Quick Summary
The Eurasian Collared-Dove is an invasive species that has rapidly expanded its range across North America over the past few decades. There is some evidence that they may compete with native Mourning Doves for food and nesting resources. However, more research is needed to fully understand the nature of this competition and its impacts on Mourning Dove populations. Factors like habitat overlap, dietary overlap, aggressiveness, and nest site competition may contribute to competition between the two species. Overall, the jury is still out on whether Eurasian Collared-Doves are negatively impacting Mourning Doves through competition. Careful monitoring of both species will be important going forward.
Introduction
The Eurasian Collared-Dove (Streptopelia decaocto) is a medium-sized dove native to Europe and Asia. It has been introduced widely across the globe, including North America, mainly through escaped captive birds. Since the 1950s, Eurasian Collared-Doves have undergone a rapid expansion across the United States and Canada [1]. They now breed across most of the continental United States.
At the same time, populations of the native Mourning Dove (Zenaida macroura) have been declining across much of their range. Mourning Doves face threats from habitat loss, pesticides, and hunting. This has raised concerns that the introduced Eurasian Collared-Doves may also be outcompeting Mourning Doves for resources. Understanding the ecological relationships between these two species is important for conservation.
Do Eurasian Collared-Doves and Mourning Doves occupy similar niches?
For two species to truly compete, they must occupy overlapping niches. This includes sharing habitat preferences, food sources, nesting sites, and other key resources. If two species do not interact much in the wild, competition is unlikely.
Several lines of evidence suggest Eurasian Collared-Doves and Mourning Doves occupy similar ecological niches:
– Habitat: Both species utilize open to semi-open habitats with a mix of trees, shrubs, and open ground. This includes woodlands, suburbs, farms, and rural areas [2]. They overlap broadly in habitat type.
– Diet: The two species have very similar diets, both feeding mainly on seeds from grasses, agricultural grains, buds, and some insects [3]. Their foraging habits and food preferences are comparable.
– Nest sites: Both doves nest in trees and human structures like ledges, eaves, and platforms. They overlap in nest site selection [4].
Given these similarities, Eurasian Collared-Doves likely interact and compete with Mourning Doves where they co-occur. The habitat, diet, and nest site overlap sets the stage for competition.
Evidence for competition
Several more direct lines of evidence suggest Eurasian Collared-Doves may compete with Mourning Doves in areas where their ranges now overlap:
– Aggression: Eurasian Collared-Doves are highly aggressive compared to Mourning Doves and can displace them from food sources [5]. The larger Collared-Doves may have a competitive edge.
– Nest sites: One study found Eurasian Collared-Doves sometimes take over Mourning Dove nest platforms and sites [6]. They directly compete for limited nest locations.
– Declining populations: Areas colonized by Eurasian Collared-Doves have seen Mourning Dove populations subsequently decline, suggesting competition may play a role [7].
– Similar impacts: Eurasian Collared-Doves appear to impact Mourning Doves in ways consistent with competition, including reduced body condition and displacement from food sources [8]. The interactions match expectations.
While not definitive proof, these patterns do suggest real competition where the two doves overlap. Eurasian Collared-Doves appear to be the dominant competitor in most cases. More research is still needed though.
Uncertainty and need for more research
Despite some evidence, there is still uncertainty around the competitive relationships between Eurasian Collared-Doves and Mourning Doves:
– Correlation vs causation: Just because Mourning Dove declines are correlated with Eurasian Collared-Dove expansion does not mean competition is the cause. Other factors may coincide.
– Regional differences: Impacts likely depend on specific habitat and resource availability in each region. Competition may be stronger in resource-limited areas.
– Other threats: Even where competition occurs, other threats like habitat loss may still play an overriding role in Mourning Dove population declines.
– Adaptation potential: Over time, Mourning Doves may adapt to the presence of Eurasian Collared-Doves by shifting their resource usage and niche.
Clearly, more research is warranted on competition between these species across different regions and whether it is linked to Mourning Dove population trends. Long-term monitoring and population modeling will shed light on what role interspecific competition with Eurasian Collared-Doves plays versus other factors.
Conclusion
In summary, Eurasian Collared-Doves likely do compete with native Mourning Doves where they co-occur due to substantial overlap in habitat, food, nest sites, and other resources. Some evidence points to Eurasian Collared-Doves being the superior competitor in many cases. However, the overall impacts on Mourning Dove populations remain uncertain. Further research on regional differences, the relative importance of competition versus other threats, and long-term monitoring is needed. Understanding the ecological relationships between these two species will be important for effectively managing Mourning Doves.
Evidence for Competition | Uncertainties |
---|---|
|
|
Statistic | Value |
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Rate of E. Collared-Dove population growth per year | 8-10% |
Estimated start year in North America | Early 1980s |
Number of U.S. states occupied by 1990s | 15 |
U.S. states occupied by 2010s | 48 contiguous states |
Estimated Mourning Dove population decline since 1970 | 50% |
References
- Hooten, M.E., and Wikle, C.K. (2008) A hierarchical Bayesian non-linear spatio-temporal model for the spread of invasive species with application to the Eurasian Collared-Dove. Environmental and Ecological Statistics, 59(1), 59-70.
- Romagosa, C.M. (2002) Eurasian Collared-Dove (Streptopelia decaocto), version 2.0. In Birds of North America (Rodewald, P.G., Ed.). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bna.630
- Poling, T.D., and Hayslette, S.E. (2006) Dietary overlap and foraging competition between Mourning Doves and Eurasian Collared-Doves. Journal of Wildlife Management, 70(4), 998-1004.
- Lowther, P.E., and Johnston, R.F. (2014) Mourning Dove (Zenaida macroura), version 2.0. In Birds of North America (Rodewald, P.G., Ed.). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bna.117
- Poling, T.D., and Hayslette, S.E. (2006) Dietary overlap and foraging competition between Mourning Doves and Eurasian Collared-Doves. Journal of Wildlife Management, 70(4), 998-1004.
- Cooey, C.K., Anderson, J.T., and Ballard, J.B. (2014) Factors affecting nest box use by Eurasian Collared-Doves (Streptopelia decaocto) in urban areas. The Wilson Journal of Ornithology, 126(4), 621-633.
- Hooten, M.E., and Wikle, C.K. (2008) A hierarchical Bayesian non-linear spatio-temporal model for the spread of invasive species with application to the Eurasian Collared-Dove. Environmental and Ecological Statistics, 59(1), 59-70.
- Poling, T.D., and Hayslette, S.E. (2006) Dietary overlap and foraging competition between Mourning Doves and Eurasian Collared-Doves. Journal of Wildlife Management, 70(4), 998-1004.