The European starling (Sturnus vulgaris) is a small passerine bird that is native to Europe and parts of Asia. It was introduced to North America in the late 1800s and has since become one of the most numerous and widespread birds on the continent. The starling’s aggressive behavior and ability to thrive in human-altered environments have made it a nuisance species that outcompetes many native bird species. As such, various control methods have been implemented in an attempt to manage starling populations and mitigate their negative impacts.
Why are European starlings considered a problem in North America?
European starlings are considered an invasive pest species in North America for several reasons:
- They are very aggressive and will force native cavity-nesting birds like bluebirds and woodpeckers out of nest sites. This competitive exclusion reduces reproductive success of native birds.
- Large flocks of starlings cause damage to crops by feeding on fruit, seeds, and sprouting plants. They can devour huge amounts of food at cattle feedlots as well.
- Their droppings are acidic and can accelerate deterioration of infrastructure. Large roosts cause unsanitary conditions underneath bridges, buildings, etc.
- Starlings are known carriers of diseases that can affect humans, livestock, and other wildlife.
- Their loud, constant vocalizations and murmurations (large flocks) are considered nuisances.
In summary, starlings are able to thrive at the expense of native species, causing ecological, agricultural, and property damage. Controlling their populations is important to reduce these negative impacts.
When were starlings introduced to North America?
European starlings were first introduced to North America in 1890-1891 by Eugene Schieffelin, a wealthy drug manufacturer from New York. He was the chairman of the American Acclimatization Society and was intent on introducing all the birds mentioned in Shakespeare’s works into North America.
Schieffelin released approximately 100 starlings in New York’s Central Park in 1890 and 1891. He introduced another 40 birds in 1892. The starling population grew exponentially from these small introductions. By 1942, the starling population in North America numbered approximately 13 million birds. As of 2007, the North American population was estimated to be around 200 million birds occupying an area of over 7 million square kilometers.
So in the span of about 100 years, starlings went from a few dozen individuals to one of the most abundant bird species on the continent due to their aggressive spread and ability to thrive in human-altered habitats. This rapid population growth highlights the invasive potential of introduced species.
What methods have been used to control starling populations?
Many techniques have been implemented over the years in an effort to reduce starling populations and control their spread in North America:
Culling/lethal control
- Shooting – Allowed with proper permits, shooting is often used to control populations at feedlots, orchards, and other agricultural operations.
- Toxic perches – These are perches treated with a sticky substance containing a toxic pesticide. Birds that land on the perches receive a lethal dose.
- Avicide sprays – Pesticide sprays (like Starlicide) are applied to kill starlings in roosting areas.
- Trapping – Both live and lethal traps have been utilized. Live traps allow for relocation, while lethal traps euthanize the birds.
Nest/egg control
- Oiling eggs – Applying food grade corn oil to eggs prevents them from hatching.
- Decoy eggs – Placing fake or hollow eggs in nests prevents real eggs from being laid.
- Nest removal/exclusion – Physically removing nesting sites forces birds to relocate.
Habitat modification
- Exclusion netting – Netting buildings, overpasses, etc. prevents roosting.
- Porcupine wire – Spiked wire installed on ledges deters landing/roosting.
- Population limiting nest boxes – Artificial next boxes allow control over nest sites.
Behavioral control
- Auditory deterrents – Devices like propane cannons, ultrasonic emitters, etc. that emit loud noises to scare birds away.
- Visual repellents – Scarecrows, predator decoys (like fake owls/hawks), flashing lights, lasers, etc.
- Falconry – Trained hawks and falcons are used to scare/chase unwanted flocks of starlings.
Chemical repellents
- Avitrol – Causes anxiety/disorientation in birds that ingest treated bait, frightening flocks away.
- Methyl anthranilate – Artificial grape flavoring sprayed over areas acts as a taste deterrent.
How effective have control efforts been?
While small-scale localized population control has been achieved through trapping, shooting, and poisoning programs, most experts agree that complete eradication of starlings in North America is unlikely. Lethal control methods can temporarily suppress local populations, but surrounding starlings quickly repopulate areas. For example, a pesticide spray at a single roost site in the 1960s killed millions of birds, but the overall population was not decimated.
The European starling has exhibited an incredible ability to adapt and thrive across diverse habitats over the past century. Widespread control programs are costly, time consuming, and require constant upkeep. Birds must be killed faster than they can reproduce and immigrate into controlled areas. Public support for large-scale lethal programs has also waned in recent decades.
As such, contemporary management strategies focus more on localized control and preventing establishment of new colonies rather than complete extermination. An integrated pest management approach using multiple techniques like nest control, habitat modification, and repellents to mitigate specific conflicts is now considered more realistic than elimination of the species altogether. But the European starling remains numerous across North America due to its tenacity and highly effective invasion of the continent.
What are some current policies regarding starlings in North America?
The main policies and regulations regarding European starlings in North America are:
Federal laws
- Migratory Bird Treaty Act – Protects most native bird species, but starlings are excluded as a non-native pest species.
- Federal Insecticide, Fungicide and Rodenticide Act – Regulates pesticide use for starling control.
State laws
- Classified as non-game, exotic, or nuisance species in most states.
- No closed hunting season, bag limits, or possession limits.
- Depredation permits required for control activities like trapping, shooting, or poisoning.
Local ordinances
- Cities and municipalities may have additional restrictions on control methods.
- Noise ordinances may prohibit certain hazing activities in some areas.
In general, starlings lack legal protection and are exempted from regulations protecting native species. State wildlife agencies and the USDA Wildlife Services program are primarily responsible for management policies. Efforts focus on accommodating control activities while minimizing environmental and public health risks.
What are some promising new methods for starling control?
Researchers and wildlife managers continue exploring new techniques to improve starling control. Some promising experimental methods include:
Reproductive inhibitors
Chemical compounds like nicarbazin, which temporarily sterilize birds, have shown potential to humanely reduce populations when administered through treated bait. More research is needed to mitigate non-target hazards before regulators approve these compounds.
Auto-reset traps
Traps have been developed that can repeatedly catch and lethally dispatch birds without needing constant human resetting. These could allow sustained trapping pressure without extensive labor costs.
Nest Limiting Devices (NLDs)
Specially designed nest boxes have a rear-access panel that allows managers to remove nests and eggs, limiting reproduction. Installing networks of NLDs shows promise for local population control.
Laser dispersal systems
Low-power pulsing lasers can repel nuisance flocks without harming the birds. Laser systems mounted on vehicles allow efficient hazing of roosts and large aggregations.
Drones
Unmanned aerial vehicles equipped with speakers or lasers provide new options for remotely disturbing bird flocks and driving them away from problem sites.
Conclusion
In conclusion, introduced European starlings pose ongoing economic, ecological, and social conflicts across North America due to their rapid spread and invasive impacts. Attempts to completely eradicate the species have so far failed, but integrated management programs using lethal control, nest disruption, repellents, and exclusion can mitigate local nuisance issues and reduce environmental damage. Researchers continue developing promising new techniques, but starlings will likely remain a prevalent invasive species on the continent into the foreseeable future. Going forward, the most realistic approach relies on persistent monitoring and localized control to balance the needs of humans, agriculture, and native wildlife threatened by invasive starlings.
