Eurasian collared doves have become the fastest avian invaders in histor
If you live in one of the towns in this region, you’ve seen them– cooing from telephone wires, fluttering down to drink from wet spots on lawns, sitting in the middle of streets. Eurasian collared doves are everywhere.
They’re so much a part of the landscape, it seems like they’ve been here forever. But in fact they arrived only about a decade ago – as part of the fastest invasion by a nonnative bird ever in the United States.
Today, Eurasian collared doves can be found all over the Four Corners.
“Their population really has exploded,” said Randy Hampton, statewide public information officer for Colorado Parks and Wildlife.
No Eurasian collared doves were recorded during the annual Christmas bird count conducted in Montezuma County until 2003, when two were noted. By 2009, the number sighted was up to 366. The number varies from year to year, as the bird count is just a sampling; in 2012 it was 127. But clearly the birds are here to stay.
“Eurasian collared doves have pretty much taken over the mourning-dove habitat,” said Cortez birder and naturalist Fred Blackburn.
The doves are the size of pigeons, about 15 inches long, with grayish-brown bodies and light gray underbellies and undertails. On their neck is a thin black band, which gives them their name. They have a monotonous coo – coo C O O – O O H coo, coo COOOOH coo, repeated over and over, with the one in the middle slightly longer, as if it had two syllables. They also sometimes make a harsh, bleating cry as they fly or land.
Their presence does not seem to be causing problems other than some concerns about how they might affect mourning doves and other native birds, but the rapidity of their spread is a rather amazing phenomenon.
Originally from India, they colonized Turkey and Europe in the 1800s and 1900s, according to published reports. Their arrival in America was the result of a pet-store burglary in the Bahamas in the 1970s in which some of the birds got loose and flew to Florida. They bred fast, and were well-established in the Southeast by the early 1980s. According to some reports, they may have initially been mistaken for a type of turtle dove, so biologists didn’t realize a new invasive species was spreading.
A 2010 article in the Billings Gazette describing their invasion of Montana said they arrived in that state in 1997 and by 2001 they were present in 31 of the Lower 48 states.
Today they have colonized the Pacific Northwest and Alaska. They are plentiful in Europe and thrive in a variety of climates, even north of the Arctic Circle in Norway.
“The first I knew of them, they were in Dove Creek,” Blackburn said. “Pretty soon they were here. They’re multiplying like lemmings. They’re better adaptable to a niche. There’s something here that has changed to make it attractive to them.”
Although biologists aren’t all sure what impact they may be having on the native mourning doves, Blackburn has no doubt.
“I don’t care what it says on the Internet. They ARE impacting mourning-dove populations, period.
“The mourning doves are gone from town [Cortez]. We used to have them nesting here. We’ve been watching it.”
He said one birder in Dolores shoos the Eurasians off her feeder. “As soon as she gets rid of them, the mourning doves come back. There are some reports where the two species are still mixed, but I’m pretty sure the mourning doves won’t be there much longer.”
According to a CPW brochure, mourning doves can be distinguished from Eurasians by their smaller size and more-pointed tail.
Mourning doves have a soft, haunting call, sort of a “cooAHoo, hoo hoo hoo.” The next-to-last hoo is shorter than the others.
Even if Eurasian doves have harmed native birds, they have been a boon to raptors such as eagles, hawks and falcons, according to Hampton.
Blackburn agreed. “They are servicing a lot of accipiters [smallish hawks], like Coopers and sharp-shinned hawks,” he said. “They’re taking the doves right off our deck here.”
Because Eurasian doves are classified as an invasive species and are not protected by the Migratory Bird Treaty Act, many states, including Colorado, have no limit on how many can be taken by hunters.
“We have special regulations in place to allow for more-liberal harvest,” Hampton said. “On general doves like mourning and white-winged, our season is Sept. 1 through Nov. 9.
“On the Eurasian collared doves, our season is year-round and statewide. The bag and possession limit on collared doves is unlimited.
“I think that shows from a management perspective we’re trying to get these things any way possible.”
Human hunters find the birds challenging to harvest, but tasty, according to an article by Scott Winston in Colorado Outdoors, a publication of CPW. “They taste just as good as mourning doves do,” Winston wrote. “With breast medallions half again larger than a mourning dove, they make for fine table fare.”
Eurasians are said to like farms where they can find spilled grain; one theory about their spread is that they followed railways where grain had been hauled.
According to Winston’s article, they are mainly ground foragers and, in addition to grain, will eat berries, plants and insects. They do not migrate, unlike mourning doves. They appear to flourish in humanmodified landscapes where there is water as well as food.
Some observers say their rapid growth may be attributable not so much to their crowding out other birds for food or territory, but to the fact that they can produce three or four broods a year, even more in warm climates.
The arrival of the Eurasian collared doves is just part of ongoing changes in the status of birds regionally. “You have species change all the time and out-compete other species,” Blackburn said.
Climate change is causing some birds to disappear from the area and others to appear, Blackburn said. Roadrunners have been sighted here in recent winters. “You can just generally say that you’re going to see a shift of animals north.”
For many birds, this year’s harsh summer and spring have taken a heavy toll, he said.
“The hummingbirds are suffering because nothing is blooming. They will decline, as well as any migratory birds that depend on that food source,” he said. “We’re seeing huge stresses on bird populations. We’re talking internationally, not just locally.”
But for some species, drought and heat have had benefits. With so many dead trees in the forests, woodpeckers and sapsuckers that like to seek insects in downed logs are doing well, he said. “With all the decaying wood, they’re in hog heaven.”
Mourning doves are banded in Colorado and other states as part of a program to monitor their status. Hunters should report banded mourning doves to the USGS bird banding lab, 800-327-BAND.
Project FeederWatch, a project of the Cornell Lab of Ornithology that monitors bird numbers across North America, is asking for people to help track the spread of the birds. For more information see http://projectfeederwatch. wordpress.com/2011/01/17/eurasian-collared-doves-conquering-america/.