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Community Cats

The Vacuum Effect and Humane Deterrents

Vacuum Effect

If you are dealing with nuisance behaviors from community cats, you may be thinking, “Why can’t the cats just be relocated?” The answer is that this would cause what is known as the vacuum effect. The vacuum effect occurs when a group of community cats is removed from their outdoor home and relocated somewhere else. With that home now vacant, the space is free for another colony of cats to move in since the environment has proven to have adequate living conditions. The new colony that will move in could be unaltered, larger, and present more issues than you previously managed.

Humane Deterrents and TNVR

There is a much more effective and humane way to handle the community cat population, and that is through a TNVR (Trap-Neuter-Vaccinate-Return) program. Having the cats altered eliminates many nuisance behaviors associated with community cats, including population growth. Then, humane deterrents can be set up in your yard to discourage community cats from wanting to spend time there. This gives the colony the chance to relocate on their own.

Examples of humane deterrents:

  • Install motion-activated sprinklers.
  • Place chop sticks or plastic forks in your garden if cats are digging or lying there.
  • Neutralize urine smells with enzyme-based cleaners such as Nature’s Miracle or OdoBan.
  • Place rubber spikes along the top of your fence to discourage cats from jumping over. 
  • Use smells that repel cats: citrus, garlic, citronella, and eucalyptus.

More information on the vacuum effect can be found on the Alley Cat Allies page, The Vacuum Effect.

More information on Humane Deterrents can be found on the Alley Cat Allies page, Humane Deterrents.