Wild About Utah

February 2, 2015July 9, 2020

Robins in Winter

American Robin
*Turdus migratorius*
Courtesy US FWS, images.fws.gov
Dr. Thomas G. Barnes, Photographer

American Robin
*Turdus migratorius*
Courtesy US FWS, images.fws.gov
Lee Karney, Photographer

Robin with Chicks in Nest
Courtesy US FWS, images.fws.gov
James C. Leopold, Photographer

The American robin with its abundance, red breast, and loud song is one of the most recognizable backyard birds in North America. For many of us the robin – or Turdus migratorius – is also thought of as a herald of spring. So why is it that we still occasionally see them in our wintry Utah backyards?

Seasonal bird migration can be triggered by a number of things, but the two main drivers are food supply and nesting habitat. In spring and summer the birds move northward to take advantage of insect hatches, budding plants, and the plethora of nesting sites. Then, as food sources dwindle in fall, the birds move southward to areas where the necessary resources are still plentiful.

The distances birds migrate in order to access these resources can range widely. Therefore, birds are generally categorized as being short-, medium-, or long-distance migrants. Robins are considered short-distance migrants. While their range spans all of Canada and the United States extending down into Mexico, most robins do not travel far from their breeding grounds in winter and may not leave at all. Only the populations that breed and reside on the edges of this range will migrate seasonally.

The robin’s varied diet and behavioral adaptability are the primary reasons these short-migratory or non-migratory patterns are possible. Robins are preferably ground foragers, feasting on insects and earthworms in the spring and summer months. Yet, during the fall and winter, robins eat a fruit-based diet. They track this seasonal food source in flocks, abandoning their summer individualistic and territorial behavior. These flocks – or roosting aggregates – also help them survive the cold winter temperatures. As a result, robins are able to cope with the ground freezing, the disappearance of their preferred food source, and the harsh winter weather.

Returning to our original question: is the American robin truly a sign of spring here in Utah? Is it strange to see this bird in our backyards during the winter months? The simple answer is no. Robins can be found year round almost anywhere south of Canada. While they may migrate nomadically, staying or leaving areas as weather and snow cover affect their food supply, there could be some keeping us company in Utah all winter.

For Wild About Utah, I’m Anna Bengtson.

Credits:
Image: Courtesy US FWS, Lee Karney, James C. Leopold, Photographers
Text: Anna Bengston

Sources & Additional Reading:

American Robin Profile, Utah Birds https://utahbirds.org/birdsofutah/BirdIndex.htm

American Robin, Cornell Lab of Ornithology https://www.allaboutbirds.org/guide/american_robin/id

American Robin, The Birds of North America Online https://bna.birds.cornell.edu/bna/species/462/articles/introduction

Studying Migration, Cornell Lab of Ornithology https://www.birds.cornell.edu/AllAboutBirds/studying/migration/

Migration Patterns, Cornell Lab of Ornithology https://www.birds.cornell.edu/AllAboutBirds/studying/migration/patterns

Where Have all the Robins Gone?, Migration, Cornell Lab of Ornithology https://www.birds.cornell.edu/AllAboutBirds/faq/master_folder/migration/document_view

Snow Depth Survey, The Great Backyard Bird Count https://www.birdsource.org/gbbc/science-stories/past-stories/snow-depth-survey

Winter Robins, The Great Backyard Bird Count https://www.birdsource.org/gbbc/science-stories/past-stories/is-that-winter-flock-of-robins-in-your-yard-unusual

Kelly, Patrick, A Moral Dilemma, Wild About Utah, June 29, 2020, https://wildaboututah.org/a-moral-dilemma/

Bengston, Anna, Robins in Winter, Wild About Utah, March 13, 2014, https://wildaboututah.org/robins-in-winter/

Bengston, Anna, American Robin, Wild About Utah, January 18, 2016, https://wildaboututah.org/american-robin-160118/

Bingham, Lyle, Richard Hurren(voice), The Occupants on Robin Street, Wild About Utah, July 8, 2008, https://wildaboututah.org/the-occupants-on-robin-street/

January 26, 2015January 24, 2021

Dark-eyed Juncos

Click for a larger view of a Dark-eyed 'Oregon' Junco Male, Junco hyemalis montanus, Courtesy and copyright 2008 Ryan P. O'Donnell — Dark-eyed Junco “Oregon” Male
*Junco hyemalis montanus*
Courtesy & © 2008 Ryan P. O’Donnell

