The Eurasian collared dove (Streptopelia decaocto) is a medium sized dove species native to Europe and Asia. It has been introduced to many parts of North America, including the United States and Canada, over the past few decades. The Eurasian collared dove has had substantial ecological impacts in areas where it has been introduced. This article will provide an overview of the Eurasian collared dove, discuss how it was introduced to North America, and describe its effects on native ecosystems.
Overview of the Eurasian Collared Dove
The Eurasian collared dove is a member of the dove and pigeon family Columbidae. It is pale gray-buff to pinkish-gray overall with a distinctive black half collar on the nape of the neck. The tail feathers are white tipped. The legs and feet are pinkish red. It measures 25-29 cm in length with a wingspan around 47 cm.
The Eurasian collared dove originally evolved in warm temperate and subtropical zones from Europe to Japan. It thrives in open country with trees or scrub vegetation and readily adapts to human habitation in rural, suburban, and urban areas.
The Eurasian collared dove feeds primarily on seeds and cereal grains, but will also consume buds, shoots, and fruits. It usually forages on the ground in open areas like lawns, gardens, and agricultural fields. It breeds throughout the year if resources allow, producing multiple broods. The nest is a flimsy platform of twigs and stems placed in trees or shrubs.
Introduction to North America
The Eurasian collared dove was accidentally introduced to the Bahamas in the 1970s from pet escaped birds. From the Bahamas, it spread and established breeding populations in Florida by the 1980s. It then rapidly expanded its range across North America.
The Eurasian collared dove likely spread so quickly for a few key reasons:
- It thrives in human modified environments like suburbs and farms.
- It has a broad diet and high reproduction rate.
- There were no native look-alike species, so it faced no competition.
- It hitched rides along highways and other human transportation corridors.
Currently the Eurasian collared dove occurs across the southern United States from California to Florida. It ranges as far north as Alaska and all Canadian provinces. The map below shows its range expansion from 1980 to 2013.
Eurasian Collared Dove range expansion from 1980-2013
Impacts on Native Species
The introduction of the Eurasian collared dove has impacted native dove and bird species through competition for food and other resources. Below are some specific examples:
Competition with Mourning Doves
The mourning dove is a native North American dove species similar in size and ecology to the Eurasian collared dove. Studies have found mourning dove populations decline when Eurasian collared doves move into an area. The two species compete for food sources like seeds from bird feeders and agricultural grains. Eurasian collared doves tend to dominate in these conflicts due to their more aggressive behavior.
Threats to Songbirds
Eurasian collared doves may compete with native songbirds for tree cavities used for nesting sites. They have been observed displacing species like bluebirds and woodpeckers from nesting cavities. Their larger size and aggressive behavior gives them an advantage over the smaller songbirds.
Impacts on Native Predators
The Eurasian collared dove provides a new year round prey source that may subsidize predators like raptors and snakes. While this new food source may benefit the predators, it also may disrupt natural predator-prey dynamics. Certain predators may increase in number or alter their hunting habits in ways that more heavily impact native prey species.
Impacts on Human Structures and Agriculture
Aside from ecological impacts, the Eurasian collared dove causes issues for humans due its habit of nesting on man-made structures and foraging on agricultural crops.
Nesting on Buildings
Eurasian collared doves frequently nest on artificial structures near human habitation, such as telephone poles, signs, and building roofs and ledges. Their nests can clog gutters, short out electrical lines, or damage infrastructure. Their droppings also mess up outdoor areas below their nests or roosts.
Agricultural Damage
Foraging Eurasian collared doves may gather in large flocks on agricultural fields, especially during grain harvest. It is estimated they can consume 6-8% of grain crops at harvest time. They also will forage on sprouting crops earlier in the season, negatively impacting yields. The agricultural damage caused by Eurasian collared doves may have substantial economic impacts in heavily affected regions.
Disease Risks
Due to its close association with humans, the Eurasian collared dove may pose disease risks as it spreads. Below are some potential concerns.
Transmission of Parasites
Eurasian collared doves may carry exotic parasites like intestinal worms or mites that could spread to native birds and poultry. These novel parasites may severely impact species with no immunity.
Spread of Viruses
There is worry the Eurasian collared dove could spread viral diseases like West Nile virus more widely. West Nile is spread by mosquitoes from infected birds to humans and other animals. Eurasian collared doves are competent hosts for West Nile. Their increasing numbers could amplify disease spread.
Bacterial Infections
Eurasian collared doves may carry bacterial pathogens like Salmonella that can infect native species, poultry flocks, and humans. Their close affiliation with backyards, farms, and livestock operations increases opportunities for spread.
Management and Control
Given the negative impacts, there has been some efforts to control or manage Eurasian collared dove populations. However, reducing their numbers has proven very difficult across most of their introduced range. Possible management options include:
- Population control through trapping or hunting – This has a limited localized effect only.
- Removal of nests on structures – Can protect specific sites but not reduce overall populations.
- Limiting food sources like bird seed – May discourage doves from using backyard feeders but not much else.
- Chemical repellents – May discourage roosting on a specific structures but often ineffective.
More research is needed to find better Eurasian collared dove control methods that could work at a regional scale. In most areas, the Eurasian collared dove is here to stay as a permanent resident. Going forward, scientists must continue monitoring its ecological impacts.
Conclusion
The Eurasian collared dove has rapidly colonized North America thanks to its adaptability to human landscapes. While it provides some benefits as a new game and prey species, its impacts are primarily negative. It competes with native birds, damages infrastructure, spreads disease, and causes agricultural losses. Attempts to control Eurasian collared dove populations have largely failed. Scientists expect its numbers to continue increasing across its introduced range in the years to come. Careful management and more research on ecology and control methods will be needed to mitigate its impacts. Going forward, the Eurasian collared dove will remain a major invasive species of concern across North America.