Great Blue Heron at Good Harbor Beach ~ Click to view larger
There are several theories as to why birds, especially large wading birds such as herons and flamingoes, stand on one leg, or “unipedal resting” as scientist like to refer to the trait. The seemingly most convincing and best-proved theory is that birds stand on one leg to conserve body heat. It is shown that birds stand on one leg more often when wading, which again points to the thermoregulation hypothesis because water draws away more body heat.
Great Blue Heron (Ardea herodias)
Standing on one leg is not necessarily a sleeping and resting habit. I have filmed Great Blue Herons and Snowy Egrets meticulously preening while standing on one leg. The characteristic is not limited to large wading birds; species with shorter legs, including ducks and swans, also stand on one leg. Another popular theory suggests that wading birds stand on one leg to look less suspicious to aquatic prey.
Center of gravity and line of gravity
To read more about avian sensory physiology, visit the website of Professor Dr. Reinhold Necker. Additional images courtesy Professor Necker’s website.
Thanks for the info Kim, I always wondered about that. Even our parakeets do the one leg thing. I always thought they were resting.
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Interesting to know parakeets do it too, Fred. I have a photo with an egret standing on one leg and will try to locate as well.
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You hit the bulls eye here Kim!! – http://askanaturalist.com/why-don%E2%80%99t-ducks%E2%80%99-feet-freeze/
Very smart birds and when one foot get’s cold move it up under the feathers and place the warm one down 🙂
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Thanks Dave for the link. This link at wiki provides additional information on rete mirabile: http://en.wikipedia.org/wiki/Rete_mirabile
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Thank you for sharing this one also!
Dave:-)
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My brother Peter who has a PhD in Ornithology says it is usually done to conserve heat. Great photos!
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Thanks you Anna.
Seems logical doesn’t it. Where does your brother live? Curious because I have lots of recent photos of atypical birds and would love to confirm their id.
Happy New Year to you and James and Yanni (sp?) and your daughter in NYC!
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Happy New Year to you too! My brother lives in western MA and teaches at a Umass Amherst – he loves to come here to go birding because we have so many species here. I’m sure he’d be happy to look at the photos.
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Thank you Anna–I’d love to get his email address and will email you re.
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I asked Rubber Duck why a Heron stands on one leg.
RD: “Duh, because it would fall over if it lifted the other one!”
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Very funny Paul! Happy New Year to you and your family.
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My family and I just saw a heron standing on one leg yesterday on my father’s boat hoist on Tamarac Island (Stokes Bay-right across from Lion’s Head).
We all thought that his other leg was injured.
Now we know otherwise.
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