Dark-eyed Junco “Oregon” Female
*Junco hyemalis montanus*
Courtesy & © 2011 Ryan P. O’Donnell

Dark-eyed Junco “Pink Sided”
*Junco hyemalis mearnsi*
Courtesy & © 2011 Ryan P. O’Donnell

Dark-eyed Junco “Cassiar”
*Junco hyemalis cismontanus*
Courtesy & © 2011 Ryan P. O’Donnell

Dark-eyed Junco “Gray-headed”
*Junco hyemalis caniceps*
Courtesy & © 2011 Ryan P. O’Donnell

Click for a larger view of a Dark-eyed 'Oregon' Junco Female, Junco hyemalis montanus, Courtesy and copyright 2011 Ryan P. O'Donnell — Dark-eyed Junco “Oregon” Male
*Junco hyemalis montanus*
Courtesy & © 2008 Ryan P. O’Donnell

Dark-eyed Junco “Oregon” Female
*Junco hyemalis montanus*
Courtesy & © 2011 Ryan P. O’Donnell

Dark-eyed Junco “Pink Sided”
*Junco hyemalis mearnsi*
Courtesy & © 2011 Ryan P. O’Donnell

Dark-eyed Junco “Cassiar”
*Junco hyemalis cismontanus*
Courtesy & © 2011 Ryan P. O’Donnell

Dark-eyed Junco “Gray-headed”
*Junco hyemalis caniceps*
Courtesy & © 2011 Ryan P. O’Donnell

My backyard bird feeders are a busy place this time of year. I enjoy keeping track of who visits – especially as a relative newcomer to the Utah bird scene. Last winter, however, I was baffled by the identity of what turned out to be a fairly ordinary bird.

Dark-eyed juncos are a common sight throughout the United States, but as it turns out, they exhibit an incredible geographic variation in plumage colors. There is a ‘slate-colored race’ which I was used to seeing in the Midwest – uniformly gray above with a white underbody. During Utah winters, the ‘Oregon race’ is common, with its black hood, brown back and peachy sides. Another ‘gray-headed race’ sports varying shades of gray with a distinct reddish brown patch on its back.

Depending on who you ask, there are up to fifteen different races, also called sub-species, of dark-eyed junco – all quite visually distinct, but all considered to be the same species. It wasn’t always this way, however. In the late 1950’s what we now call dark-eyed juncos were recognized as four different species, and in the 1890’s there were six.

These changes beg the question, at what point does speciation occur? And the answer lies in the ability of these birds to interbreed. One scientific definition of a species is those organisms or populations of organisms that are “potentially capable of interbreeding.”

Unique plumage patterns have evolved in a number of geographic locations across the junco’s range, however all of the dark-eyed junco variants could potentially interbreed if they happened to meet. Indeed in places where these geographic territories overlap inter-breeding does take place resulting in blends of the usually-distinct color patterns.

Juncos aren’t the only bird species with recognized color variants. Any raptor enthusiast will be familiar with variations in plumage colors that many birds of prey exhibit, such as merlins and red-tailed hawks. What makes dark-eyed juncos unique is that they are being studied as a possible case of speciation in progress. It turns out that there is more than just a difference in color among dark-eyed juncos. Some sub-species also exhibit variation in song patterns, social behavior, body size, and migration patterns, any of which may eventually cause these groups to stop interbreeding and allow a new species to emerge.

To see pictures of dark-eyed junco subspecies, visit our website at www.wildaboututah.org. Thank you to Rocky Mountain Power Foundation for supporting the research and development of this Wild About Utah topic.

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

Credits:

Photos: Courtesy & © Ryan P. O’Donnell
Text: Andrea Liberatore, Stokes Nature Center, logannature.org

Additional Reading:

Atwell, J.W., O’Neal, D.M, and Ketterson, E.D. (2011) Animal Migration as a Moving Target for Conservation: Intra-species Variation and Responses to Environmental Change, as Illustrated in a Sometimes Migratory Songbird. Environmental Law. Vol. 41:289 p. 289-319, https://www.amazon.com/Animal-migration-moving-target-conservation/dp/B005C29H7I

Alderfer, Jonathan (editor) (2005) National Geographic Complete Book of Birds. National Geographic Press. Dark-eyed junco information available online at: https://animals.nationalgeographic.com/animals/birding/dark-eyed-junco/

Cornell Lab of Ornithology, All About Birds: Dark-eyed Junco. https://www.allaboutbirds.org/guide/Dark-eyed_Junco/id/ac

History of Name Changes for Juncos. Cornell Lab of Ornithology. https://www.birds.cornell.edu/pfw/News/junco_taxonomy.pdf

January 22, 2015March 1, 2018

Riparian Zones and a Critter Quiz

Hello, this is Jim Goodwin.

