Tuesday, April 17, 2012

Birds and Weather

We've heard a lot of concerns about weather from nest watchers.  Following the nicest March anyone in the American Midwest can remember, we've had tornado outbreaks, high winds, damaging storms, large fires, and snow. The Decorah Bald eagle nest has been tossed around by wind, the Fort St. Vrain eaglets died of exposure following a spring storm, and the Dairyland Power Genoa cam was damaged by lightning. We get asked daily if we can't do something about the weather: shore up nests, build roofs, and even take young birds from their nests. The short answer: No. I wrote about intervention in an earlier post. We intervene in the case of obvious, acute danger, but weather is a chronic condition that all of us have to live with.

High winds, severe storms, and fire are nothing new. If animals couldn't survive them, they wouldn't be here. The birds we watch are well prepared for the weather challenges they face.
  • It's Cold and Wet! Feathers are wonderful insulators and adult Bald eagles have roughly 7,000 of them. Light and fluffy down feathers trap air, while flight feathers hook together like a zipper, forming a continuous 'vane'. Preening releases an oil that coats the outer layer of feathers, which further protects adult birds from moisture: the outer feathers may get wet, but the bird's body does not. We've watched the adult eagles shake off rain and sleep under a blanket of snow. They are well prepared for cold, wet weather.

    As of this post, all of the Decorah eaglets have their second down. Unlike the first fluffy white down, the 'wooly' second down has insulative properties. Mom and Dad will still protect the eaglets from rain and snow, but they are able to thermoregulate now.
  • It's Hot! We've had a lot of questions about panting this spring. Like dogs, eagles don't have sweat glands. They control heat by panting, radiation through their unfeathered legs and feet, and perching in the shade. March was unusually warm and the cottonwood doesn't leaf out until April, so the eagles spent a lot of time in direct sunlight. We also got to see a little more of the eaglets than we usually do: many cam watchers commented on how lively, naughty, and busy this year's brood has been. The dry, hot weather means that the eaglets spend more time exploring the nest than huddled under Mom or Dad, and everyone spends more time panting.
  • It's Windy! Adults and young hunker down against high winds and storms. Some of their behavior appears instinctive and some is learned. The first year Mom nested here, she turned tail to the wind and was blown out, nearly taking a young eaglet with her. That hasn't happened since. The adults minimize their profiles during high winds, keeping wings tucked in, tails low, and young birds protected. Young birds curtail nest exploration and play, sheltering under Mom or Dad until the wind dies down.  When the adults do get pushed around by sudden wind gusts, they don't grab at the eaglets, and the eaglets are not especially aerodynamic at this point.

    We've also heard from watchers concerned that the Decorah Bald eagle nest will fall/has fallen. The nest weighs approximately 1300 pounds, is tightly woven of strong wood, and is wedged securely into the limbs of a cottonwood tree. The tree is healthy, with no large dead limbs, and near a good water source.  Can we say that the nest will never fall? No. But is it likely to fall? Also no. The nest is very secure and the tree is healthy and relatively secluded from wind. If the nest or tree did go down, we'd be on site as quickly as we could.
In short, we can't do anything about the weather. Fortunately, the birds we watch are equipped to survive it in all but the direst cases. The Decorah nest in particular benefits from an ample food supply, experienced parents, and a relatively sheltered location. Last year, we watched them respond to cold weather and late snowstorms. This year, we've watched them respond to warmer, windier conditions: they've spent more time off the eggs and young babies, and their 'hunker down' time has been more likely to be a response to wind than rain or cold weather.

Here are a few videos that show the Decorah eagles under various weather conditions:
Things that helped me write and learn about this topic:
If you would like to learn more about how animals survive cold weather, I highly recommend Winter World: The Ingenuity of Animal Survival by Bernd Heinrich. If you would like to know more about animals in summer, I highly recommend Summer World: A Season of Bounty, also by Bernd Heinrich.

30 comments:

nejeanie said...

Excellent information, thank you so much.

nejeanie said...

Excellent information, thank you so much.

nejeanie said...

Excellent information, thank you so much.

nejeanie said...

I didn't intend to repeat my comment 3 times:) Guess I got my point across:)

deegsnana said...

Amy, your dedication is admirable. You are doing an incredible job! Thank you very much...

deckercn said...

Thank you, Amy. You're remarkable!

Denise said...

Thank you. We are a collective group of grandmoms & granddads who worry about our wee ones, & it's good to have someone come along & bring our worried minds back down to the reality that our grandkid's parents know what they're doing. Or something like that! lol I know the other night during the storm & then the subsequent intruder alert there was no way I was going to sleep until I felt calm enough that the family was safe & sound - & I knew my fellow cam watchers were in the same boat as me. I only wish I could've talked to them. Thanks again!

