How do you know if your bird has mites? Excessive scratching could be the first clue, but that could also be attributed to dry skin. The simplest method is to take a piece of white computer paper and hold it under your bird’s main perch. Then tap, tap, tap hard on the perch with something like a wooden spoon. If you see small red dot “crawly things” on the paper, those would be mites. If you’re in doubt a visit to the vet would be in order.
If your flighted bird is startled, it’s first instinct is to fly–and that’s how you lose it. (A (properly) trimmed bird can still fly, just horizontally and down…)
Or it’s just flying around when company arrives, front door is open, your bird flies out. Every spring, an incredible number of lost cockatiels (usually small birds), is reported. Breaks my heart. Never found, either.