The Real Risk for a Finch Is the Panic, Not the Noise
A zebra finch weighs very little and flies first and thinks later. When a firework cracks overhead, the whole flock can erupt off the perches at once, and in complete darkness those tiny birds collide with bars, feeders, and each other. Most fireworks injuries in finches are crash injuries from that blind panic, not the sound itself. So the heart of preparation is different from preparing a parrot: you are not comforting an individual bird, you are arranging the cage and the light so that a startled flock can flutter, see where it is going, and resettle without hurting itself.
Move the Cage Early, With the Flock Inside
Shift the flight cage, finches and all, into the quietest interior room before dusk, rather than catching birds and carrying them in your hands or a box, which is terrifying and risky for a bird this small. Choose a room away from street-facing windows, close the curtains, and shut the door against household pets and party traffic. Set the cage on a stable surface at its usual height rather than on the floor, where vibrations from footsteps and slamming doors feel larger.
Light the Cage for a Startle, Not for Sleep
Total darkness is the trap with finches. Leave a dim night light on in the room, or a small lamp shaded so the cage gets a soft glow; enough for a panicked finch to see perches and bars mid-flight, not enough to keep the flock awake and active all evening. If you use a cover, drape it over the back and top only, leaving the front open to that soft light. Check that perches are firmly fixed and spaced so a bird bursting upward does not hit a hanging toy, and remove anything dangling or loose that could tangle a wing in a scramble. Keep seed, a millet spray, and water in their usual places, and add nothing new on the night.
Let the Flock Settle Itself
When the display starts, the finches will flush at the first loud bangs; that is expected, and it passes. Stay out of the room as much as you reasonably can, because a person looming at the cage adds a second fright to the first. Soft, steady background sound from another room helps blur the bangs without making the finches' own room stimulating. Never open the cage during the display to check on a bird, straighten a perch, or retrieve one that is fluttering; an escaped finch in a dark, noisy house is in far more danger than one inside a cage. Speak quietly if you must enter, move slowly, and leave again.
Checking the Flock Afterwards
Once the noise has fully stopped, look through the bars in good light for the injuries panic causes: a bird on the cage floor unable to fly up, a drooping wing, blood on a perch or feather, or one finch sitting fluffed and apart from the group that does not rejoin it. A small finch that is bleeding, cannot fly, or stays on the floor needs an avian veterinarian promptly, and should be kept warm, dark, and untouched in a small lined box for the journey rather than repeatedly examined. A flock that is feeding, calling, and squabbling over the millet by morning has recovered.
A Plan You Can Reuse Every Celebration
Fireworks come round more than once, and finch keepers get better nights by noting what happened: how the flock reacted to the night light, whether the room was quiet enough, and whether the partial cover helped. Keep those notes with the feeding and health details you already track for the flock. KinsLe's Kimmy, the built-in assistant, can be asked for guidance in the moment on a night like this, and what you learn about your zebra finches stays alongside their profile, ready for the next celebration.