Linda Kervin, Author at Wild About Utah

May 1, 2014December 4, 2023

Medusahead Rye

Weedy plants of old world origin threaten natural areas throughout the United States. An invading plant colonizing a completely new area often lacks the insects, diseases and herbivores that kept it in check back in its native homeland. If the introduced plant grows and spreads vigorously, it can spell disaster for the native inhabitants of its new home. With no natural controls in place, it may outcompete native plants and greatly diminish biodiversity. Disturbed or degraded habitats are most susceptible to invasion by Eurasian weeds.

Utah hosts many invasive weeds causing problems throughout the state. One Eurasian grass threatening sagebrush habitat and rangeland is medusahead rye. Medusahead rye probably came to the United States as a seed contaminant in the 1880’s. The seed head is heavy, so on its own, cannot spread far. But the seeds do have a ticket for dispersal: tufted hairs which cling and readily attach to livestock and vehicles. Once on site, medusahead grows vigorously, crowding out other plants.

Medusahead tissue contains abundant silica which slows its decomposition. The accumulation of dead material forms a dense thatch that smothers other plants. This dry thatch layer can also fuel wildfires. In addition, the gritty silica makes medusahead unpalatable, so both domestic and wild grazing animals avoid eating it. Infested ranches can lose 3/4 of their grazing capacity.

Sage grouse are already in trouble due to habitat loss, and medusahead has invaded more than 10 million acres of the sage brush that sage grouse call home. Once invaded by medusahead, sagebrush habitat is very difficult to restore. The best hope is to prevent or at least hinder its spread through management using controlled burns, herbicides and careful grazing. Non-native, invasive plants are among the most serious threats to our natural world and the habitats and species we know and love.

This is Linda Kervin for Bridgerland Audubon Society.

Credits:

Images: Courtesy Steve Dewey & www.invasive.org
Center for Invasive Species and Ecosystem Health, University of Georgia
Theme: Courtesy & Copyright Don Anderson as performed by Leaping Lulu
Text & Voice: Linda Kervin, Bridgerland Audubon Society

Additional Reading:

Linda Kervin’s pieces on Wild About Utah

The United States National Arboretum. formerly https://www.usna.usda.gov/Gardens/invasives.html

National Invasive Species Information Center. https://www.invasivespeciesinfo.gov/plants/medusahead.shtml

Forest Service Employees for Environmental Ethics. https://www.fseee.org/component/content/article/1002329

Utah State University Cooperative Extension. https://extension.usu.edu/cache/files/uploads/Medusahead%202-10.pdf

April 3, 2014October 29, 2024

Cloud classification

Who has not indulged in the idle pastime of watching puffy white clouds pass overhead, naming their shapes as they form? Of course, such whimsical names do not serve comparative description and understanding. For this, a lexicon of clouds is needed. Our formal cloud classification system traces back to 1803, when an Englishman, Luke Howard, published “An essay on the modifications of clouds”. Luke Howard owned a profitable pharmaceutical company, which funded his gentlemanly meteorological pursuits. Mr. Howard wisely chose a Latin cloud vocabulary to name and illustrate three fundamental cloud types.

The highest flying clouds he named cirrus, meaning curl or tuft, as of hair. These wispy clouds often resemble fibers; one form is the aptly named horse-tail cirrus. Composed of ice crystals, cirrus clouds form at around 30,000 feet, about the cruising altitude of passenger jets. Wispy cirrus clouds often portend a stormy Pacific low-pressure system en route to Utah.

Howard dubbed a type of lower elevation cloud cumulus, meaning mass or heap. These grow from mere puffs to big flat-bottomed clouds with white cauliflower tops. For sheer meteorological beauty, nothing beats legions of fair weather cumulus scudding across a bluebird sky atop a montane backdrop.

The lowest cloud form is stratus. Forming below 8000 feet, they appear as an extensive deck of unbroken gray. Stratus clouds often bring Utah’s winter snowstorms and spring rains. Nimbostratus are responsible for Seattle and Portland’s endless winter drizzle. In contrast, our Utah summer rains fall from towering cumulonimbus thunder heads. These ominous clouds are powered by hot summer updrafts and the steamy humidity that flows northward with the North American monsoon.

