Wild About Utah

April 4, 2013March 4, 2026

Why Some Birds Flock in the Vee Formation

Spring is that magical season when avian migrants return north from more balmy climates. Utah’s migrants range from ponderous pelicans to tiny hummingbirds, honking geese to crying curlews. Many arrive as they departed, in flocks.Why Some Birds Flock in the Vee Formation

Kevin Colver: Songbirds of Yellowstone, Canada Goose)

But why fly in a flock at all? One reason is predator evasion, the same reason that minnows school and elk, bison and deer bunch in herds. Embedded in a swirling mass of birds called a swarm flock, an individual bird is less likely to be picked off by an aerial predator, such as a falcon or a Cooper’s Hawk. A raptor diving into a swarm flock risks collision and injury. Targeting a bird in a swirling group is visually difficult too. Flying in a flock gains safety, but at what cost? Pigeons flying in a swarm flock take shallower, more frequent wing strokes than a solo bird. Faster wing beats probably provide more control to better negotiate turbulent aerial traffic, but extra flapping costs more in energy.

In contrast, pelicans and other big birds often fly in tidy formation flocks. Flying in a vee formation, a trailing pelican’s heart beats 13% slower than the lead bird. That’s because a trailing pelican flaps less than the leader. Unlike pigeons, then, a pelican flying in a formation flock uses less energy, not more. Big birds with slow wing beats share aerodynamic attributes with airplanes. Some of the air under their wings swirls out from under the tips, creating a spiraling vortex that trails the wing tip. Flying in a tight vee formation, each trailing bird gets a bit of lift from the upwash created by that vortex, and so it can flap a little less and glide a little more. Lead birds tire more quickly, so leaders change periodically. Leaders lose their zip, not their way. In a vee, birds also have their flock mates in good view, which is needed for the tight precision of a formation flock.

(Kevin Colver: Songbirds of Yellowstone, Sandhill Crane)

Pelicans, swans, geese, cranes, ibis, ducks, godwits, they all ply the Utah sky in formation flocks. They may be bird-brained, but our bigger migrants know a thing or two about aerodynamics.

Credits:
Images: Courtesy & Copyright Brenda Bott, Photographer
Text: Jim Cane, Bridgerland Audubon Society https://www.bridgerlandaudubon.org

Video:

Spectacular flock (called a “murmuration”) of starlings, Sophie Windsor Clive & Liberty Smith, https://www.youtube.com/watch?v=iRNqhi2ka9k As viewed from Islandsandrivers.com. Contains advertisements.

Van Ijken, Jan, Flight of the Starlings, National Geographic, Nov 15, 2016, https://youtu.be/V4f_1_r80RY
See also https://www.janvanijken.com/film-projects/the-art-of-flying/theartofflyingfullversion/

Additional Reading:

Avian flight by John J. Videler. 2005. New York, Oxford University Press. 258 pp.
Contents:

Acquisition of knowledge
The flight apparatus
Feathers for flight
Aerodynamics
Evolution of bird flight
Bird flight modes
The bird flight engine
Energy required for flight
Comparing the metabolic costs of flight

Usherwood JR, Stavrou M, Lowe JC, Roskilly K, Wilson AM. 2011. Flying in a flock comes at a cost in pigeons. Nature. 2011 Jun 22;474(7352):494-7. https://www.researchgate.net/publication/51242928_Flying_in_a_flock_comes_at_a_cost_in_pigeons

Weimerskirch H; Martin J; Clerquin Y; Alexandre P; Jiraskova S. 2001. Energy saving in flight formation. Nature. 413: 697-698. https://eol.org/data_objects/16885552

March 28, 2013July 18, 2022

Oolites

Click to view larger image of the Utah's Oolitic Sand, Photo Courtesy and Copyright Mark Larese-Casanova — Utah’s Oolitic Sand, Photo Courtesy and Copyright Mark Larese-Casanova

Hi, this is Mark Larese-Casanova from the Utah Master Naturalist Program at Utah State University Extension.

