Category: Birds

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Small birds in cold temperatures

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Black-Capped Chickadee, Copyright Stephen Peterson, Photographer
Black-Capped Chickadee
Copyright Stephen Peterson, Photographer

Hi, I’m Holly Strand from Utah State University’s Quinney College of Natural Resources.

There is a biological principle that states that species or populations that live near the poles tend to be bigger than those closer to the equator. Called Bergmann’s rule, this principle seems to work pretty well for some animal groups. Consider the size of polar bears, walruses, or penguins. An explanation behind Bergman’s rule is that large animals have a lower surface-to-volume ratio. Therefore they lose less body heart per unit of body mass. Furthermore, the larger you are, the more fat reserves you can carry around with you. Fat reserves represent potential energy, which is pretty useful to have in severe environments.

Large size could come in handy when dealing with Utah’s cold winter. But what about our little creatures? Like the small birds that forego a winter vacation in Arizona or Central America? Without the advantage of large size, how do they keep from icing over when the temperature drops?

Inactivity conserves energy so these little birds go to bed early and get up late in winter. That’s why your feeder looks so deserted on cold mornings. For a roosting spot, birds choose locations that offer protection from both the elements and from predators. The thick branches near the trunk of a conifer work nicely. And some species will seek out tree cavities or nest boxes. While roosting, birds may huddle together to create additional warmth.

Shivering helps a bird to increase its metabolic rate and generate heat when roosting. The drawback is that shivering requires a lot of calories.
An alternative approach that requires less energy is to simply reduce the core temperature of your body. The diminutive black-capped chickadee is well-known for surviving the cold using this adaptive form of self-induced hypothermia.

Good insulation is critical for survival. Some birds–like juncos and finches– put on extra fat. But all birds have feathers which are great for insulation. You’ve probably seen a bird fluff itself out, looking like a chubby feather ball. The bird does this to trap air next to its body to creating a nice warm down coat.

Bird parts not covered with feathers are more vulnerable to cold. So birds will bury their bills into their plumage and will tuck in their feet underneath.

During the shortened, active daytime hours little birds need to consume as many calories as possible. We can help them most by providing high energy food items such as oil sunflower and suet. For more information on what you can do to help Utah birds survive the winter chill, go to www.wildaboututah.org.

For Wild About Utah, I’m Holly Strand.

Credits:
Image: Courtesy Bridgerland Audubon Society, Copyright Stephen Peterson, Photographer
Text: Holly Strand

Sources & Additional Reading

Cooper, Sheldon J. and James A. Gessaman. 2005. Nocturnal Hypothermia in Seasonally Acclimatized Mountain Chickadees and Juniper Titmice. The Condor 107:151–15 https://www.uwosh.edu/faculty_staff/cooper/articles/Condor%20107%20151-155.pdf

Elkins, Norman. 1983. Weather and Bird Behavior. Calton, England: T& AD Poyser. https://www.amazon.com/Weather-Bird-Behaviour-Norman-Elkins/dp/0856610356

Kress, Steve. 2010. Audubon Guide to Winter Bird-Feeding. Audubon Magazine Published: November-December 2010
https://www.audubonmagazine.org/articles/living/audubon-guide-winter-bird-feeding

Marsh, R. L., and W. R. Dawson. 1989. Avian adjustments to cold. In: Advances in Comparative and Environmental Physiology, vol. 4, edited by L. C. H. Wang. Berlin Heidelberg: Springer‐Verlag, p. 205–253. Citation

Smith, Susan. 1991. The Black-Capped Chickadee: Behavioral Ecology and Natural History. Comstock Publishing
https://www.amazon.com/The-Black-Capped-Chickadee-Behavioral-Comstock/dp/0801497930

Yuhas, Daisy. 2013. How Birds Cope With Cold in Winter. Audubon Magazine Published: 12/12/2013 https://www.audubonmagazine.org/articles/birds/how-birds-cope-cold-winter

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Nature’s Recyclers

Courtesy and copyright Andrea Liberatore, Stokes Nature Center, https://logannature.org/
Fungi Decomposing Fall
Leaves Outside the
Stokes Nature Center
Courtesy & © 2011 Andrea Liberatore
Stokes Nature Center 

Courtesy and copyright Andrea Liberatore, Stokes Nature Center, https://logannature.org/Redworms Eisenia fetida
from Stokes Nature Center’s
vermicomposting system
Courtesy & © 2011 Andrea Liberatore
Stokes Nature Center

On November 15th, our nation celebrates America Recycles Day. While the day itself tends to focus on human recycling activity, I thought we should also give a nod to nature’s recyclers. Worms, maggots, fungi, beetles, and bacteria – it sounds like a list of leftover Halloween horrors. But in reality, we should be more afraid of what our world would look like without these creepy-crawlies, for these are nature’s recyclers. Scientists call these organisms saprophytes, and as important as their role in life is, they are more likely to evoke a shudder than any feeling of gratitude.

