your bird but it's better to be safe than sorry.