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How Birds Keep Warm in the Winter
December 09, 2013

As time goes by, we tend to forget about important dates in history.

This past Saturday (December 7) marks the day that went down in Infamy.

A time in history that did indeed "Awaken a Sleeping Giant".

This past week was a week of appointments.

Or so it seemed that way.

Dentist, doctor, and vet.

The man physical went okay.

My cholesterol is still a bit high at 228.

Doctor put me on Lipitor.

Everything else was good, including blood pressure and PSA.

The Vet said Bobo is doing better (open wounds have healed), but wanted to put a hood and new collar on him.

Poor little guy, Karen had me take the hood off within 2 hours (the collar remains), as she felt Bobo was suffering.

Just as he and Bebe were getting along, we start all over again.

Tuesday evening, Yolanda and I helped decorate church while Karen enjoyed some alone time.

Another week of weather extremes.

On Monday, I broke out the lawn mower one last time to mulch up leaves from my yard and three of my neighbors.

All the beds now have a nice layer of mulched leaves.

As most of North America knows, we are in a deep freeze now.

With the extreme cold temperatures, feeding birds becomes a bit more important.

It also becomes vital to care for your fur kids and farm animals.

You still have time to get your Christmas traditions to me.

Simply reply this letter back to me along with:

Your First Name (last is optional)

Your city or general location.

And state or Province.

With the cold snap, it is a good time to share with you how birds keep warm in the cold weather.

I wrote on this a few years ago, but it is time for a refresher course.


Now here are some important ways that "Nature" helps birds to stay warm during the cold winter.

Winter poses several challenges for our birds as well, especially when the temperatures dip and dip some more.

We don't often think about or wonder how our birds survive the colds nights, we just know they do or at least we hope they do.

Even those moments in the deep South, Desert regions or the Pacific coast where a cold snap or several inches or feet of snow fall, can effect a bird population.

Winter brings extreme cold temperature, strong winds, driving snow and rain.

Nights seem to last forever.

16 hours of darkness and in more northern locations, darkness is even longer.

That doesn't leave a whole lot of time to forage and feed.

Yet, many birds must at least triple their normal intake to survive and do it in half the time.

Each year we lose some of our feathered friends to the rigors of winter.

It's how "Nature" works.

Survival of the fittest.

Passing on the strongest genes.

Birds have many adaptations to survive the extremes of winter.

Some birds migrate.

Some adjust their diet habits.

Birds such as chickadees and American goldfinches add feathers in preparation for winter.

Yes, the typical chickadee or goldfinch is covered with about 1,000 feathers during the summer.

By the time winter arrives, they have doubled that count to more than 2,000 feathers.

For a small bird, that can be some serious added bulk and weight.

During cold, windy or just a plain nasty day, birds will fluff up their feathers.

By doing this, they create dead air pockets, much like insulation or a double pain window.

This reduces the heat loss by up to 30%.

Extra feathers and fluffing isn't enough to make it through a cold winter day yet alone the cold, long dark nights.

If you've been with me any length of time, you have read about blood circulation and bird legs.

Birds have a unique circulatory system in there legs to help them cope with cold temperatures.

Pay attention to this now.

Warm arterial blood from the birds interior, which is on its way to the bird's legs and feet, passes through a network of small passages that runs alongside the cold returning blood veins from the feet.

The network of vessels acts like a radiator and exchanges the heat from the out-going warm arterial blood to the cold venous blood.

By warming up the old blood, no heat is lost and the feet receive a constant supply of life sustaining blood.

This is also why water fowl can swim in near freezing water and not get cold.

In the summer, this works as a bit of an air conditioner.

A Side Note:

Because the blood doesn't warm up a bird's feet and because of the scales (no skin, no sweat) birds don't freeze to metal poles or birdbaths.

I digress.

Fat is another important winter weather survival adaption.

Fat acts as an insulator in addition to an energy reserve.

