Category: Vertebrates

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Rattlesnakes

Great Basin Rattlesnake
Courtesy & Copyright 2009
Holly Strand
Hi, I’m Holly Strand from Stokes Nature Center in beautiful Logan Canyon.

Its rattlesnake season in Utah, for the warm weather draws them out of their dens. We have 5 species plus 2 subspecies of rattlesnake in the state. The Great basin rattlesnake is the most widespread, living all across Western Utah at elevations up to 9000 feet. This is the fellow you see around Logan. Another subspecies of western rattler–the midget faded rattlesnake –is dominant in the eastern part of the state. The Hopi rattlesnake and the greenish colored prairie rattlesnake are found in southwestern Utah. And the Mojave rattlesnake, speckled rattlesnake, and sidewinder are found only in the extreme southwest corner of Utah.

The rattle itself is a unique biological feature. It’s a loose, but interlocking series of nested segments—actually modified scales– at the end of the tail. When vibrated, the rattle produces a hissing sound. Kevin Colver– an expert in natural sound recordings –provided this clip of a Mojave rattlesnake. Sound from Westernsoundscape.org Hmm. wouldn’t that make a great ringtone?

Aggression and venom in rattlesnakes vary by both species type and by individual. The western diamondback rattlesnake is the archetypal large, aggressive and very dangerous species, responsible for the majority of human fatalities. But its northern range limit is south of the Utah border. However, the Mojave rattler found in southeastern Utah is extremely toxic and excitable. Its venom attacks both the nervous system and circulatory system.

Luckily, rattlesnakes aren’t out to get us—mainly they just want to be left alone. You’ll be fine if you stay aware of what might be lurking in or around rocks. And don’t walk barefoot or in open-toed shoes in their habitat. Also, use a flashlight after dark –most rattlesnakes are active at night too!

Thanks to the Marie Eccles Caine Foundation—the Russell family for supporting Stokes Nature Center programs. And to Kevin Colver for the sound of the rattlesnake. Additional nature sound recordings can be found at 7loons.com and westernsoundscape.org

For Wild About Utah and Stokes Nature Center, I’m Holly Strand.

Credits:

Theme: Courtesy & Copyright Don Anderson Leaping Lulu
Audio:     Courtesy & Copyright 2006 Kevin Colver, https://wildstore.wildsanctuary.com/collections/special-collections & Jeff Rice, https://collections.lib.utah.edu/search?q=rattlesnake&facet_setname_s=uu_wss [Updated January 2024]
Jeff Rice Bio: Ecosystem Sound [Updated February 2026]
Images:     Courtesy & Copyright 2009 Holly Strand
Text:     Holly Strand, Stokes Nature Center
Voice: Holly Strand, Stokes Nature Center

Sources & Additional Reading:

Klauber, Laurence M. 1982. Rattlesnakes. Their Habits, Life Histories, and Influence on Mankind. Berkeley: University of California Press, https://www.amazon.com/Rattlesnakes-Habits-Histories-Influence-Mankind/dp/0520210565 (1997 Version)

Vipers, Species, Utah Division of Wildlife Resources, Utah Division of Natural Resources, https://fieldguide.wildlife.utah.gov/?family=viperidae [Updated January 2024]

Tips to stay safe around rattlesnakes, Utah Division of Wildlife Resources, Utah Department of Natural Resources, https://wildlife.utah.gov/news/utah-wildlife-news/943-rattlesnakes-safety-tips.html [Updated January 2024]

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Nighthawks Go Boom

Common Nighthawk courtesy US FWS, Dr Thomas G. Barnes Photographer

Birds gotta fly, and for that they have wings. But nature is a tinkerer, adding new functions to old adaptations, and so it can be with feathers.

Males of some birds make sounds during aerial courtship displays, sounds that do not originate in their throats. When these suitors periodically dive during flight, their modified wing or tail feathers vibrate like the reed of a saxophone, creating a hum that appeals to potential mates. In an earlier program, you heard the winnowing sounds of diving male snipe, and if you have a hummingbird feeder at home, you have been hearing a wing trill from insistent male broad-tailed hummingbirds as they display for prospective mates.

