Rodenticide’s Hidden Victims: How Poisoning Rodents Harms Owls and Raptors

Across our communities, many people rely on rodent poisons to control mice and rats around homes, barns, and businesses. What many do not realize is that these poisons often create collateral damage in the food web, harming the very wildlife that naturally helps keep rodent populations in balance.

Here in Lake County and across the Great Lakes region, owls and hawks play an important role in controlling rodent populations. But when rodents consume poison and are later eaten by predators, the toxins move up the food chain, a process known as secondary poisoning. The result can be devastating for birds of prey and other wildlife.

How Rodenticides Harm Raptors

Most rodent poisons used today are anticoagulant rodenticides, designed to prevent blood from clotting. Rodents that ingest these poisons may take several days to die, during which time they continue moving around and become easy prey for predators.

When a raptor eats a poisoned rodent, the toxin accumulates in its body. Because these chemicals can persist in tissues for long periods of time, predators may ingest poison repeatedly as they hunt.

For owls and hawks, this can lead to

• Internal bleeding

• Weakness and disorientation

• Increased vulnerability to vehicle strikes or other dangers

• Death from accumulated toxins

Research across North America has shown that a large percentage of tested raptors carry rodenticide residues in their bodies, including species commonly found in our region such as Great Horned Owls, Barred Owls, and Red tailed Hawks.

Nature’s Rodent Control Specialists

Ironically, the wildlife most affected by rodenticides are the same species that provide highly effective natural rodent control. Owls and hawks hunt rodents throughout the year and remove large numbers of mice, voles, and rats from the landscape.

For example

• Great Horned Owls frequently prey on rats, mice, and other small mammals in both rural and suburban areas.

• Barred Owls hunt rodents along forest edges and waterways.

• Red tailed Hawks, one of the most familiar raptors in Illinois, feed heavily on mice, voles, and other small mammals.

A single owl family raising chicks may consume hundreds of rodents in a breeding season, and hawks patrolling open fields and parks remove many more over time. When healthy raptor populations are present, they provide continuous, chemical free rodent control.

When Poison Replaces Predators

Using rodent poisons can unintentionally disrupt this natural system.

Rodenticides

• Kill rodents slowly, allowing them to be eaten by predators

• Remove natural predators through secondary poisoning

• May actually lead to increased rodent problems over time if predator populations decline

 Protecting birds of prey allows them to continue doing what they do best, keeping rodent populations in balance naturally.

 What You Can Do Instead

 Fortunately, there are safer and more effective ways to manage rodents without harming wildlife.

 Reduce attractants

• Store garbage and pet food securely.'

• Clean up spilled bird seed and eliminate outdoor food sources that attract rodents.

 Rodent proof buildings

• Seal gaps around foundations, vents, and doors.

• Repair damaged siding or roofing

• Keep firewood and debris away from structures.

Use traps instead of poison

• Snap traps can be effective when used properly.

• Avoid glue traps, which cause prolonged suffering and often capture nontarget animals.

 Support natural predators

• Protect habitat that supports owls and hawks.

• Maintain trees and natural areas where raptors can perch and hunt

• Encourage healthy ecosystems in parks, preserves, and neighborhoods.

Protecting Raptors in Lake County

 In Lake County, residents are fortunate to share the landscape with a remarkable diversity of birds of prey. From the calls of Great Horned Owls on winter nights to the soaring of Red tailed Hawks above open fields, these birds are an essential part of our local ecosystems.

When rodenticides are widely used, the consequences ripple through the food web and threaten these important predators.

 Reducing the use of rodent poisons is one of the simplest ways we can help protect raptors and support healthier ecosystems in our communities.

 How You Can Help

 Lake County Audubon Society encourages residents to choose wildlife safe rodent control methods and help spread awareness about the risks of rodenticides.

 You can help by

• Choosing poison free rodent control methods

• Sharing information about rodenticide impacts with neighbors and community groups

• Supporting local conservation efforts that protect raptors and their habitats

• Joining Lake County Audubon bird walks and programs to learn more about the incredible birds that share our region.

When we protect owls and hawks, we protect the natural systems that help keep our landscapes healthy and balanced.