Sunday, 14 February 2016

How do birds survive in extreme cold?

This morning at 5AM our thermometer registered -32C, even colder than the predicted low of -28. According to the Farmzone website yesterday's low for Madoc was -38! Who knows if we're in a "balmy" part of the borough or if the temperature had risen from an overnight low of -38 to -32 predawn. Bottom line - it was cold!

We arrived here Saturday around noon. Once we had unpacked and gotten the home fires burning Christopher went out to fill the bird feeders. Within minutes there were chickadees at the platform feeder. They are always the boldest and therefore the first. But shortly after they were joined by sparrows, finches and house finches and later blue jays.  It always takes a little longer for the juvenile finches to gather at the nyjer seed feeder Alex gave us for Christmas a few years ago.
Juvenile finches at the nyjer feeder. At this age both sexes are an olive green.
And other juvenile finches feeding on the spillover from the feeder above
I had gotten new skis and boots and, notwithstanding the temperature of -24C,  I was bound and determined to try them out. I was out for two and a half hours and got frost bite on my left ear lobe. That made me curious how those little birds could survive 24/7 in such brutal temperatures and arctic winds.
Trying the new gear in front of the bird feeder
Well it seems not all of them do. For some breeds about 75% of mature birds survive the winter vs 40% of the younger ones. Older birds are dominant socially and younger birds keep their distance from their belligerent elders. The safest and therefore preferred place to eat is the top of the trees - safest from  predators. The older birds get first dibs on this spot and the younger birds are forced to settle into the lower branches.

Simply put birds congregate in groups, eat - fatty foods if possible, fluff up their feathers at rest and hope for a cosy small cavity in which to overnight.

Notwithstanding selfish seniors, it is still true that birds of a feather really do flock together.
Generally there is safety in numbers - more eyes to be on the lookout for predators and better chances of finding the richest food sources. For wild birds eating at feeders the fattiest foods are best; black sunflower seeds, suet, peanuts. Even though squirrels are not predators birds give them a wide berth. When a red squirrel parks itself at our feeder some birds keep a vigilant eye from the safety of a nearby tree while others take the chance and eat the spilled seed on the ground below the feeder.
The red squirrel eyes the feeder from a nearby willow
Once the squirrel is nestled into the feeder the bolder birds gather below to eat spilled seed

Spots of yellow indicate an oriole and finch eyeing the feeder wistfully 
Like us, a big meal slows birds down making them more vulnerable to predators. If they've gotten their fill they take a rest and puff up their down feathers which help trap warm air in air pockets next to their bodies. Despite their misleading name, Downy (and all) woodpeckers don't have down feathers.
Finches at rest all puffed up while they "feather fluff"

Downy woodpecker at the suet feeder
Birds are also extremely susceptible to small changes in wind so they tend to congregate on the side of the tree away from the wind. If that side is also in the sun so much the better.
A blue jay preparing for a landing
Blue Jays also sample the suet while an oriole looks on

And finally, a roosting cavity just slightly larger than themselves helps the bird warm the surrounding air overnight. Other birds crowd together in a roosting cavity to share body heat. And others still can enter into a torpor-like state by lowering their metabolism to conserve energy and require less heat.

From year to year we have some loyal visitors like the mourning doves, chickadees and juncoes. Other birds are more discriminating I guess - trying us out but never to return for a second visit. This is the case with orioles - stunning citrus yellow birds bigger and brighter than the yellow and olive juvenile finches.
Orioles gather to eat seeds on the ground on Jan. 1, 2013
Birds also benefit from seed heads on perennials and homemade goodies like peanut butter pine cones. While this winter hasn't had the sustained cold and heavy snow of the last two years this weekend's deep freeze is only beaten by the record low set in 1899. Whatever the weather, birds can use all the help we can give them. And in return they reward us with colour and industrious activity in what can seem otherwise a monotone and lifeless winter landscape.

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