My bird threw up white liquid once, then acted normal. What's wrong?

Hello there! Daisy is a beautiful bird. The first thing to discern is whether or not she is regurgitating or vomiting. Regurgitating is voluntary, and usually involved a bunch of head bobbing before spitting out a bit of solid food. Birds commonly do this to people they like. Vomiting looks more like head shaking, followed by liquid being flung from the mouth. If she is vomiting a white substance, this could be a medical problem that needs to be addressed by a veterinarian quickly. Infections in the crop from bacteria or fungus can cause vomiting and dehydration in birds quickly. There are also certain viruses, nutritional deficiencies, and poisons that can cause vomiting. Aside from keeping Daisy warm and calm, there isn't anything else that you can for her if she continues to vomit aside from bringing her to an avian vet. If she just vomited twice and it does not continue, you can probably keep an eye on her for repeat occurrences, but if she vomits again, please consider bringing her to the vet.

Here is a vet that sees birds near you, in case you don't have one yet:
Wellesley Animal Hospital
3430 Lauderdale Dr, Richmond, VA 23233
(804) 364-7030

Good luck, and I hope Daisy gets well soon!