In a minute I’ve got a critter quiz for you, but first, a word about the huge importance of riparian areas in semi-arid Utah, the second driest state in the union. Utah State’s Extension Service calls riparian zones the green ribbon of life alongside a stream. They are shadier, cooler and moister than adjacent environments.

And with a diverse mix of plants and animals, our few riparian corridors are heavily used by wildlife for food, rest and shelter.

Ok, now for our critter quiz.

What is the largest rodent in North America? Here’s a hint: they can be up to four feet long and weigh 40 to 60 pounds.

Did that do it? No? Alright, this clue will: They spend much of their life in water. They have a beautiful brown coat, a broad flat hairless tail and big orange buck teeth that continually grow, which is why they chew and chew and chew.

Click for larger picture, Beaver with branch in water, Courtesy US FWS, Steve Hillebrand, Photographer — Beaver with branch in water
Courtesy US FWS,
Steve Hillebrand, Photographer

Good, you got it . . . it’s the North American beaver. Or as Utah environmental author Chip Ward calls them: the Flat Tail Climate Hero for the restoration of damaged watersheds. Beaver are amazing aquatic engineers, second only to humans in their ability to manipulate their environment.

In our nation’s history, they’ve played a big role in literarily shaping our western landscape.
Joe Wheaton, Utah State wildlife and a beaver expert, rightly calls the work of the beaver “cheap and cheerful restoration” of our heat stressed watersheds.

In the wild, these mostly nocturnal animals, normally live five to ten years.
Fortunately, they are rarely killed for their pelts these days. Beaver are usually monogamous. They will produce up to 10 babies. The young kits will stay home until they are two or so, before they will take off on their own.

Beaver are master aquatic builders. the original geo-engineers. They build dams to flood areas for protection from predators, for access to their food supply, and to provide safe underwater entrances to their dens. Their dams create beautiful riparian habitat for many other animals, birds, fish amphibians, insects and plants. The flooded areas slow the flow of water and sediment downstream and raise the area water table.

Aspen, cottonwood, willow and dogwood are their preferred tree. Those trees regenerate quickly after beaver topple them. When their ponds freeze over, beaver jam smaller branches into the mud at the bottom of their pond for food storage.

Beaver dams can be 5 to 10 feet high and 150 feet across. They are constructed with branches, stones, and plants and plastered together with mud. Over 1200 beaver dams have been counted in northern Utah’s Bear River mountains alone. The World’s largest beaver dam in Canada is 2,789 feet in length. That’s more than 9 football fields.

Yes, sometimes beaver can be a nuisance to human property and activities. Often, learning to live with beaver and the many benefits they can bring, can be a solution. There are simple time-tested ways to prevent flooding. But if nothing works, they can be live trapped and moved to another area. There’s no need to shoot them.

Be a “beaver believer.” Here are some organizations you can check with to learn more:
Utah State wildlife researchers Wally McFarland and Joe Wheaton have created something called the Beaver Restoration Assessment Tool to track beaver dam building activities and their effects throughout the state.
The Bear River Watershed Council in Cache Valley and Mary O’Brien with the Grand Canyon Trust in southern Utah are excellent organizations to contact.

I’m Jim Goodwin for Wild About Utah.

Credits:
Image: Courtesy US FWS, Steve Hillebrand, Photographer
Text: Jim Goodwin
Additional Reading:

Beaver Restoration Assessment Tool, https://brat.joewheaton.org/

Bear River Watershed Council, https://www.brwcouncil.org/

Grand Canyon Trust, https://www.grandcanyontrust.org/

Beaver Castor canadensis, National Geographic, https://animals.nationalgeographic.com/animals/mammals/beaver/

Big Bend Habitat Restoration Project: A Natural Work of Heart, Open Spaces-A Talk on the Wild Side, US FWS, https://www.fws.gov/news/blog/index.cfm/2016/3/25/Big-Bend-Habitat-Restoration-Project-A-Natural-Work-of-Heart [Accessed March 31, 2016]

Beaver Dams Strengthened by Humans Help Fish Rebound
60-Second Science – July 25, 2016 – By Jason G. Goldman02:29 https://www.scientificamerican.com/podcast/episode/beaver-dams-strengthened-by-humans-help-fish-rebound/ Also available through the podcast https://itunes.apple.com/us/podcast/60-second-science/id189330872?mt=2

January 12, 2015August 23, 2023

Pot Holes and Fairy Shrimp

Aerial view of potholes in Navajo sandstone, Grand County, Utah. Photo Courtesy USGS — Aerial view of potholes in Navajo sandstone, Grand County, Utah.

