A Chickadee Never Forgets

Winter storms like the one that’s beset Nova Scotia the past couple of days provide the ultimate test for chickadee memories.  When food supplies become scarce due to snow cover, they must rely on their memories to retrieve food that they hid when supplies were more plentiful.

A chickadee may have up to a hundred bits of food (seed, insect or berry) hidden in nooks and crannies in the forest.  Each piece is stashed in a different place.   Just before the storm peaked yesterday afternoon I noticed a small flock of chickadees coming and going non-stop from a pile of sunflower seeds I had set out for them.  They weren’t eating the seeds but hiding them in the bark of trees and coming back for more.   They had good reason to be working so quickly.  In about 15 minutes, the pile of seeds I had put out was buried under snow.

During winter nights, the body temperature of chickadees drops about ten degrees as they enter a state of torpor, enabling them to survive the cold.  Still, they need to eat during the day.  If a chickadee couldn’t remember the location of its stashes, its chances of survival would be slim.  I wonder if older chickadees are subject to memory loss like humans as they age. 

This morning I shoveled the driveway while listening to a flock of chickadees cheerfully calling out to one another in song.  The little chickadee in the photo below appears to be doing a dance of joy.  Happy as a bird, it’s probably celebrating making it through yet another winter storm.  Perhaps we should do the same 🙂

For more information about chickadees, see my previous post about The Private Lives of Chickadees.

If you’d like to learn how to feed chickadees by hand, see my previous post about How to Handfeed Wild Birds.

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The Benefits of Lichens on Trees

What if there existed something in nature that could gauge air quality?  There is.  Though they have a preference for rough bark, lichens grow on most of the trees here.  Consequently, most of the tree trunks in the woods around my home are a light grey.  This is a good thing, as lichens are bioindicators of high quality air in the environment.  The more three-dimensional the lichens are, the better the air quality.

Lichens are not plants.  They are a mutually beneficial relationship between a fungus and algae.  For more information about this relationship, see my previous post about Lichens.

When it rains, lichens act as a sponge by absorbing as much water as possible.  After the rain stops, they slowly release the water back into the environment.  This process keeps humidity levels in the forest more stable than if the water was simply allowed to fall directly onto the ground.

The three-dimensional properties of lichens also make them ideal places for arthropods to survive.  It’s no wonder then, that birds are especially attracted to tree trunks covered in lichens.  Even chickadees that have access to seed in the winter will consume arthropods for 50% of their diet.

Considering the above benefits, wouldn’t it be helpful to promote lichen growth on trees in the city?

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The Private Lives of Chickadees

Most people think chickadees are cute and in the winter, wonder how such tiny birds manage to survive in the brutal cold.  Yet there is more to the average chickadee than most would assume…

Black-capped Chickadees are frequent visitors to my yard.  Unlike many other birds, chickadees aren’t skittish and will actually allow you to get close to them while they’re eating.  Some have been bold enough to take food out of my hand.  They are dear little creatures, with a musical chorus that regularly enhances the outdoor experience in my neighborhood.

Chickadees have quite an established hierarchy within the flock.  Birds at the top eat first and command the safest feeding spots and sleeping nooks.  An alpha male will inevitably mate with an alpha female leaving the rest of the flock to fight among themselves for next-in-line pairings.  In a well established flock, fights are few, as everyone seems to know their place.  Though most pairs will mate for life, certain females will opt for divorce in an effort to improve their social status.

Chickadees maintain a body temperature of 107 degrees F during the day.  On cold winter nights, this drops about 10 degrees as the chickadee enters a state of torpor that reduces its need for food.  Dominant chickadees in the flock manage to acquire the coziest spots for night roosting, scrunching themselves into tight tree holes, but also under branches where they receive some protection from winds and predators.

Chickadees cache food and an individual’s ability to survive a harsh winter will depend greatly on its ability to recall where caches are located.  Each morsel is hidden in a separate spot and there may be 100 of them hidden in a single day.

If you’d like to attract chickadees to your yard, try offering some black oil sunflower seeds, suet and/or fresh water.  Due to their tame nature, chickadees are one of the easiest wild birds to handfeed.

For tips on handfeeding wild birds see my post on this subject at:

https://flandrumhill.wordpress.com/2008/11/03/how-to-handfeed-wild-birds/

References:

Divorce and Extrapair Mating in Female Black-capped Chickadees http://www.springerlink.com/content/qbmjt2dt9qk71gkd/

Between-year survival and Rank Transitions in Male Black-capped Chickadees http://caliber.ucpress.net/doi/abs/10.1525/auk.2008.07092

Poecile atricapillus  http://www.fs.fed.us/database/feis/animals/bird/poat/all.html

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