To my mind, one of the most interesting has been the dramatic spread of the non-native Eurasian collared dove across North America.
The GBBC asks citizen birders to watch an area for at least twenty minutes sometime during a four-day period in mid-February (this year’s count concluded yesterday), and record the birds they see.
Just ten years ago, seeing a Eurasian collared dove would have been a novelty. No more: the doves are now commonly reported by birders in most of the United States.
In the 1970s, the Eurasian collared dove was introduced to the Bahamas. By the early 1980s, the non-native birds made their way to South Florida, where they established populations. Then they began spreading north and west.
Their range appears to have expanded slowly at first. A look at GBBC reports from 1998 show a lot of sightings in Florida, with some birds reported in Texas, Alabama and Arkansas.
By 2001, the doves reached California.
Last year’s bird count results showed the Eurasian collared dove had colonized much of the country. It has not (yet) been reported in New England, but it has reached as far north as Alaska.
In my state of Idaho, the doves were first recorded in 2005 by two backyard birders. In subsequent years, the bird was commonly reported in Idaho’s eastern corners. Last year, 132 GBBC participants reported 719 doves throughout the state.
I saw my first Eurasian collared dove in our backyard in 2008 – a banded bird that may have been an escaped pet. Last year, I began seeing the doves hanging around our neighborhood. This year was the first that I noted the species during my own participation in the Great Backyard Bird Count.
What’s going on here? Should conservationists be concerned about this spread?
Unlike some dove species, Eurasian collared doves aren’t migratory. However, they do readily expand into new suitable habitat. In fact, in their native Asia, Eurasian collared doves have been rapidly expanding their range as well – colonizing new countries every year.
The dove is one of those species that adapts well to humanity. The trees, power lines and bird feeders of suburbia provide perfect habitat. The Eurasian collared dove is almost always seen near homes and farms, not unbroken forest or prairie.
Research indicates it is not adversely affecting native mourning doves or other birds. It may simply be filling a new habitat niche created by suburban habitat. But it is still early in the spread.
Could Eurasian collared doves become an invasive threat? That remains to be seen.
Citizen science projects like the GBBC and another citizen initiative, Project FeederWatch, will help scientists continue to track the spread and impacts of the species. It will be interesting to learn what this year’s count found about Eurasian collared doves. If past years are any indication, their populations will likely have grown and spread into new areas of the country.