Know the common plants that must move out
Start with the plants most often found in homes and most often implicated when birds chew something harmful. Avocado in any form, including a stone sprouted in a jar on the windowsill, is dangerous to birds and should never share a room with one. Lilies, philodendron, pothos, dieffenbachia, peace lilies, oleander, ivy and asparagus fern all need to live behind a closed door your bird never enters, and bulb plants such as daffodil, amaryllis, hyacinth and tulip are risky in both leaf and bulb. This is not a complete list, so a plant being absent from it does not make it safe; it is a removal list for the usual suspects already sitting in most flight rooms.
Think like a flighted bird when you place plants
A plant is only out of reach if a flying, climbing, determined bird truly cannot reach it, which rules out most shelves, curtain rails and the tops of bookcases in a flight room. Birds land high, walk along edges and lean out to strip a leaf that hangs within beak stretch of a perch or cage top, and they shred for pleasure as much as for food, so a bird does not need to be hungry to poison itself. The clean rule is that a free-flight room contains no risky or unidentified plants at all, and any plant you love moves to a room the bird never enters rather than to a higher shelf in the same room. Check hanging baskets too, because trailing pothos and ivy lower themselves into reach as they grow.
Offer safe chewing so leaves are less tempting
Birds chew because chewing is normal, healthy behaviour, so a flight room with nothing permitted to shred makes houseplants more attractive, not less. Provide untreated branches from bird-safe trees, plain cardboard, cork, yucca pieces and paper toys, rotated often enough to stay interesting, and place them where your bird already likes to sit so the legal option is also the convenient one. Grow a small pot of bird-safe grasses or herbs in the flight room if your species enjoys fresh greens, chosen carefully for birds and grown without sprays, so foraging energy has a safe green target. Even with good alternatives, supervision still matters, because no toy competes perfectly with a forbidden leaf.
Respond quickly if your bird chews the wrong plant
If you find your bird chewing a plant on the risky list, or an unidentified plant, remove it calmly, note the plant's name or photograph it, and watch closely for drooping, loss of appetite, changed droppings, vomiting, weakness or breathing changes. Contact an avian vet promptly for advice rather than waiting for clear signs, and take the plant or its photo with you if you are asked to go in, because identification changes what the vet will do. Do not try home remedies or induce anything yourself. Afterwards, audit the whole room again with fresh eyes, and whenever a gifted or newly bought plant arrives, settle where it can safely live by putting one more question to KinsLe's Kinny, whose replies are pulled from the library behind KinsLe Answers.