Friday, January 5, 2018

How birds suvive harsh Canadian winters

As the temperatures in the area in which I live in southern Manitoba dips towards minus 40 Centigrade I often wonder how birds survive the winter here.

Migration
Some birds, just as some Manitobans, simply travel south for the winter. Humans who do this are often called "snow birds" and they often travel to areas such as Texas, Arizona, Florida, or even parts of Mexico. The premier of Manitoba has a property in Costa Rica.
Hummingbirds are among the first to leave in the fall and the last to come back in the spring. Often they come before the last frost or do not leave before the first frost. In both cases they can die from the cold. Hummingbird feeders should be brought in before the first frosts so that hummingbirds will not linger when they should be on their way south.
Geese and ducks also avoid the winter by migrating south and then returning in the spring.
Robins, warblers, gulls, red-winged blackbirds and many other birds also simply avoid the winter by migrating to warmer climes.
Juncos come from the north and stay around in the fall until there is quite a bit of snow or its gets quite cool and then travel further south.
Some birds consider southern Manitoba the south
While crows migrate south, ravens migrate from the north to spend the winters here. Unlike the crows here in the summer they do not come to eat the cat food I put out for stray cats. I see them in fields in the country side.
Arctic red polls also come south for the winter. I saw a number of red polls at my feeder the last few days. They are quite fat, and that is needed to keep them warm. It is possible that they are common red polls as I am no expert in identifying them.
Many birds simply stay all winter
Magpies come to my feeder all winter, but to eat cat food not seeds, even though their relatives the crows go south. Chickadees also visit the feeder all winter. The common house sparrow also is here all year and often visits the feeder. Nuthatches also stay all winter as do several woodpeckers. Jays also are common throughout the winter.
I have appended a video showing birds that stay over winter in Saskatchewan the next province to the west of Manitoba.
Many birds come back in the spring but simply travel on further north to nest, such as many geese, and juncos.
How birds survive the cold temperatures
Naturalist Brian Keating described for the Canadian Broadcasting Corporation (CBC) how some birds manage to cope with temperatures far below freezing.
Chickadees
Chickadees eat as many fatty foods as they can such as sunflower seeds. I use sunflower seeds in my feeder and that seems to attract them. Keating says that they will huddle together in a winter roost for the night, keeping each other warm.
Keating said: "On the coldest nights when it gets really frosty they enter a nightly hypothermia. Their body core temperature drops and they tolerate it by allowing themselves to chill down."
Keating said that on very cold nights with temperatures in the minus thirties, some birds will even shelter underneath the snow.
Chickadees apparently are better able to recall where they stash foods when it gets colder and also better at tracking down hibernating grubs.
Myrna Pearman , a naturalist from Red Deer Alberta notes that the hippocampus, the part of the brain responsible for memory and spatial organization expands by 30 percent each fall.
Waterfowl
Often geese and ducks migrate too late to avoid freezing conditions. They have a built-in feature to keep their feet from freezing to ice as they land on frozen lakes and ponds.
Keating said: "Hot arterial blood wraps the venous (returning) blood with smaller, branched capillaries just like a glove, allowing for that valuable heat to efficiently warm the incoming blood from the legs and feet. That way they can save that valuable heat energy and keep their core warm."
Arctic Redpoll
The Arctic redpoll is partially migratory in that it tends to move south in November and travel back north again in March and April.
The Arctic redpolls can survive up to 20 hours without access to food even if temperatures drop as low as minus 54 Celsius according to Keating.
The birds have specially designed esophageal pouches that enable the birds to hold on to seeds, while slowly digesting them and enabling them to keep their body temperatures at about 40 degrees C. Keating said: "Their internal temperature can be 73 degrees warmer than the surrounding air, with the two extremes being separated by less than a half a centimetre layer of feathers."
Humans survive by hibernating inside their warm dwellings and when going outside making sure to dress for the cold. Fortunately, modern vehicles usually have heaters that keep us toasty when we have to travel through the cold.
For many, winter is a time for enjoying the outdoors with skiing, skating, snow-shoeing, and snowmobiling. There are absolutely no pesky mosquitoes or other annoying insects to bother you.


 Previously published in Digital Journal

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