Imagine if prehistoric brine shrimp were responsible for one of the finest examples of architecture in Salt Lake City today.

Okay, so it may be a bit of a stretch, but let me explain. In a previous episode of Wild About Utah, I discussed the life cycle of brine shrimp and the important role that they play in the Great Salt Lake Ecosystem. Well, as the billions of brine shrimp feed on bacteria in Great Salt Lake, they excrete waste in the form of tiny fecal pellets. These pellets, along with sand grains and other bits of debris, eventually settle to the bottom of Great Salt Lake.

In shallow areas of the lake, where wind and waves routinely mix the water, these small particles gradually accumulate layers of calcium carbonate, forming an oolite (spelled o-o-l-i-t-e). This is very similar to how a pearl, also layers of calcium carbonate around a small particle, is formed within the shell of an oyster or mussel. The main difference, aside from a pearl being much larger, is that oolites are typically oblong, rather than round. The beaches on the west side of Antelope Island are a great place to find oolitic sand, which will look and feel as though you have a handful of tiny pearls.

Click to view larger image of the Utah's Oolitic Sandstone, Photo Courtesy and Copyright Mark Larese-Casanova — Utah’s Oolitic Sandstone
Photo Courtesy & Copyright
Mark Larese-Casanova

Around 50 million years ago, large fresh- and salt-water lakes covered parts of Utah, and in these areas, vast amounts of sediments, including oolites, were deposited. Over time, these oolites were compressed and cemented together into limestone.

A quarry near Ephraim in Sanpete County supplied oolitic limestone for the construction of the Governor’s Mansion in 1902 and the original Salt Lake City Public Library in 1905. The Library building, located at 15 South State Street, eventually housed the Hansen Planetarium and is now home to the O.C. Tanner flagship store. The building underwent an extensive restoration just a couple of years ago, and now serves as a shining example of neoclassical architecture in our capitol city.

The truth is, there are tens of millions of years separating oolitic limestone from our modern-day brine shrimp. So, we can’t exactly say that prehistoric brine shrimp were responsible for the existence of the O.C. Tanner building. But, it’s fun to imagine precious gems from around the world housed in a beautiful building constructed from the ‘pearls’ of Great Salt Lake.

Click to view larger image of the historic OC Tanner building made from oolitic sandstone (This building formerly housed the Salt Lake Library and Hansen Planetarium), Photo Courtesy and Copyright Mark Larese-Casanova — Historic OC Tanner Building
(formerly the Salt Lake Library
and later the Hansen Planetarium)
Photo Courtesy & Copyright
Mark Larese-Casanova

For Wild About Utah, I’m Mark Larese-Casanova.
Credits:

Images: Courtesy and copyright Mark Larese-Casanova

Text: Mark Larese-Casanova, Utah Master Naturalist Program at Utah State University Extension.
Additional Reading:

Utah Geological Survey https://geology.utah.gov/utahgeo/rockmineral/collecting/oolitic.htm

Utah Division of Wildlife Resources, Great Salt Lake Ecosystem Program
https://wildlife.utah.gov/gsl/facts/oolitic_sand.php

Salt Lake Brine Shrimp, https://saltlakebrineshrimp.com/harvest/

March 21, 2013July 12, 2020

2013 Desert Wildflower Forecast

Click for a larger view of a Dark-eyed 'Oregon' Junco Male, Junco hyemalis montanus, Courtesy and copyright 2008 Ryan P. O'Donnell — Claret cup cactus in bloom
Arches National Park
Echinocereus triglochidiatus
var. melancanthus
Courtesy NPS, Neal Herbert, Photographer

Hi, I’m Holly Strand.

It’s showtime for desert wildflowers in CA, AZ and NM. But in Utah’s deserts think April or May. Within those months the exact timing, type and quantity of blooms are highly variable. Flowering depends upon the pattern of precipitation from fall onward and on spring temperatures, sunlight and elevation. And of course, on the specific ecological requirements of each particular plant.

