Anti-rat tactics, like cats and poison, kill wildlife. What to do?

The First Line of Defense: Hygiene. Dispose of Food and Pet Waste properly.

Food correlates with rat populations: More food, more rats. “With less food available, females are able to produce fewer young, and if food is eliminated, the adult rats either move on or simply cease to reproduce,” says Larry Heaney, an expert on rodents (click for more details), and the Curator of Mammals, Field Museum of Natural History, Chicago.

What is wrong with Poison?

It doesn’t work, and the cost to birds and other wildlife is high. Adult rats learn quickly to avoid bait boxes. The poison kills birds - such as owls, hawks and eagles - and other wildlife when they eat poisoned rats. Also, chipmunks and other small mammals eat the poison and die.

“Adult rats are very wary of anything new in their environment. If one sees another rat (usually a young one) eat poison bait and soon die, they will never eat the poison bait. Given the very high rate of reproduction, quite a few babies can die and serve as a warning to others without causing much decline in the rat population, and new babies quickly take their places,” says Heaney.

Pest control companies and homeowners usually use anticoagulant pellets that prevent blood from clotting, and kill the rats. In common use now is a very toxic second generation of poison. This second-generation rodenticide kills fast but stays in animal tissues longer. So it is more likely to poison wildlife that eats the rat, and even the EPA has tried unsuccessfully to take action to limit its use.

To reduce the use of poisons, communities like Evanston are purchasing tanks of compressed Carbon Dioxide (CO2) to inject directly into rat burrows. CO2 puts the rats to sleep before suffocating them and can eliminate a large population of rats at one time without killing other wildlife.

What about Feral Cat Colonies?

Some neighborhoods and municipalities, including Chicago and in Evanston, are using feral cat colonies to try to control rats. Studies show that feral cats displace, but do not kill adult rats. Rats move away from feral cats, shifting the problem to a new neighborhood or block. Cats kill only baby rats, rather than the fast-breeding adults that need to be reduced to impact the rat population. There is another big problem with cats: they kill many, many songbirds. In fact cats are the third largest anthropogenic killer of wild birds after climate change and habitat loss.

Cat killing a Tennessee warbler. photo by Matt Igleski

Steps to Encourage in Your Community.

Advocate for these solutions:

Prioritize proper disposal of food and pet waste instead of poisons. Consider special containers for restaurant cooking oil.
Community walks with municipal officials to identify problem areas. See if cleanup solutions could fix the problem.
Provide residents with rodent and leak-resistant trash cans. Consider more secure public garbage cans in problem areas (e.g., not open-topped).
Consider more frequent garbage collection, especially in problem areas.
Carbon dioxide. Test compressed co2 to clear out rat burrows.
Plug rat holes and weed along foundations and alleys where there is evidence of rats. Note rats will harbor anywhere they can, even in concrete. So eliminating plantings should focus on areas where rats currently live.
Share the CAS infographic with municipal officials and community members

What can we do at Home to keep Rats Away?

Dispose of food and pet waste in closed, rat-proof garbage cans.
Get garbage cans repaired or replaced immediately if they have holes or are broken.
Encourage more frequent collection of garbage.
Compost properly: no oils or meat in compost bins.

What if we See Rats on our Property?

Take the steps above.
Remove seed and suet bird feeders.
Plug access holes in the building foundations, including your garage.

For More Info

 American Bird Conservancy, Trap, Neuter, Release

 PETA, Does TNR Save Cats?