Excerpt from BIRD TALK Magazine, December 2004 issue, with permission from its publisher, I-5 Publishing.
A strong immune system can help protect a bird from getting sick in extreme cold weather temperatures.
Although hypothermia is still serious, it is not as quickly fatal to birds as heat stroke, according to Larry Nemetz, DVM, an exotics-only veterinarian in California. While a bird can succumb to heat stroke in just 15 or 20 minutes, a bird that suffers from hypothermia will have to become chilled for several days in a row before it starts feeling any negative effects. When it does, exposure to extreme cold is very similar to that of heat stress in that it weakens the bird’s immune system and opens it up to infections. This is especially true if the bird is not eating on good food or is in poor health.
Often, a bird is a carrier or is dormant for a particular disease, Dr. Nemetz said, but then "the cold temperatures weakens the bird’s immune system enough that the virus or bacteria manifests itself and then the bird has a really serious illness. But as long as the bird’s immune system is strong, it keeps the disease at bay.”
Birds that suffer from hypothermia look very similar to sick birds: they fluff out their feathers, they shiver, and they might squat on their perch to cover their feet or they may perch on only one foot while keeping the other tucked up close to their body.
How do you know whether your bird is just chilled or actually sick? "If it’s 80 degrees and your bird is shivering and fluffing out its feathers, it’s probably sick. But if it’s 60 degrees and your bird is doing this, it may just be cold,” Dr. Nemetz said.
Besides hypothermia, birds can also suffer frostbite. This is more often a problem in escaped pet birds rather than outdoor aviary birds (which have probably become adapted to cold temperatures).
Missouri veterinarian, Julie Burge, DVM, has treated a number of indoor pet birds for frostbite after they escaped outdoors in the winter. "In one of these cases the bird lost most of its toes when it sat on a metal surface in freezing temperatures for several hours,” Dr. Burge noted. "An indoor bird that is not acclimated to cold temperatures cannot adjust its circulation adequately to keep enough blood flow to the toes in these circumstances.”
Outdoor birds can also suffer frostbite — if it suddenly falls below freezing and the birds are not used to it and if they do not have adequate shelter to protect themselves.
Want to know about how to keep birds warm in cold weather?
Pet Bird Winter Care Tips
Ideal Temperature Ranges For Parrots