During the day, birds eat to build up fat reserves.

On average, a bird can put on up to 15% to 20% of body weight in fat before it becomes to heavy to fly.

Now remember, days are shorter and cold.

Birds have to eat enough to survive the day as well as replenish the fat reserves.

The smaller he bird, the higher the metabolism (more energy burned).

Birds don't have brown fat, the kind we have.

Instead they have white fat.

White fat is a high-energy fuel used to power the bird's warming process.


Thermogenesis is a fancy name for shivering.

You can't really see it, but all birds shiver in the cold of winter.

From the largest of birds like eagles and water fowl to the smallest of birds like hummingbirds.

They all shiver to maintain their core body temperature at about 106 to 109 degrees, depending on the species.

That is an amazing high temperature compared to the surrounding air temperatures.

This past week in some locations, that is more than a 150 degree difference.


Shivering produces heat five times their normal basel rate and can maintain a normal body temperature for six to eight hours at temperatures dropping to minus 70 degrees Fahrenheit.

That is quite a drop in body temperature, considering most birds normal temperature run about eight-ten degrees warmer than humans.

Without shivering the bird's body temperature would quickly drop and the bird would become hypothermic.

I might add this, penguins only shiver if a patch of skin is showing, or there is some feather damage. Penguins are a different sort.

At night, birds such as the little chickadee take shivering, or lack of, one step further.

To conserve heat and energy, chickadees can lower their body temperature by interrupting their shivering.

These periods of inactivity allow the bird's body temperature to slowly cool, until it drops an additional 10 or 12 degrees.

At this point, the bird enters a state of unconsciousness called torpor.

Respiration and heart rate will also drop during this period.


As morning nears, the periods of inactivity decrease until the bird is constantly shivering once again.

The body temperature is back in the normal range and the bird regains consciousness.

The results of this torpid state is an energy savings of up to 20% during a typical winter night. (much like you and me turning the thermostat down before we go to bed).

Conserving energy is very important when you consider how little fat a bird can store.

Based on a daily increase of body fat of 15% a typical chickadee has about 16 to 24 hours of fat or energy reserves to carry it through a winter night.

That my friend is why it is imperative that a bird gets out early in the morning and stays out late to find food regardless of the weather.

If it doesn't replenish its fat reserves every day, the bird will not have enough energy to make it through the next night and will die.

There was a time when the natural world provided food for most wildlife.

With the constant shrinking of habitat, winter protection and food supplies continue to shrink.

You can increase the odds for birds and some mammals by simply filling your feeders with their favorite food and offering suet.

Fresh water is important as well.

When birds are required to eat icy cold snow, it takes valuable energy to warm that snow as it passes through.

Next time you trudge out into the cold or even the warmth to fill your feeders, think of this...............

God has provided birds with some wonderful tools to survive.

Whether it is migration, blood circulation, change of diet, added feathers, or shivering.

Most birds will survive the elements.

Birds are truly a wonder for us to enjoy.

In one hand, it is unfortunate that many birds now need our help to survive.

In the other hand, look at the education and joy we get out of caring and feeding our birds.

Not to mention that feel good all over feeling we get.

Well, it's time to fly for now.

Before I go, here is your positive thought for the week.

God Bless.

Laughter is the sun that drives winter from the human face.

Victor Hugo

Indeed, laughter and a glad heart is good medicine.

For the spirit.

For the heart.

For the whole person.

A merry heart does good [like] a medicine:
but a broken spirit dries the bones.

Proverbs 17: 22

"Treat the earth well:

It was not given to you by your parents,

It was loaned to you by your children.

We do not inherit the Earth from our

Ancestors, we borrow it from our Children."

Ancient Indian Proverb

Your friend indeed,

Ron Patterson

PS. If you enjoy these letters, please forward them to friends, family and co-workers.

Better yet, have them sign up so they can receive their own letters.

Gardening For Wildlife.

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