The Eurasian Collared Dove (Streptopelia decaocto) is native to the Indian subcontinent but has undergone a massive global expansion. After establishing itself across Europe in the mid-20th century, the bird arrived in the Americas following an accidental release in the Bahamas during the 1970s. The species rapidly colonized the continental United States and Mexico, spreading at an exceptional rate. This explosive population growth and adaptability have transitioned the Eurasian Collared Dove from a curiosity to a widespread nuisance causing significant ecological and economic conflict.
Ecological Impact on Native Bird Species
The primary concern regarding the Eurasian Collared Dove involves aggressive competition with smaller, native species for limited resources, known as resource displacement. The Eurasian Collared Dove is larger and stockier than the native Mourning Dove (Zenaida macroura). Its assertive nature allows it to dominate food sources, frequently chasing away smaller birds like cardinals and jays, effectively monopolizing available sustenance at feeders and watering holes.
The dove’s exceptional reproductive capacity allows it to quickly increase population density. A pair can raise up to six broods annually, with the nesting cycle taking only around six weeks. This high-output breeding contrasts sharply with the slower reproductive rates of native dove species, enabling the invasive population to swell rapidly.
The doves are also known carriers of the parasite Trichomonas gallinae, which causes the fatal disease avian trichomonosis. While collared doves may be resistant, they transmit the parasite to native doves at shared feeding and bathing sites. They can also transmit the disease to raptors that prey on them.
Property Damage and Urban Nuisance
The Eurasian Collared Dove prefers nesting and roosting near human structures, resulting in daily annoyances and physical damage for property owners. The birds produce a monotonous, three-note “coo-coo-cook” call. This constant vocalization is often repeated incessantly, especially during the extended breeding season, becoming a significant noise pollutant in residential settings.
Physical damage is caused by the accumulation of feces in communal roosts. Droppings stain vehicles, walkways, and roofing materials, and the acidic waste accelerates the deterioration of building surfaces. The doves also build poor, bulky nests of loosely gathered twigs in inconvenient locations, such as rain gutters and air conditioning units. These nests frequently cause blockages in drainage and ventilation systems, leading to structural or mechanical issues.
Agricultural Losses and Grain Contamination
In agricultural areas, large flocks of Eurasian Collared Doves become an economic threat. The birds primarily consume seeds and grains, congregating in fields to feed directly on marketable crops such as corn, wheat, and sunflower. This consumption causes direct yield loss for farmers, particularly before and during harvest when grains are most accessible.
Beyond consumption, the birds create a serious contamination problem by roosting and foraging around stored grain. Facilities like feed mills and grain elevators attract hundreds of doves seeking easy access to food. Their droppings foul stored commodities, leading to spoilage and health risks if the contaminated grain is used for consumption. The presence of doves requires costly clean-up and disposal of the affected product.
Options for Managing Local Populations
Because the Eurasian Collared Dove is an introduced species, it is not protected under federal regulations like the Migratory Bird Treaty Act in the United States. This provides flexibility in management. In many jurisdictions, the birds can be humanely removed or hunted year-round without bag limits. Local ordinances regarding firearms must be verified before attempting lethal control.
Non-lethal methods focus on making properties less attractive and physically excluding the birds from problem areas.
Exclusion and Habitat Modification
Exclusionary tools like specialized bird netting or anti-perching spikes on ledges prevent the doves from landing and nesting on buildings. Habitat modification involves removing access to food and water sources, such as cleaning up spilled seed around feeders or removing standing water. Homeowners can use platform feeders, which the doves prefer, or switch to tube feeders that are more difficult for larger birds to access.
Deterrents
Auditory and visual deterrents, including specialized distress calls or reflective materials, can also be employed. These methods often require rotation and integration with physical measures to maintain effectiveness.