The short answer for a canary
A canary's cage belongs in a bright, calm corner of a room people actually use, set against a wall, raised to about chest height, and kept well away from the kitchen. That one placement decision protects a canary three ways at once: the wall behind the cage gives a small songbird a secure side to retreat toward, the distance from cooking keeps the strongest household fumes away from very efficient lungs, and a lived-in room gives the bird company and daylight without being surrounded by passing feet and reaching hands on every side.
Why a canary's lungs set the rules
A canary breathes far more efficiently than a person does, moving air through its body in a way that also moves whatever is floating in that air deep into its system. That efficiency is why canaries were once carried into mines as living alarms. In a home it means a canary can be harmed by airborne products an owner barely notices: overheated nonstick coatings, smoke, strong fragrance, and fine spray mists. A canary cannot leave the room, open a window, or hold its breath, so the air quality around the cage is the owner's job in a way it simply is not for a dog that can wander into another room.
Walking the room before the cage goes down
Stand where the cage would go and look in all four directions before you commit. A canary's corner should have no heating or air-conditioning vent blowing across the bars, no window draft leaking around the frame, and no door swinging open beside the cage through the day. Check what sits nearby: radiators that cycle hot and cold, a fireplace, or a sunny window that turns the cage into a greenhouse by midday all fail this test. One or two walls behind the cage, gentle indirect light, and a clear view of the room pass it comfortably.
The fumes and hazards a canary owner checks first
The kitchen is the first hazard to rule out, because a canary's cage should never share air with regular cooking if another room is available. Overheated nonstick pans, self-cleaning oven cycles, burnt oil smoke, and gas hobs all load the air a small bird breathes. Next, audit the cage's own room for scented candles, wax melts, plug-in fragrances, essential oil diffusers, hairspray and cleaning aerosols, paint, and tobacco or vape smoke. Then look lower-tech: houseplants within beak reach through the bars, exposed cables, and a cat or dog with free access to the cage stand are physical hazards that matter once the air is clean.
Light, song, and getting a full night's rest
A canary's singing and molting follow daylight, so the chosen corner should receive natural light without a shaft of direct sun trapping heat inside the cage. Keep the bird's day and night rhythm steady by dimming the room in the evening and covering the cage if household lights and television run late, since a canary needs a long, dark, uninterrupted night to stay in good condition. Avoid a bedroom if early singing would be a problem, and avoid a hallway entirely, because a canary resting in a corridor gets neither proper quiet nor proper company during the day.
Once the corner passes your checks, write down where the cage stands, which products are banned nearby, and who covers cleaning and seed, then keep that record where helpers can see it, because KinsLe Family Sharing lets the whole household share a canary's profile and care notes so nobody moves the cage beside a scented candle by mistake.