The Eurasian Collared-Dove Story

Throughout human history, we have a tendency to “revamp” the natural ecosystems in which we touch. Usually, this ends in direct destruction or complete alteration. However, there are a few examples in which our change to natural ecosystems may not be so direct, yet still pose significant problems.

Such is the case with species introduction. Whether it is the release of non-native domestic cats, brown tree snakes, European Starlings, House Sparrows or brown rats onto islands and new worlds, the consequences still echoes after many decades and still potentially continue to diffuse into relatively recent times.

Of course, there are some seemingly less “undesirable” escapees within the world. A quick trip to the subtropical cities of Florida may yield exotic parrots, finches and the like thriving within a busy metropolis. Similar, on the other coast, the mild Mediterranean clime in California allows for the survival of similar birds. These seemingly beautiful organisms, etching a lifestyle in the warm climate, appear almost harmless to native environments. And perhaps, that is indeed sometimes the case for a few species. However, the spread in range of other species, such as the European Starling, has had a statistically significant effect on some native species’ populations. This is most notable in woodpeckers and other cavity nesting birds, which are sometimes outcompeted by the more aggressive starlings.

But, this story isn’t about the plight of the woodpeckers or the rise of the European Starling. Instead, it is about another great disperser – the Eurasian Collared-Dove.

In the late 19th Century, this dove was only breeding in temperate areas of Asia, with some populations reaching the more subtropical locations. From there, it spread into Europe during the 20th Century, reaching the Eastern parts of the continent in the early quarter of the Century. By the end of the Second World War in the mid-1940s, it had reached as far West as Germany. Then, it only took a little less than ten years to reach Britain and another few years to reach Ireland. Soon, its originally Asiatic range has expanded as far as some of the Nordic Islands. Of course, being the disperser that it is, it continued to expand in the Old World, reaching as far as Northern China, the Urals and even almost North to the Arctic Circle in Scandinavia.

For most animals, this feat would most likely reach an end right there…but that was just the end of the beginning.

In the early 1970’s, a few dozen Eurasian Collard-Doves escaped in the Bahamas. From there, they made the short hop over to Florida…and a new story began.

In North America, the Eurasian Collared-Dove made expansions at rates more than twice of the rates in Europe. At the start of the 21st Century, the dove was still mostly restricted to Florida and part of the Southeast. However, isolated populations soon began appearing around urbanized areas in the Midwest and the West, including as far as California. These populations expanded in size, joined other populations, and eventually spread throughout much of the United States. By 2015, the species has conquered much of the American West, reaching into British Columbia and Alberta…and individuals have now begun showing up in Alaska!

Expansion Map: http://ken-cdn.com/sites/default/files/imagecache/superphoto/14385835.jpg

Over the last decade, however, expansions in the Northeastern part of the United States have been relatively mild compared to the West. But in 2016, it isn’t extremely rare to see this species in places as far as Ohio and Delaware. In places such as New England, though, the species is still more or less vagrant only.

The bigger question, of course, is whether the species has had any negative impacts on native bird species. So far, the research data expresses that there is relatively little effect on native bird populations. However, due to its competitive and dispersive nature, populations are and still should be closely monitored for explosive growth. Thankfully, in some areas, the species apparently has already reached carrying capacity (such as Florida) and growth trends have seemingly plateaued.

So ends the story of the mighty Eurasian Collared-Dove. And as with its expansion in Europe, this ending may simply be the end of another beginning. Now, across suburban and urban areas of North America, the cooing of native Mourning Doves have been joined by a new invader. Perhaps it is an invader which has low impact. Or, perhaps its impacts just have not been quantified. Whatever the case, as humankind alters the environments around us, species will often fall. But within the initiation of the Anthropocene, a few hardy survivors may rise…for better or worse.

Sources:

Romagosa, C. M. 2002. . Eurasian Collared-Dove (Streptopelia decaocto). In The Birds of North America, No. 630 (A. Poole and F. Gill, eds.). The Birds of North America Online, Ithaca, New York.

Ehrlich, P. R., D. S. Dobkin, and D. Wheye. 1988. The Birder’s Handbook. Simon & Schuster Inc., New York.

North American Bird Conservation Initiative. 2016. The State of North America’s Birds 2016. Environment and Climate Change Canada: Ottawa, Ontario.

Partners in Flight. 2012. Species assessment database.

Sibley, D. A. 2000. The Sibley Guide to Birds. Alfred A. Knopf, New York

USGS Patuxent Wildlife Research Center. 2016. Longevity Records of North American Birds.

USGS Patuxent Wildlife Research Center. 2015. North American Breeding Bird Survey 1966–2015 Analysis.