Auxiliary HeatingBecause many finches--especially newly imported birds, sick birds, breeding birds, and birds from hot or temperate regions--cannot tolerate very cold temperatures (below approximately 68° F (20° C) for breeding birds and 50° F (10° C) for delicate species from hot climates), they must be offered protection from the cold. Wintering birds indoors is recommended in extreme climates where temperatures drop significantly below what the birds are accustomed to, or where the weather is unusually harsh. Healthy, acclimatized* birds may be housed outdoors in a more mild winter setting if an insulated, heated area is accessible to them. For large enclosures, this is best achieved by building an insulated shed or shelter adjacent to the aviary that has a small entrance hole for the birds. Food, water, lighting, and perching should be available inside of the shelter. For smaller enclosures that do not have a shelter, the aviary itself must be insulated from the wind and, if applicable, snow and ice. Covering a significant portion of the aviary with a wind breaking material (such as clear, thick plastic sheeting) will help to achieve this. Within the insulated area (shelter or otherwise), electric heat panels and/or lamps may be installed to provide auxiliary heating. Lamps may also be installed above the unsheltered portion of the aviary to warm birds that choose to venture outside.
The lamps or panels should be suspended outside of the birds' reach, but near perches so that the birds can move closer to the heat source if they need to. Always make sure perching is available away from the heat source so that the birds can retreat if they become too warm. Of course, be sure to watch your birds for tell-tale signs of temperature-related discomfort (cold birds will often remain fluffed up for extended periods of time, and overheated birds will hold their wings away from their bodies and pant) and make adjustments accordingly. As always, use your best judgment. Insulated shelters may make use of thermostats to help regulate heating.
The lamps and panels themselves are not the red "heat lamp" variety that is available at many pet stores (usually advertised for reptiles). Instead they are composed of a ceramic heating element that produces infrared heat and no visible light (the lamp has a ceramic bulb inserted into an appropriate reflector or lamp holder that is designed to hold ceramic bulbs of a given wattage, and the panel has a ceramic heating element ideally shielded by a plastic cover that can be wiped down for easy cleaning). These heat sources do not warm the air around the birds the way central air heating units do; to the contrary, the infrared radiation they emit warms surfaces, including the birds' bodies. If you stand near a functioning ceramic heating unit, your skin will feel warm while the air around you is still chilly. Higher wattages produce more heat, so the temperature can be controlled by varying the wattage of the unit and the distance between the unit and perches. For outdoor applications (not within an insulated shelter), 250 Watt bulbs are probably the best option. For inside an insulated shelter, lower wattages may be more desirable. The elements will burn out over time, so check periodically to make sure they are still functioning. Panels (see picture on right) are different from lamps as they are thin, rectangular units that can be hung like a picture frame on a wall, and are better for use where space is limited. Brand names for ceramic lamps include Pearlco, and for heat panels include Avitemp; both of these items can be found online.
*Please note that before attempting to house any finch outdoors in a cool climate, the bird must be allowed time to slowly adjust to the change in temperature. This is referred to as "acclimatizing" the animal, and should begin several months before winter temperatures set in.5 Place the bird outdoors while the weather is still mild and allow it to live outdoors during the months prior to winter so that as the days slowly get cooler, the bird becomes accustomed to it. If temperatures fluctuate radically above or below what the bird is accustomed to, bring it indoors or provide it with some other suitable shelter.