What decomposers actually do is break dead things down into smaller and smaller pieces, until all that is left are the basic molecular components that make up all living things such as nitrogen, phosphorous, carbon, and potassium. Once broken down, this material is then free to be taken up again by plants and animals that use them to live and grow. This cycle of nutrients is vital to life on Earth, and our saprophytic friends make it all possible.

While decomposition would occur even without the help of the decomposers, it would take much, much longer. In some landfills, newspapers have been unearthed that are more than 20 years old, and still quite readable. This is because landfills often create anaerobic environments, where oxygen-loving insects, fungi, and bacteria cannot live and therefore cannot aid decomposition. If without decomposers, a newspaper can last 20 years, what would happen to much larger and hardier items such as tree trunks and roadkill? I shudder to think about it.

Did you know that the U.S. throws more than 33 million tons of food waste into landfills each year? This organic material goes to waste there – taking up valuable space and taking longer than normal break down. So this year, celebrate America Recycles Day by employing some of nature’s recyclers in your yard. Consider starting a compost pile where your fall leaves and food scraps can get broken down into nutrient-rich all-natural fertilizer for next year’s garden.

For composting tips and more information about nature’s recyclers, visit Wild About Utah online at www.wildaboututah.org. Thank you to the Rocky Mountain Power Foundation for the research and development of this Wild About Utah topic. For the Stokes Nature Center and Wild About Utah, this is Andrea Liberatore.

For the Stokes Nature Center and Wild About Utah, this is Andrea Liberatore.

Credits:

Photos: Courtesy & © 2011 Andrea Liberatore, https://logannature.org/
Text:    Andrea Liberatore, Stokes Nature Center, logannature.org

Composting Tips & Information:

Farrell-Poe, K. and Koenig, R. (2010) Backyard Composting in Utah. Utah State University Cooperative Extension. https://extension.usu.edu/files/publications/factsheet/HG-Compost-01.pdf

U.S. Environmental Protection Agency: Composting. https://www.epa.gov/epawaste/conserve/rrr/composting/index.htm

Additional Reading:

Fogel, R. (2002) Waste Not, Want Not: Fungi as Decomposers. Utah State University Herbarium. https://utahpests.usu.edu/ipm/ornamental-pest-guide/diseases/wood-decay-fungi

Hoff, M. (2009) Young Naturalists: Nature’s Recyclers. Minnesota Conservation Volunteer Newsletter. July-August 2009. https://files.dnr.state.mn.us/publications/volunteer/young_naturalists/natures_recyclers/natures_recyclers.pdf

U.S. Environmental Protection Agency (2011) Basic Information About Food Waste. https://www.epa.gov/osw/conserve/materials/organics/food/fd-basic.htm

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Bird Gizzards and the Old Grind

Chicken Gizzard
Chicken Gizzard
Copyright 2013 Jim Cane
Chicken GizzardNaturally polished dinosaur gastrolith found near Duschene Utah
Copyright Rick Dunne, Photographer

You may think of “the old grind” as your workweek, but from a dietary perspective, the old grind links your holiday turkey with dinosaurs. Before making gravy this Thanksgiving, find the densely muscular organ amid your turkey’s giblets. This is the turkey’s gizzard which preceded the living bird’s intestine. In its tough-walled gizzard, a bird mechanically breaks down hard or tough foodstuffs like we mammals use our molars. Reducing chunks to crumbs gives digestive enzymes the large surface areas needed to efficiently digest food.

Being toothless, birds must swallow most nuts, seeds, bugs and mollusks whole. In the gizzard, these items are churned, crushed and ground up, aided by ingested sand, grit or small stones called “gastroliths”. A turkey’s gizzard squeezes with twice the force of our own jaws. At 400 pounds per square inch, this force shatters acorns and even hickory nuts. The gizzard works like the ball mills used in mining, wherein heavy rotating iron drums loaded with steel balls pulverize rock ore. Like a gem tumbler, though, the gizzard eventually smooths and polishes its gastroliths. Having thus lost their utility, these stony gastroliths are regurgitated.

Gastroliths did not originate with birds, Continue reading “Bird Gizzards and the Old Grind”

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Shrikes

Loggerhead Shrike
Loggerhead Shrike
Lanius ludovicianus
Copyright 2013 Linda Kervin

Northern Shrike Courtesy US FWS, Dave Menke, Photographer Northern Shrike
Lanius borealis
Courtesy US FWS, Dave Menke, Photographer

The name songbird conjures up an image of a colorful singing warbler. But one family of songbirds, the shrikes, are fierce little predators. No bigger than a robin, shrikes mainly eat insects, especially grasshoppers and crickets, but they also prey on rodents, small birds, lizards, snakes and frogs.

Utah has 2 species of Shrike: the Loggerhead which resides here year round and the Northern which breeds in tundra and visits Utah in the winter. Shrikes prefer semi-open country that has some trees, shrubs or fenceposts where they perch to watch for prey and then swoop to kill with their thick hooked bill.

Shrikes are sometimes called butcher birds Continue reading “Shrikes”