Are you sure it's vomit and not regurgitation? They can look very similar. Regurgitated food has a mushy look to it and usually happens when a bird is showing mating behaviors. If it's vomit, it should be more liquid-y than solid and your bird will display other symptoms of sickness like tiredness and fluffed up feathers, loss of appetite and not acting like their usual self. If you are sure that it is vomit, than I would recommend that you contact your vet. Your bird should not be vomiting. However, regurgitation is normal and should not be encouraged.