Cockatiels, just like humans, can develop colds. They will not be able to tell you they are ill but there are behaviours you can watch out for – such as a loss of appetite, watery eyes and sneezing.
Sometimes ill cockatiels refuse to feed themselves – in these cases you need to learn how to hand-feed them correctly. A cockatiel’s diet must be mostly seed mixture but also some parts fruits and vegetables such as sweet corn and apple.
If your cockatiel is extremely resistant to eating, tempt it with a few foods that are usually only given to it as treats. Stop hand-feeding as soon as the bird seems like it is well enough to resume feeding by itself.
If your cockatiel is sharing its cage with any other birds, you should isolate it immediately so as to prevent the cold spreading to the others. Make sure wherever the cockatiel is – usually a cage – is adequately heated, as they need warmth to return to their correct body temperature. To keep the cage heated, try suspending a lightbulb above it.
At some petshops you can buy antibiotics designed specially for birds such as terramycin. This can be added to in a solution to your bird’s water.