Martha said...

I have been following the Decorah eagles almost from the beginning. I have spent more time glued to my computer than on anything ever! I have tried to make as many othere aware of this phenomonal opportunity. It is like an on-site classroom. Thank you and all are involved in this! I have loved every minute of it and learned so much too!!!

Jacque said...

I am new this year and you have just answered so many questions and CONCERNS. I thank you so VERY VERY much. cheers

Sharon said...

Thank you so very much for this invaluable info. Watching this eagle family and learning about them is a gift to all of us. I love it. Thanks for sharing.

Nancy said...

As always, informative and sensitive. Thank you so much for ALL you do - for the EEEEEEs and for those of us who care about them. (I wish the wind would die down a bit tho.....)

Karen Stokes said...

The June 15 2011 windstorm video really opened my eyes to how wise the birds are when it comes to survival in the elements. The eaglets (big!) are playing when a huge wind comes up. The kids hunker down, Mom swings in and crouches in front of the eaglets. All of them have their beaks to the wind, and look safe, smart and secure in the midst of the noise and movement of the wind and nest. After seeing that, I knew they'd be OK.

boby j. said...

I am a grandma too, and am so relieved to know there is back up to protect the babies.

kat Gavinski said...

Best Reality show ever!! We have thoroughly enjoyed the show thus far! Thank you all.

Penny said...

Thanks Amy.

Winona Musgrove said...

thanks so much for your daily update. So interesting.

Unknown said...

Amy, Thanks for your great writing! And so informative. For good views of how the nest is anchored in that multi-trunk fork, they should look at the 2009 cam installation slides; they really show why it doesn't blow down in the winds we've had!

Tia said...

First I would like to say how grateful I am for the cam and for the information that has been provided. I've been learning so much.

This is the first year I've watched cams of any birds so have been absolutely fascinated by this brood. My viewing started just before the second egg hatched, and I have had my computer on most of my waking hours since so I can check in periodically.

I love that there are so many of us experiencing similar emotions and that I'm not the only granny keeping an eye on the wee ones and their very skilled parents.

Mary Jo said...

Wonderful explanations and information, Amy. Very interesting.

sdrose24 said...

Thank you very much Amy, for this continuing educational experience.
Everyday, I learn more about these amazing eagles. This is the best
outdoor classroom.

kittenface said...

Amy do you know about the eggs and parents at Genoa? Please and Thank you

TD Dant said...

Fabulous information, thanks. You report and the Grace of God intervens. Thank goodness we do not need to. God and Mother Nature work so well together.

E Cox said...

I am a second year eagleholic!! I have told my friends to tune in and I am more addicted this year because I realize the time we have with this incredible family will be over before we are ready to say farewell. I am grateful to the staff and all of the volunteers and can't say thank you enough. This is truly a soul touching experience and a witness to the wonders of creation. Bless you RRP for your dedication

E Cox said...

I am a second year eagleholic!! I have told my friends to tune in and I am more addicted this year because I realize the time we have with this incredible family will be over before we are ready to say farewell. I am grateful to the staff and all of the volunteers and can't say thank you enough. This is truly a soul touching experience and a witness to the wonders of creation. Bless you RRP for your dedication

E Cox said...

I am a second year eagleholic!! I have told my friends to tune in and I am more addicted this year because I realize the time we have with this incredible family will be over before we are ready to say farewell. I am grateful to the staff and all of the volunteers and can't say thank you enough. This is truly a soul touching experience and a witness to the wonders of creation. Bless you RRP for your dedication

icy22 said...

This is my first year and I have become an eagleholic along with many of my friends. Your articles are very informative and help us "newbies" not to get as anxious as we would without your guidance. But I did nearly fall off my chair the other night when the owl was prowling around. Thanks to everyone who are on this dedicated team for educating us in the "way of the eagle". This has been a life changing experience and I feel privileged to be such a small part of it.

Sparky_Bill said...

Amy you wrote: "The first year Mom nested here, she turned tail to the wind and was blown out, nearly taking a young eaglet with her. That hasn't happened since. "

Well this is my first year and I have seen her put her tail to the wind and get flipped over twice. Not out of the nest but she sure was shocked.

edramo said...

Eagle shares brunch with vultures.. the picture reveals our national symbol as he is - not always the romantic hunter, soaring high and snatching fish from blue waters. He is also a carrion eater, picking lunch from rotting carcasses. That may be why Ben Franklin preferred the wild turkey for our national emblem. http://weblogs.marylandweather.com/2009/08/eagle_shares_dinner_with_vultu.html

jennyf said...

Montreal, June 6/2014
Are the young ones being fed?

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