American Invasion

Eurasian Collared Dove, Courtesy invasivespecies.org, Joy Viola, Northwestern University, Photographer
Eurasian Collared Dove
Streptopelia decaocto
Courtesy & © invasivespecies.org/bugwood.org
Joy Viola, Northwestern University, Photographer

Colorado Potato Bug, Courtesy insectimages.org/bugwood.org, USDA ARS, PhotographerColorado Potato Beetle Adult
Leptinotarsa decemlineata
Courtesy IPMimages.org/bugwood.org
USDA ARS, Photographer

Hi, I’m Holly Strand from the Quinney College of Natural Resources at Utah State University.

More and more you are likely to hear this sound in Utah yards, parks and fields. [Eurasian Collared Dove, Courtesy Ryan O’Donnell, www.xeno-canto.org/98068] That’s the call of the Eurasian collared dove. Originally from Asia, this dove has been expanding its territory around the world at an incredible rate. The first sighting in Utah was in Orem in 1997. And now the doves are everywhere. So far, it doesn’t look like our native mourning dove is affected. But such rapid population explosions rarely occur without some sort of undesirable ecological consequence.

In America, the Eurasian collared dove is an invasive species. But not all non-native species are invasive. “Invasive” only applies when species spread far beyond the area where they are first introduced. Luckily, not all invasive species turn out to be serious pests. Ecologist Mark Williamson suggested the tens rule. About 10% of introduced species establish lasting populations and 10% of those go on to become problems.

There’s a long list of Eurasian invasives in Utah. Among them is the highly flammable cheat grass that comes from southwestern Asia. Those massive clouds of starlings? They come from Europe. Tamarisk from Eurasian deserts lines the Colorado River and tributaries. The common carp is an unwelcome Eurasian colonist of our lakes and large rivers. And the American west’s iconic tumbleweed is an invader from the Russian steppe.

Why so many invaders from Eurasia? Well for the last 500 years, there has been a net outflow of Eurasians—especially Europeans—to other parts of the world. And this human population carried its biological baggage along with it—in the form of animals, plants and diseases. Some ecologists believe that the physical geography and human history of Eurasia has conditioned its species in such a way that they will consistently outcompete the species of other continents. But that’s debatable. For in the last decades the New World has started to lob some pretty competitive species over to Eurasia.

For example, the American mink was brought to the Eurasian continent in the 1920s for use on fur farms. But–because of deliberate releases and accidental escapes–the mink is now common in the European wild. And it’s a pest. The American mink is taking the place of the European mink which is now threatened with extinction. Furthermore, the American mink is gobbling up populations of many ground-nesting birds.

Unless you are involved in agriculture, you might not have heard of the Colorado potato beetle. But potato growers around the globe know this striped orange and brown beetle from the American southwest very well. It has a voracious appetite for potato leaves and quickly develops resistance to any chemicals used against it.

And a final example: the American bullfrog is considered one of the world’s most damaging invasives. The bullfrog does amazingly well in a variety of habitats –even artificial ones like millponds, irrigation ditches and reservoirs. Its incredible adaptability helps it spread and outcompete native frogs. Moreover, it has been transmitting a deadly fungus to previously unaffected populations of frogs, toads and salamanders.

Thanks to Lyle Bingham for information on the Eurasian collared dove. And to Ryan ODonnell for his audio recording from xeno-canto.org. For more information on the Eurasian collared dove and other invasive species go to www.wildaboututah.org.

For Wild About Utah, and the Quinney College of Natural Resouces, I’m Holly Strand.

Credits:

Theme: Courtesy & Copyright Don Anderson Leaping Lulu
1. Photographer Joy Viola, Northwestern University, Bugwood.org https://www.invasive.org/browse/detail.cfm?imgnum=5413582
2. USDA ARS Photo Unit, USDA Agricultural Research Service, Bugwood. https://www.insectimages.org/browse/detail.cfm?imgnum=1321015

Audio of Eurasian collared dove:
Ryan P. O’Donnell, XC98068. Accessible at www.xeno-canto.org/98068.
Creative Commons Attribution-NonCommercial-NoDerivs 2.5

Text & Voice: Stokes Nature Center: Holly Strand

Sources & Additional Reading:

Bingham, Lyle. 2009. The New Dove in the Neighborhood. Wild About Utah Program https://wildaboututah.org/the-new-dove-in-the-neighborhood/ October 8, 2009.

di Castri F. 1989. History of biological invasions with special emphasis on the Old World. In: Drake JA, Mooney HA, di CastriF, Groves RH, Kruger FJ, Rejma´nek M, Williamson M, eds. Biological invasions: a global perspective. Chichester, UK: John Wiley and Sons.

European Environment Agency, 2012. The impacts of invasive alien species in Europe EEA Technical report No. 16/2012. EEA, Copenhagen.

