Having studied up considerable on birds over the years I believe COLD per se, does not usually kill birds, certainly not as temperate a species as mourning doves anyway. There are numerous incidents of summer birds even down to the size of hummingbirds surviving long into northern winters as far north as Alaska as long as they had a reliable supply of food.
Feathers are EXCELLENT insulation, I believe the incidence of ice forming overnight on the white-wing doves head being an illustration of that. Ice against the actual skin of the head would AFAIK quickly and fatally chill the bird, OTOH roosting birds are often covered with snow, so little heat escaping through the feathers that no snow melts to wet the bird.
Perhaps you can tell me what killed the dove in what I described earlier, with many, many dove being lethargic, then dead in a 12 hour period where there was a temperature change from the 60's to minus 15?
It happened relatively fast. At dusk all the dove were lethargic and you could walk right up to them, and in the morning they littered the ground. Killed all of them. No exceptions. Dead dove were everywhere in any direction for at least 75-100 miles.
That storm killed lots more than dove too. It killed cattle, and various other livestock and wildlife. A guy took a picture of a fox that was frozen dead, and it was curled up, looked like it was sleeping.
