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How can redpolls survive our winters?

I was given another bird book for Christmas — actually I was given two, but who’s counting?
Common Redpoll
The redpoll has a unique digestive system that allows it to survive winters.

I was given another bird book for Christmas — actually I was given two, but who’s counting?

One of them is going to come in very handy in the next few weeks.

The Red Deer River Naturalists are having their annual Birding Trivia Night on Jan. 19. 10,001 Titillating Tidbits of Avian Trivia will be very helpful.

There are questions that deal with birds we don’t have around here, of course, but a lot of them are relevant.

And the questions themselves can teach a person something. For instance, “When closing their eyes, are diurnal birds more likely to draw up the lower lid than to lower the upper eyelid?”

The answer is, “yes,” but I hadn’t realized that there was a difference. They also give a qualifier in the answer: “but in nocturnal birds, it is more likely that the upper lid will be lowered.” Fascinating.

How do the green-winged teal nesting in Alaska’s Aleutian Islands differ in appearance from those that breed throughout the remainder of North America?

Again, I hadn’t realized that there was a difference. The answer in the book is “The Aleutian Green-winged Teal is a separate race, and breeding-plumaged drakes closely resemble males of the Eurasian race. Rather than a broad vertical white stripe down the side, the white stripe is horizontal.”

How are redpolls able to survive really cold winters? I would have said that they go south for the winter. Wrong! They do come south but not very far. They come to us. But the answer is, “Redpolls have a high rate of energy intake owing in part to a special storage pouch in the esophagus. This is filled with food just before darkness so as to digest the food overnight. The birds also select high-calorie foods, such as birch seeds.” It really is amazing how birds can adapt.

This winter is a poor one in our area, so far, for redpolls. We had very few of them counted at the Christmas Bird Count.

Redpolls are what are called an “irruptive” species. That means large numbers of them will migrate into an area after the breeding season on certain years. This is dependent upon the food source. So if it’s a good year for the food source up north, the redpolls don’t need to move out. On a bad year, they will starve if they stay so they move out.

All of the above questions came from only two pages in this book.

From those same two pages, I have found out that most hummingbirds bathe, a male ruffed grouse braces himself with his tail when drumming, a domestic Japanese quail can lay 365 eggs a year, female northern harriers migrate before the males do and the sulphur-crested cockatoo in the TV series Beretta was named Fred. Imagine how much I will learn if I read the entire book!

Judy Boyd is a naturalist with the Red Deer River Naturalists.