Photo Courtesy USGS

Adult fairy shrimp
*Branchinecta packardi.*
Photo Courtesy USGS

Adult Vernal Pool Fairy Shrimp
*Branchinecta lynchi*
Photo Courtesy USGS

Click to view larger image of , Photo Courtesy USG — Aerial view of potholes in Navajo sandstone, Grand County, Utah.

Photo Courtesy USGS

Adult fairy shrimp
*Branchinecta packardi.*
Photo Courtesy USGS

Adult Vernal Pool Fairy Shrimp
*Branchinecta lynchi*
Photo Courtesy USGS

Shrimp in the desert landscape of Canyonlands National Park? Yep. You can find them, –fairy shrimp– when the rainy season arrives and turns dry, dusty potholes into water-filled rock basins brimming with life.

A surprising array of creatures relies on these potholes for life, and one of the most curious is the fairy shrimp. These unique crustaceans are found in small potholes that dot sandstone outcrops found in America’s Southwest. Their eggs maintain resilience during the dry season, and when spring rains arrive, the shrimp hatch.

There are more than 300 varieties of fairy shrimp, the most common being the Vernal Pool Fairy Shrimp. These little guys measure between a half-inch to one-and-a-half inches long as adults. They can be found anywhere ephemeral pools are present, though the majority of their population resides in California and Oregon.

Fairy shrimp vary in color depending on the menu found in their particular pool of residency, ranging from translucent, to orange, even to blue! They feature 11 pairs of legs to propel themselves upside-down, or more scientifically, ventral side-up.

They also use these incredibly helpful legs to eat unicellular algae, ciliates (sil-ee-its), and bacteria by filter and suspension feeding methods. They filter-feed by pumping water through filtration structures — located in their multi-purpose legs — thus capturing the food. They also are adept at suspension feeding by plucking food floating in the water, again, with their tentacle-like legs. They may also grab or scrape food from the surfaces of other things in their vernal pool, such as sticks and rocks.

What’s truly amazing is how fairy shrimp reproduce. They typically lay drought-tolerant eggs during the summer that over-winter in the dried sediment on the pot hole bottom and then hatch in the spring when the potholes fill with rainwater However, if drought sets in, eggs can be transferred to other pools by floating in gusts of wind or being carried by a particularly curious animal.

These eggs are tough and can withstand varying temperatures, drought, and even the test of time; eggs in laboratory settings have survived intact up to 15 years before hatching.

Under the right conditions, you can observe fairy shrimp in Canyonlands, Arches, and Death Valley national parks. Canyonlands and Arches boast at least two species of fairy shrimp: the Packard Ferry Shrimp, also known as the Rock Pool Ferry Shrimp or the Arizona Ferry Shrimp, and the Great Plains Ferry Shrimp.

Fairy shrimp hatch in the Spring, right after the potholes and vernal pools re-fill with water, so that will be your prime time to look for these interesting creatures. As travelers, you can do your part to help the fairy shrimp by leaving their vernal pools alone. Drinking water, stepping in, or touching a pool can throw off the entire mini-eco-system located in this fascinating habitat.

And remember, our fingers are very salty, so even if you’re using a gentle touch, do not put your fingers in a vernal pool, as it just might raise the salinity and throw off the dissolved oxygen percentage needed for fairy shrimp to survive.

For Wild About Utah and National Parks Traveler, I’m Kurt Repanshek.

Credits:
Image: Courtesy and Copyright Kurt Repanshek, www.nationalparkstraveler.com
Text: Kurt Repanshek, NationalParksTraveler.com.
Additional Reading:

https://digitallibrary.utah.gov/awweb/awarchive?type=file&item=22782

https://www.nwf.org/wildlife/wildlife-library/invertebrates/vernal-pool-fairy-shrimp.aspx

https://www.arizonafairyshrimp.com/fairyshrimp.html

https://geochange.er.usgs.gov/sw/impacts/biology/vernal/

https://www.nasa.gov/centers/dryden/news/X-Press/shrimp_spotlight.html

https://www.fws.gov/sacramento/es_kids/Vernal-Pool-Fairy-Shrimp/es_kids_vernal-pool-fairy-shrimp.htm