National Invasive Species Information Center (NISIC): Gateway to invasive species information; covering Federal, State, local, and international sources.
https://www.invasivespeciesinfo.gov/index.shtml

Simberloff, Daniel. 2013. Invasive Species: What Everyone Needs to Know. Oxford University Press

Medusahead Rye

Medusahead Rye Infestation
Courtesy and
Copyright © Steve Dewey

Flower
Courtesy and
Copyright © Steve Dewey

Plant
Courtesy and
Copyright © Steve Dewey

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

The New Dove in the Neighborhood

Eurasian Collared Dove
Note the black collar
and the broad square tail
Courtesy Stephen Peterson

Native Mourning Dove
Courtesy USFWS

During the winter after most doves have migrated, you may notice a dove foraging along the roadside or perched in a tree. A new species has arrived in our neighborhood, the Eurasian collared dove or Streptopelia decaocto, which has a distinctive black neck ring and a broad tail.

Originally found near the Bay of Bengal in Asia, this dove began its range expansion in the 1600’s. By 1900, it had made its way to Turkey, and by 2000 could be found as far north as the Arctic Circle in Scandinavia. Expansion into North America occurred in the early seventies when the collared dove appeared in the Bahamas. Since 1982, when first discovered in Florida, it has been gradually making its way north and west. Nineteen ninety-seven marked the first official report of Eurasian collared doves in Orem, Utah. Now they have spread throughout the state.

Eurasian collared doves join rock pigeons, the English sparrow, and the European starling as non-native birds that have expanded across the country. Experts attribute the success of Eurasian collared doves to the wide availability of seed offered by backyard bird feeders, as well as their ability to aggressively defend feeding areas. Some fear that they will cause territory or breeding problems for our native mourning dove, but so far there is no evidence to support this concern.

In an effort to reduce the number of Eurasian collared doves, the Utah DWR allows year-round harvesting. But be careful: don’t confuse this dove with the smaller mourning dove, which has a narrow, pointed tail and no ring on its neck. Eurasian collared doves have a distinct neck band and a broad, squared tail. Their calls also differ.

The mourning dove has the familiar melodic call:
[coo-ah cooo cooo coo]
[Kevin Colver, Songbirds of the Rocky Mountains
12 Mourning Dove]

Now listen to the Eurasian collared dove:
[“coo-coooo-coo”, “coo-coooo-coo”, “coo-coooo-coo”, “krreair”]
[Eurasian collared dove – From Kevin Colver’s private library
Two calls combined for this piece.]

The verdict is still out on the impact that the Eurasian collared dove will have on native species. In the mean time, let’s watch to see how this new dove adapts to the neighborhood and fits into the ecosystem.

Thank-you to Lyle Bingham of Bridgerland Audubon for writing this essay and to Kevin Colver for providing the recorded songs.

This is Linda Kervin for Bridgerland Audubon Society.

Credits:

Photos: Courtesy US Fish & Wildlife Service (USFWS) and Stephen Peterson, Bridgerland Audubon
Recordings: Kevin Colver, https://wildstore.wildsanctuary.com/collections/special-collections
Voice: Linda Kervin, Bridgerland Audubon
Text: Lyle Bingham, Bridgerland Audubon

Additional Reading:

Florida’s Introduced Birds: Eurasian collared-Dove (Streptopelia decaocto), Stephen A. Johnson and Gay Donaldson-Fortier, University of Florida IFAS Extension, WEC 256,https://edis.ifas.ufl.edu/pdffiles/UW/UW30100.pdf
Johnson, S.A. and *G. Donaldson-Fortier. 2009. Florida’s introduced birds: The Eurasian CollaredDove (Streptopelia decaocto). Florida Cooperative Extension Service Publication WEC 256 https://journals.flvc.org/edis/article/download/117916/115917

Tricky Bird IDs: Eurasian Collared-Dove and African Collared-Dove, Project FeederWatch, A Joint Project of the Cornell Lab of Ornithology and Bird Studies Canada, https://www.birds.cornell.edu/pfw/AboutBirdsandFeeding/EucdovRitdovID.htm

Romagosa, Christina Margarita. 2002. Eurasian Collared-Dove (Streptopelia decaocto), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online: https://bna.birds.cornell.edu/bna/species/630/articles/introduction

2009-2010 Upland Game Guidebook, Utah Division of Wildlife Resources, https://wildlife.utah.gov/guidebooks/2009-10_upland_game/2009-10_upland_game.pdf

Complete Birds of North America, ed. Jonathan Alderfer, National Geographic, 2006

Know Your Doves, Texas Parks & Wildlife Department, State of Texas, https://tpwd.texas.gov/education/hunter-education/know-your-doves