Huddling for Warmth

Beaver in snow, Courtesy US FWS
Beaver in snow
Image Courtesy US FWS

When temperatures dip below freezing and wind hurries on its way, we often find ourselves looking for another warm body to huddle near and share heat. Children snuggle into laps and dogs lean close.

Many animals huddle to stave off the cold. Species that are strong individualists in balmy seasons seek warmth from a group when temperatures drop. Many non-colonial rodents will share a den come winter.

[Kevin Colver recording: Songbirds of the Southwest Canyon Country]

Pygmy nuthatches jam themselves tightly together into tree cavities as do flying squirrels. Through the winter, worker honeybees huddle tightly around a central patch of wax comb where developing larvae are growing. The larvae die if temperatures drop below 83 degrees, so a living blanket of worker bees shivers to generate the heat equivalent to a 40 watt incandescent bulb.

An animal loses heat in direct proportion to its surface area. By huddling together, each animal reduces its exposed surface area. This in turn allows them to reduce their metabolic rate and so conserve energy at a time when food can be scarce or inaccessible.

Nests or dens occupied by numerous individuals can be much warmer than ambient. A snow covered lodge with at least 2 beaver occupants can be as much as 35 degrees warmer than the outside air temperature. A study of taiga voles showed that underground nests containing 5 to 10 residents remained 7 to 12 degrees warmer than the surrounding soil and up to 25 degrees warmer than the air above. Individuals take turns going out to forage so their nest remains toasty.

Living in close proximity does have its problems. Disease and parasites are readily transmitted in tight quarters. Local food competition could potentially lead to hunger or starvation. Predators may more easily discover prey in groups. But for many animals, the advantages of huddling for warmth far outweigh the risks during our chilly winter months.

This is Linda Kervin for Bridgerland Audubon Society.

Photos: Courtesy US FWS

Audio: Courtesy Kevin Colver,,

Text: Linda Kervin, Bridgerland Audubon Society
Additional Reading:

Life in the Cold: An Introduction to Winter Ecology. Peter Marchand. 1991, University Press of New England.

Lives of North American Birds. Kenn Kaufman. 1996, Houghton Mifflin Company.

The Birder’s Handbook. Paul R. Ehrlich, David S. Dobkin and Darryl Wheye. 1988, Simon & Schuster, Inc.

Autumn Leaf Color Change

Fall color in Logan Canyon
Courtesy & Copyright 2007 Linda Kervin

In autumn, the days shorten noticeably and chilly dawns become the norm across most of Utah. Leafy plants now prepare for winter. Their summer of intense metabolic activities gradually give way to winter’s dormancy. Photosynthesis and respiration shut down as nutrients and sugars are withdrawn from leaves, to be shunted to the stem and roots for storage. But how do they anticipate the change in seasons so that they are ready for the rigors of winter?

Photosynthetic plants have a diverse array of pigments that they use to capture energy from most of the spectrum of visible sunlight. Chlorophyll is the most abundant, but its light gathering effectiveness is limited to a narrow band of the light spectrum. Plants employ many additional pigments to capture the energy available from other wavelengths of sunlight. These accessory pigments are brilliantly colored but masked by the sheer abundance of green chlorophyll.

Fall color in Logan Canyon
Courtesy & Copyright 2007 Linda Kervin

One of these pigments, phytochrome, serves as a timekeeper for the plant. When phytochrome absorbs energy in the red band of sunlight, it helps to activate a number of developmental processes in the plant. As the nights lengthen in the fall, there are fewer hours of sunlight to activate the phytochrome and so it transforms to inhibit those same developmental processes.

One result is that chlorophyll is broken down and its components are moved to storage for use in the following spring. Essential nutrients, such as nitrogen and phosphorus, are likewise withdrawn from foliage for later use. With chlorophyll gone, the other colorful leaf pigments are revealed. Now maples, aspens, sumacs and more blaze for a few weeks of riotous glory.

This is Linda Kervin for Bridgerland Audubon Society.


Photos: Courtesy & Copyright Linda Kervin

Text: Linda Kervin and Jim Cane, Bridgerland Audubon Society

Additional Reading:

Chemistry of Autumn Leaf Color, How Fall Colors Work, Chemistry,

Why Do Leaves Change Color in the Fall?, Anne Marie Helmenstine, Ph.D., Chemistry,

“Autumn: a season of change” (2000) by Peter J. Marchand,

Where to see autumn leaves in Utah:

  • U.S. 89, Logan Canyon, Brigham City to Logan, Logan to Bear Lake
  • State Route 39, Monte Christo Summit, east of Huntsville
  • State Route 190, Big Cottonwood Canyon, east of Salt Lake City, including Guardsman Pass
  • State Route 210, Little Cottonwood Canyon, east of Salt Lake City
  • State Route 92, the Mount Timpanogos loop a.k.a. the Alpine loop, north, east of Provo
  • State Route 150, the Mirror Lake road, east of Kamas
  • U.S. 40, Daniels Summit, east of Heber City
  • Vernal, Red Cloud Loop (See
  • Flaming Gorge – Unitas, State Route 191 and State Route 44
  • State Route 132 Payson to Nephi, the Nebo Loop
  • State Route 31, the Wasatch Plateau, east of Fairview
  • State Route 12, over Boulder Mountain, between Torrey and Boulder (likely the most spectacular of all)
  • The La Sal Mountain loop, east of Moab
  • The Abajo Mountain loop, west of Monticello
  • The canyons of the Escalante River, Grand Staircase-Escalante National Monument, southeast of Escalante

