Starlings are small black birds that often congregate in large flocks. While starlings are visually interesting to observe, they can also become major pests for homeowners, farmers, and property managers. Their droppings are acidic and can damage buildings, vehicles, and machinery. Large flocks feeding on crops can cause significant economic losses. For these reasons, finding effective deterrents for starlings is an important wildlife management goal.
Why Are Starlings Considered Pests?
Starlings are an invasive species in North America, introduced from Europe in the 1890s. They spread rapidly across the continent and now number over 200 million birds. Their large flocks and aggressive behavior outcompete many native bird species.
Some key problems caused by large flocks of starlings include:
– Droppings – Starling droppings are acidic and can accelerate corrosion and deterioration of buildings, vehicles, machinery, and outdoor statues. Large amounts of droppings accumulate under popular roosting sites.
– Noise – The loud, constant noise from flocks can be a nuisance to businesses and residents.
– Food contamination – Starlings may contaminate food and water sources at farms and livestock facilities. Their droppings and feathers can contaminate feed and water troughs.
– Crop damage – Starlings will feed on ripening fruit crops, freshly planted seeds, sprouting crops, and livestock feed. Their sheer numbers can decimate crops and cause major economic losses.
– Health hazards – Starlings can spread diseases in their droppings including histoplasmosis, salmonella, transmissible gastroenteritis, cryptococcosis, and more. Droppings may contaminate soil and water.
– Aviation hazards – Starling flocks are hazardous to aircraft. Their bodies can get sucked into jet engines causing engine failure.
Common Starling Roosting and Feeding Behaviors
To deter starlings effectively, it helps to understand their daily routines and behaviors.
During the day, starlings form large foraging flocks that fly out from their roosting sites to feed. They prefer open habitats such as lawns, pastures, farms, and parks where they forage on insects, fruit, grains, seeds, and human food waste. Towards dusk, they start gathering at their traditional roosting sites which may include trees, dense vegetation, warehouses, barns, bridges, signs, eaves, and other sheltered structures.
Roosts are often located close to abundant food and water sources. Starlings jostle over the best protected spots and usually roost in tight groups for warmth and safety from predators. Just before dawn, starlings leave the roost en masse in a loud swarm to forage again for the day. Roosting sites, feeding areas, and flight paths are traditional and may be used for months or years unless the birds are deliberately dispersed.
Understanding this daily behavior cycle helps optimize the timing and placement of deterrents and dispersal techniques.
Passive Starling Deterrents
Passive deterrents involve modifying the physical environment to make it less attractive or accessible to starlings. Since starlings seek protected roosting spots and abundant food sources, passive deterrents aim to deprive them of these.
Exclusion
Blocking starlings from accessing their sheltered roosting spots is very effective. Install plastic or nylon netting over eaves, rafters, signs, ledges, or other roosting sites. Mesh openings should be less than 1 inch to exclude starlings. Solid metal sheeting or coyote rollers can also be installed on ledges or roof beams. Hang flexible PVC strips in openings to allow humans to pass through but block birds.
Remove Food and Water
Eliminate any food sources starlings may use near their roosting sites. Clear fallen fruit from orchards, contain livestock feed, and manage dumpsters with tight fitting lids. Use bird feeders with weight-activated perches that only allow small birds to access food. Remove sources of open water like leaky taps or clogged gutters where starlings may drink and bathe. Installing water recirculation systems on ponds or water features can also deter starlings.
Modify Roosting Sites
Pruning trees and shrubs to open up the canopy and eliminate dense tangles deters roosting. Removing taller trees forces birds to roost lower where they are more vulnerable to predators. Installing roughened anti-perching strips or netting on ledges and roof beams obstructs comfortable roosting. Using tactile repellents like sticky gels or spike strips can also make surfaces uncomfortable for birds.
Passive Starling Deterrents | Examples |
---|---|
Exclusion | Netting, metal sheeting, PVC strips, rollers |
Remove food and water | Clean up fruit, contain feed, manage dumpsters, recirculate water |
Modify roosting sites | Prune vegetation, remove tall trees, install perching deterrents |
Active Starling Dispersal
When passive deterrents alone are ineffective, active dispersal techniques can be used to scare starlings away from problem sites. Combining active and passive techniques often gives the best results in the long term by deterring starlings and excluding them from returning.
Visual and Audio Frightening Devices
– Predator decoys – Decoys or silhouettes of predators like hawks and owls can frighten starlings. Move them regularly so birds don’t habituate.
– Flashing lights – Strategically placed strobe lights, laser lights, or blinking LEDs disturb starlings. Motion activated lights work best.
– Automated scarecrow devices – Propane cannons, bird bangers, or distress call systems scare birds when activated by motion sensors or timers.
– Audio deterrents – Broadcasting starling alarm and distress calls, ultrasonic noise, or loud music creates an unpleasant environment.
Chemical Bird Repellents
Non-toxic methyl anthranilate aerosols cause birds discomfort and repel them from treated areas. Apply directly on roosts or mix with water and spray where starlings congregate. The effects are temporary so reapply every 3-4 days.
Hazing and Harassment
Actively scaring starlings by making loud noises, waving arms, spraying water, or using pyrotechnics when they first arrive at roosts in the evening helps deter them from settling in. Persistently scaring them off their roosts for three to four consecutive nights when they first establish roosting patterns in fall can re-train them to find alternative sites.
Active Starling Dispersal | Examples |
---|---|
Visual and audio frightening devices | Predator decoys, flashing lights, scarecrow devices, distress calls |
Chemical repellents | Methyl anthranilate sprays |
Hazing and harassment | Loud noises, water spray, pyrotechnics |
Conclusion
Deterring problematic flocks of starlings requires an integrated pest management approach combining passive deterrents and active dispersal. Installing physical barriers provides long term exclusion, while harassment and scaring reinforces the message that starlings are not welcome.
Key strategies include:
– Block access to roosting and nesting sites with nets, sheeting, coils, strips, and pruning.
– Manage food, water, and open garbage to eliminate resources.
– Use frightening devices and sound deterrents. Vary locations and move often.
– Apply methyl anthranilate repellents. Reapply frequently.
– Actively haze birds by making loud disruptions when they first arrive at roosts.
– Be persistent and use multiple integrated techniques to deter starlings successfully over the long term. Follow legal guidelines and seek permits if required.
Following these best practices provides an effective, environmentally safe approach to deterring destructive flocks of starlings while minimizing risks to other wildlife. A committed integrated pest management program can successfully resolve starling problems.