Annuals are plentiful in the desert. Annual plants germinate, grow, flower, set seed and die all within one season—often in the spring. To avoid water stress—some annuals will start their life cycle only when there is significant moisture. If it’s dry, they may stay in seed form waiting for better conditions. Likewise, many perennials—plants that live more than 2 years—can remain below ground as dormant bulbs, corms or roots. But when conditions are right, these water stress avoiders –both annuals and perennials–will flourish. When this happens we call it a “good year” for wildflowers.

I couldn’t find a wildflower hotline for Utah—so I called different parks representing Utah’s 3 different desert regions to get a flower forecast for 2013.

Nothing much is happening yet on the Colorado Plateau in and around Arches and Canyonlands National Parks. It’s been pretty cold according to staff ranger Sharon Brussell. So the appearance of spring flowers is somewhat delayed. But in April we can expect to see evening primrose, twinpods and milk vetches. And in late April-early May, Princes’ plume, globemallow and yucca. The scarlet blooms of claret cup cactus will follow. If you miss what you are looking for in Arches or the Needles district, just go higher to Islands in the Sky, adds Nathaniel Clark of the Canyonlands National Park. Here–because of the elevation–flowering of similar species occurs 2-4 weeks later.

Snow Canyon is in the Mojave Desert region. Park Manager Kristen Comella told me that this is likely to be a typical year for wildflowers. Spectacled pod and lotus vetch are already out. Soon we’ll see bright yellow flowers of the Mojave’s signature creosote bush, and the deep purple flowers of indigo bush. Prickly pear and Utah yucca will soon follow. If you want to see early spring blooms on Joshua trees, go south on old highway 91 from Gunlock to see Utah’s one and only Joshua Tree forest.

To find out what’s happening in the Great Basin I spoke with Ben Roberts at Nevada’s Great Basin National Park. He says there has been a bit less precipitation than normal but it should still be an OK year for flowers. So far he’s only spotted one — Nevada lomatium. This brave little plant blooms even when there is snow still lying around. From a distance you might even think the low-lying white flowers are a patch of snow. In April desert paintbrush will appear, as will arrow-leaf balsamroot and purple sage. Wild iris, blue flax and prickly pear will follow in May.

For sources and pictures and suggestions for good desert wildflower hikes go to www.wildaboututah.org

For Wild About Utah, I’m Holly Strand.

Credits:
Image: Courtesy NPS, Arches National Park, Neal Herbert, Photographer
Text: Holly Strand

Recommended hikes for viewing wildflowers

Great Basin National Park (Great Basin)
Baker Creek Trail
Lehman Creek Trail
Pole Canyon Trail

Arches National Park (Colorado Plateau)
Primitive Loop

Canyonlands National Park (Colorado Plateau)
Neck Spring Trail—Islands in the Sky

Snow Canyon State Park (Mojave Desert)
Hidden Canyon
Whiptail Trails

Sources & Additional Reading

Arches Flower Guide (by color, month, name and keys)https://www.nps.gov/arch/naturescience/flowerguide.htm

Comstock, J. and J. Ehrlinger 1992. Plant adaptations in the Great Basin and Colorado Plateau. Great Basin Naturalist. Vol. 52. No. 3

Fertig, Walter. 2010. Utah’s Mojave Desert Flora. Sego Lily, newsletter of the Utah Native Plant Society. Vol. 33, No. 2. https://www.unps.org/segolily/Sego2010MarApr.pdf

McMahon, James. 1985. Deserts (National Audubon Society Nature Guides) NY: Alfred A. Knopf https://www.amazon.com/Deserts-National-Audubon-Society-Nature/dp/0394731395

Williams, David. 2000. A Naturalist’s Guide to Canyon Country. A Falcon Guide. Helena MT. Published in cooperation with Canyonlands Natural History Association.https://www.amazon.com/Naturalists-Guide-Canyon-Country-Williams/dp/1560447834

March 14, 2013January 31, 2026

Dark-eyed Juncos

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:

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