Cockatiels are one of the smallest types of pet to own, so you will need to keep an eye on your existing pets to make sure that they do not harm your new cockatiel.
In most cases dogs will not be a problem for your cockatiel, as dogs will generally ignore the bird. If however your dog takes to chasing your bird, you will need to separate them.
Cats on the other hand are more likely to harm your bird, as they are natural predators, and birds are one of their food sources along with other rodents. They will usually wait for the bird to be removed from the cage before trying to catch it. Some will even be so bold as to climb onto the cage and attempt to reach it through the mesh. Although this may not cause direct harm, it will upset your cockatiel, which may injure itself by flapping around its cage.
A tame bird is especially vulnerable to a cat, as its natural fear is lessened. Try to keep your cockatiel in a room that your cats aren't allowed into, and if letting your cockatiel out of his cage, first check that the cats aren't around. Never be tempted to leave the bird unsupervised in the room, even for a short time, especially if you have children. They could open a door and let the cat in by accident, which could well spell the end of your bird.
Open fish tanks can present another hazard for your cockatiel. If the bird falls into the tank, its plumage will become saturated, which will cause it to sink and drown. To avoid an accident, make sure the fish tank has a cover over it at all times.
If you own a parrot or bird of another species, you will need to introduce them very slowly. Jealousy could make your established pet parrot attack the new cockatiel. The established bird may call loudly while you are working with your new cockatiel, and if the cockatiel lands on his cage, he will attempt to bite his feet through the meshing. If the cages are placed close together, the established bird may also try to bite the cockatiel through the cage bars.
In order to reduce conflict, try to spend more time with your established bird. Try letting both birds out together, and this may reduce aggressiveness, and in time they may form a close bond, perhaps even roosting side by side in the same cage.
There is no chance of your birds cross breeding. They have never in history been successfully cross bred with any other species, as they are so different to the other bird species.
Author Resource:-
Michel Maling has owned pet birds, mainly parrots and cockatiels since childhood. Educate yourself and learn to care for your cockatiel properly. Visit http://cockatielsaspets.com