Luke Howard’s cloud-naming convention includes 10 principal types in all which easily lend themselves to naming combinations. You can now envision the height and appearance of cirrocumulus clouds, for instance. Cirrus, cumulus, stratus, nimbus, the cloud lexicon of amateur meteorologist Luke Howard has endured for over 200 years. Pictures of these cloud types with a link to the pages of Howard’s original published treatise can be found at our Wild About Utah website.

This is Linda Kervin for Bridgerland Audubon Society.

Credits:
Images: Courtesy NOAA and
Courtesy & Copyright Jim Cane
Text: Jim Cane, Bridgerland Audubon SocietyBridgerland Audubon Society, https://bridgerlandaudubon.org/
Voice: Linda Kervin, Bridgerland Audubon SocietyBridgerland Audubon Society, https://bridgerlandaudubon.org/

Additional Reading:

Luke Howard. 1803. “Essay on the modifications of clouds by “3rd ed. Published 1865 by John Churchill & Sons in London .
https://archive.org/details/essayonmodifica00howagoog and
https://books.google.com/books?id=7BbPAAAAMAAJ&printsec=frontcover#v=onepage&q&f=false

Riehl, Herbert. 1978. “Introduction to the Atmosphere.” McGraw-Hill, NY.
https://www.amazon.com/Introduction-Atmosphere-Herbert-Riehl/dp/0070526567

International Cloud Atlas, World Meteorological Organization,https://cloudatlas.wmo.int/home.html

March 6, 2014December 4, 2023

Golden Eagles

On a recent Christmas Bird Count, my team witnessed an amazing feat of flight. We parked in a subdivision cul-de-sac to walk into the sagebrush foothills. Overhead we saw two Golden Eagles meet in a talon lock and tumble towards earth. They disengaged moments before crashing and flew off in opposite directions. A minute later and we would have missed it all. So what were they up to? I am not quite sure.

Golden Eagles are supreme flyers. In both courtship and territory displays they steeply dive and swoop upward. During a pendulum display, they dive and rise in one direction then turn and retrace their path. Pairs often play with an object in the sky, repeatedly dropping and retrieving it. The talon lock display is rarely seen, but it too is used both for bonding between pairs and in territorial disputes. We saw the display in December and the birds separated immediately, so we probably witnessed a territorial defense. Golden Eagles require a territory anywhere from 20 to 200 square miles depending on prey abundance. As with most wildlife, loss of habitat is a prime threat.

Three quarters of recorded Golden Eagle deaths can be traced to humans. In treeless areas, power poles provide a convenient perch. When their 7 foot wingspan touches two wires, they are electrocuted. New designs and retrofits for power poles eliminate this problem and the resulting range fires, but many of the older designs remain. Wind farms also kill eagles, but again, new designs and more careful siting are helping to alleviate this problem.

The Golden Eagles’ favorite meal in the West is jackrabbit. However, they are opportunistic foragers and will dine on carrion. If the carcass they feed on was shot, they may ingest fragments of bullets or buckshot that contain lead. Lead poisoning is an excruciating way to die. Carcasses with lead fragments are eaten by many carnivorous birds and mammals who are then poisoned. This winter, 8 Bald Eagles died of lead poisoning at the Wildlife Rehabilitation Center of Northern Utah. We must remedy this problem so we can insure that our skies will always be graced by the grandeur of soaring eagles.

Our theme music was written by Don Anderson and is performed by Leaping Lulu.

This is Linda Kervin for Bridgerland Audubon Society.

Credits:

Image: Courtesy USDA Forest Service, Dave Herr, Photographer
Theme: Courtesy & Copyright Don Anderson as performed by Leaping Lulu
Text & Voice: Linda Kervin, Bridgerland Audubon Society

Additional Reading:

Linda Kervin’s pieces on Wild About Utah

https://www.allaboutbirds.org/guide/golden_eagle/lifehistory

https://www.hawkwatch.org/component/content/127

https://www.peregrinefund.org/explore-raptors-species/Golden_Eagle#sthash.Gqowt1G0.gFqVfifi.dpbs

https://www.deseretnews.com/article/865596763/Lead-blamed-for-latest-bald-eagle-deaths-in-Utah.html

October 31, 2013December 4, 2023

Shrikes

Loggerhead Shrike
*Lanius ludovicianus*
Copyright 2013 Linda Kervin

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

Northern Shrike Courtesy US FWS, Dave Menke, Photographer — Loggerhead Shrike
*Lanius ludovicianus*
Copyright 2013 Linda Kervin

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”