Indoor birds should not be kept in an unheated room during the winter - anything below 8C will make them shiver and could lead to a depressed immune system. In general, if the ambient temperature is comfortable for you, it will be comfortable for your finches.
Birds kept outdoors need to be kept warm in the colder months
If a finch is feeling the cold, he will sit with his feathers fluffed up for long periods (conversely, if too hot he will sit with his wings away from his body and his beak open). Keeping a cover over the cage at night will help retain heat.
Indoors, central heating or storage heaters will solve the problem, especially if you have temperature regulators on each radiator. Make sure the birds’ room is well-sealed, to minimise draughts and temperature plunges. Double-glazing will reduce the risk of an overnight freeze.
An open fire to heat an indoor room isn’t hazardous to finches, (as long as all the smoke is going up the chimney). If this is the only source of heat, however, the room will soon cool down during the night; so, again, make sure the room is kept as cosy as possible.
What Temperature do Canaries and Finches Need?
Canaries and larger finches can survive temperatures as low as -8C in the wild, but these are extremes that should be avoided. All outdoor or bird room finches will need protecting from the winter cold with an aviary heater. Indoors, the temperature should not be allowed to dip below 8C.
Naturally hot or cool air temperatures are not usually a problem for healthy Canaries and pet finches, so any European country is a suitable location. Sudden changes in temperature, however, are bad for the birds. Avoid doorways or other drafty spots, and don’t place the cage next to radiators or air-conditioning units.
You can check for drafts by lighting a candle and holding it still on each side off the cage for a few seconds. If the flame flickers, you have a draft to contend with. Draft excluders or the judicious placing of draft-blocking objects may solve the problem.
If your birds are being kept outdoors in an aviary, there will need to be plenty of shelter from wind and weather, in the form of screens, canopies and indoor areas. See the Aviaries and Bird Rooms section for more details.