Today’s featured bird calls as it flies high overhead on our warm summer evenings.

[Kevin Colver recording https://wildstore.wildsanctuary.com/collections/special-collections and https://wildstore.wildsanctuary.com/collections/special-collections]

Those piercing nasal cries are made by Common Nighthawks as they sail effortlessly through the evening air on streamlined wings, their short wide bills agape to intercept flying insects. Periodically, this peaceful scene is disrupted by an unexpected booming sound.

[Kevin Colver recording https://wildstore.wildsanctuary.com/collections/special-collections and https://wildstore.wildsanctuary.com/collections/special-collections]

That was no bullfrog croaking, but the male nighthawk generating feather sounds during a brief nosedive. Their booming display is easily missed, leaving you to puzzle as to the source of such an odd outburst. It lends the nighthawk its other common name, the bullbat, like a bat in flight that sounds like a distant bellowing bull. No other Utah bird makes this sound. So as a fiery summer sunset unfolds, look for nighthawks peacefully plying the sky, and listen for their distinctive booming. We have waited all winter for such lovely moments.

This is Linda Kervin for Bridgerland Audubon Society.
Credits:
Audio: Kevin Colver, https://wildstore.wildsanctuary.com/collections/special-collections
Photos: Courtesy US FWS Digital Library, Thomas G. Barnes Photographer
Text: Jim Cane, Bridgerland Audubon Society

Additional Reading:

Common Nighthawk, Utah Conservation Data Center, Utah Division of Wildlife Resources, https://dwrcdc.nr.utah.gov/rsgis2/Search/Display.asp?FlNm=chormino

Common Nighthawk, All About Birds, The Cornell Lab of Ornithology, https://www.allaboutbirds.org/guide/Common_Nighthawk/lifehistory

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Western Tanager

Western Tanager
Courtesy & Copyright © 2010
Michael Fish

Hi, I’m Holly Strand from Stokes Nature Center in beautiful Logan Canyon.

An exotic-looking bird is making quite a splash this year in Cache Valley. The dazzling plumage of the western tanager creates animated flashes of color in the spring foliage. Catching sight of the brilliant red head and bright yellow body, with contrasting black back, wings and tail some people can’t help but wonder: “Is that a parrot?”

Every spring western tanagers arrive in a migration wave that originates in Central America. But the birds don’t stay with us for very long. Low elevations in Utah represent stopover sites not destinations. The birds are headed for their breeding habitat which is open forests of Douglas fir, spruce and pine to our north and at higher elevations. Migrating at night, the tanagers appear as if by magic one morning, They refuel a bit and then they are off again without much fanfare. Some years I don’t even notice them coming through at all.

But this year, the tanagers aren’t leaving. In fact they seem to be multiplying! So what’s going on?

I spoke with Frank Howe, an avian ecology specialist with the Utah Division of Wildlife Resources. He says the reason we have so many tanagers is the wacky spring weather. The western tanager breeding grounds are still too wintery for these tropical migrants. Therefore, the tanagers are just waiting it out, refueling on high energy insects in Cache Valley as well as other locations along the Wasatch Front. Meanwhile, new birds keep arriving so the tanagers just keep stacking up. Just imagine an airport where flights can arrive, but none can take off.

Very territorial during the breeding season, the western tanager seems quite relaxed and even social during its delay. Which is more than you can say for most human travelers with an unexpected layover. This week, I’ve seen 3 affable males perched close on a suet feeder hanging in our yard.

So let’s assume a prolonged warm spell does finally arrive. ( I know this is a stretch of the imagination for many of us in Northern Utah). But it will happen. And then one bright morning we’ll wake up to find our colorful visitors gone without a trace –having left in the night for their true destination.

Thanks to the Marie Eccles Caine Foundation –the Russell Family for supporting Stokes Nature Center programs.