List sources:
Aspens and Fall Foliage in Utah, Jeffrey Otis Schmerker, 2001,
Ogden Valley Business Association,

Fall Colors Tour, Utah in the Fall is a blast of color!,

National Forest Fall Color Hotline, 1-800-354-4595,

Pinyon Jays

Pinyon Jay, Tabiona, Utah
Courtesy and Copyright © 2005 Marlene Foard
As found on

Few birds have such a strong association with one plant that the plants name becomes part of the birds name. Sage grouse is one, Acorn Woodpecker another, but the Pinyon Jay is our topic today. Pinyon Jays are usually found in close association with pinyon-juniper forests throughout the Great Basin and the nutritious nuts of the pinyon pine are their preferred food. The blue and grey birds collect and cache pinyon nuts in summer and fall for later consumption. They have an uncanny recovery accuracy and excellent spatial memory, which allows them to rediscover these scattered caches and eat pinyon nuts all year. They do not recover all the stored seeds, however, and therefore aid in the dispersal of pinyon pines.

Pinyon Jays have a complex social organization and are highly gregarious. []

They spend their lives in large flocks of up to 150 or more individuals. Nesting is communal, although rarely are there more than 2 or 3 nests per tree. Breeding season is in late winter. Many birds spend their entire lives in the flock into which they were born.

Pinyon Jay, Gymnorhinus cyanocephalus, Courtesy US FWS, Dave Menke, Photographer
Pinyon Jay
Gymnorhinus cyanocephalus
Courtesy US FWS
Dave Menke, Photographer

Pinyon Jays are not migratory, but they tend to be nomadic; traveling to wherever there is a good crop of pinyon nuts. They will also eat a wide variety of seeds, insects and berries to supplement their diet and can be found in adjoining sagebrush, ponderosa pine forest and riparian habitats. The conservation status of Pinyon Jays is considered vulnerable. Destruction of pinyon-juniper forests for grazing and changes in fire regimes have resulted in loss of habitat. And what is a Pinyon Jay to do without its pinyon nuts?

Thank-you to Kevin Colver for the use of his bird recordings.

This is Linda Kervin for Bridgerland Audubon Society.

Pictures: Courtesy and Copyright © 2005 Marlene Foard, as found on
Also Courtesy US FWS, David Menke, Photographer
Bird Recordings: Kevin Colver
Text: Linda Kervin, Bridgerland Audubon Society

Additional Reading:

Gymnorhinus cyanocephalus (Pinyon Jay), Fire Effects Information, USDA Forest Service,

Avian Cognition Laboratory, Northern Arizona University,

Pinyon Jays, Utah Bird Profiles,,

Snipes Yipes!

Snipe, Heber, UT
Courtesy of and
Copyright © 2008 Kent R. Keller
As found on

The wild goose chase, the nocturnal tipping of cows and the snipe hunt are all good-natured tricks to play on gullible friends. Geese and cows are real, of course, but so is the snipe, a chunky relative of sandpipers. Its name may be the “common snipe”, but during most of the year, snipe encounters in Utah are anything but common. A few times annually, I flush snipe unexpectedly from the margins of a montane beaver pond, a patch of cattails along a suburban creek, or around valley springs and marshes, any wet place that gives the snipe mud that to probe for invertebrates and vegetative cover for camouflage. But come spring, the hunt for snipe is more hopeful, as I can listen for the male’s aerial courtship displays high above wet meadows and marsh margins. You aren’t likely to see him looping about at first, but when he periodically dives, the wind vibrating his outer tail feathers creates this distinctive winnowing sound:

[Audio: Common Snipe courtesy and copyright 2006 Kevin Colver available from “Songbirds of Yellowstone” and]

Common/Wilson’s Snipe
Courtesy of and Copyright
© 2004 Milton G. Moody
As found on

If you hear that sound near dusk or dawn, scan the skies, for you have found the elusive snipe. Wait a bit and he or his mate may perch atop a nearby wooden fencepost, a comical looking bird with its short legs and long delicate bill. A century ago, the snipe hunt was also real; market hunters devastated snipe numbers. Since then, snipe persist wherever their marshes, wet meadows and bogs have not been drained or filled. When next you are out someplace soggy to admire the spectacular plumage of spring ducks, remember to listen for the aerial display of the common snipe.

This is Linda Kervin for Bridgerland Audubon Society.
Pictures: Courtesy and Copyright © 2004 Milton G. Moody and Copyright © 2008 Kent R. Keller, as found on
Also Courtesy Digital Library, US FWS, Photographer W.F. Kubichek
Bird Recordings: Kevin Colver
Text: Linda Kervin, Bridgerland Audubon Society

Additional Reading:

Common Snipe
Courtesy US FWS Digital Library
W.F. Kubichek, Photographer

Wilson’s snipe, Gallinago delicata, Utah Conservation Data Center, Utah Division of Wildlife Services,

Diet composition of wintering Wilson’s Snipe.(SHORT COMMUNICATIONS)(Repo… An article from: The Wilson Journal of Ornithology by Jon T. McCloskey, Jonathan E. Thompson, and Bart M. Ballard, Digital 2009,

Wilon’s Snipe, Utah Bird Profiles,,