For Wild About Utah and Stokes Nature Center, I’m Holly Strand.
Credits:
Images: Courtesy & Copyright 2010 Michael Fish
Text:     Holly Strand, Stokes Nature Center
Sources & Additional Reading:


What Bird.com, Field Guide to Birds of North America, https://identify.whatbird.com/obj/196/_/Western_Tanager.aspx

Western Tanager, All About Birds, Cornell Lab of Ornithology, https://www.allaboutbirds.org/guide/Western_Tanager/id

Western Tanager, Piranga ludoviciana, Utah Conservation Data Center, Utah Division of Wildlife Resources, https://dwrcdc.nr.utah.gov/rsgis2/search/display.asp?flnm=piraludo

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Utah’s Desert Fox

Kit Fox, click to view larger image, Photo Courtesy and Copyright © 2009 Bryan Kluever, graduate research assistant, Utah State University Department of Wildland Resources
PhD student Bryan Klueve
with an adult kit fox
that was captured
with a box trap.
Kit foxes are weighed,
fitted with a radio collar,
and then released
Courtesy & Copyright © 2010
Bryan Kluever
Graduate Research Assistant
Utah State University
Dept of Wildland Resources

Hi, I’m Holly Strand from Stokes Nature Center in beautiful Logan Canyon.

The kit fox just might be Utah’s cutest mammal. Weighing in at four to five pounds or so, the kit fox is about a third of the size of the more common red fox.. The kit fox has delicate cat- like features and it has comically large, furry ears. It’s desert-colored coat is tinged with rusty orange finishing in a long black-tipped bushy tail.

The kit fox is the only desert dwelling fox in North America. In Utah, you’ll find it mostly in the western part of the state, where it lives off field mice and jackrabbits as well as insects, birds, amphibians and fish.

The kit fox has evolved a number of adaptations to deal with the desert’s harsh conditions.. First of all those big ears aren’t just for looks. They help the kit fox dissipate body heat through evaporative cooling.

Secondly, kit foxes are nocturnal, avoiding the high temperatures of the daytime hours. During the day they lounge in subterranean dens.

Kit fox legs are relatively short for a fox. That helps them zig-zag through the brush when chasing prey or being chased. And the pads of their paws are furry which gives them better traction in the sandy soil of desert habitats.

Long droughts are common in desert environments and kit foxes have developed ways to deal with them. During a drought, fewer vixens breed and litters become smaller. Kit fox families maintain large territories—larger than necessary for normal years. So when a drought hits, and the population of prey species plummets, the foxes have a larger area in which to hunt.

Adult kit fox prior to being
released. Note the black
collar antenna on the right
side of the fox.
Courtesy & Copyright © 2010
Bryan Kluever

Kit foxes get top marks in water conservation. Little goes in and little comes out.. A kit fox can exist for many months without ever drinking water. Instead, the fox can draw water from the food that it eats. And that water is used with great efficiency. Little is lost through metabolic processes such as urination, defecation breathing and panting.

Too see pictures of the diminitive kit fox, go to www.wildaboututah.org

Thanks to Brian Kleuwer and Mary-Ann Muffoletto of Utah State University’s College of Natural Resources for supporting this Wild about Utah topic.

For Wild About Utah and Stokes Nature Center, I’m Holly Strand.
Credits:
Images: Courtesy & Copyright Bryan Kluever, USU Department of Wildland Resources
Text:     Mary-Ann Muffoletto, Utah State University College of Natural Resources

Additional Reading:

White, P. J. and K. Ralls. 1993. Reproduction and spacing patterns of kit foxes relative to changing prey availability. Journal of Wildlife Management 57:861–867 The Wildlife Society, https://si-pddr.si.edu/dspace/bitstream/10088/510/1/White1993.pdf

Kit Fox (Vulpes macrotis), Wildlife Notebook Series No. 9, Utah Division of Wildlife Resourceswildlife.utah.gov/publications/pdf/2010_kit_fox.pdf

Kit Fox (Vulpes macrotis), Species Fact Sheets, Utah Conservation Data Center, Utah Division of Wildlife Resources, https://dwrcdc.nr.utah.gov/rsgis2/Search/Display.asp?FlNm=vulpvelo