Predators & Competitors for
Nest Box

Nest boxes are sometimes occupied by species other than birds. Bees, mice, squirrels, and other wildlife can compete for box space with cavity nesting birds.

surprised, sweet, animal


  • Squirrels are the single biggest competitors to nest boxes. Squirrels are aggressive and the timing of their litters overlaps with breeding season of birds
  • Squirrels are more of an issue near human settlement and much less of an issue inside forests
  • Squirrels chew at entrance holes to damage boxes, making it easier for it and other predators to enter
  • For boxes with 30mm entrance diameter. Cut same sized hole, in a rectangular piece of sheet metal and attach it to front of box so that both holes line up. This will prevent the entry of squirrels.    
  • If a squirrel young is found while checking nest boxes it is best to leave it alone till the breeding attempt is over to clean out the box


  • Rats are usually not as serious a problem as squirrels. 
  • Rats occupy nest boxes for breeding which coincides with the breeding season of birds. Best to leave it alone and clean box after breeding is over
  • Rats can also occupy nest boxes for resting during winter months in which case it can be cleaned out before breeding season.
  • Rats and squirrels can be prevented from occupying the nest box by covering the entrance holes with 1mm metal sheet (GI or aluminum) after the breeding season.
bee, insect, sunflower
Bees and Wasps

Bees and Wasps

  • Bees are important pollinators but they do sometimes take up boxes
  • Bees and wasps rarely take over active bird nests, but are mostly found in empty boxes.
  • If bees have occupied the box than stay away from the box and dont disturb the bees. They usually will leave eventually in cooler weather
  • After bees have left clean out any combs or wax with soapy water. Use reusable gloves when handling boxes.
  • Wasps and bees can be prevented from establishing in a box by applying a thin layer of non stick cooking spray on the inside surface of the roof, thereby creating a slippery surface between the insects and roof of the box.


  • Ants can occupy boxes and build small ant colonies for nesting and residing. This is especially a problem during monsoon as ants try to find safe haven away from water.
  • Be careful with ant infested boxes. Ant spray can be used to kill ants. But be sure to come back a week later (following ant spray) to wipe the residues inside the box with wet cloth (use gloves).
fourmie, macro, insects
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Cats and monkeys

Cats and monkeys

  • Cats usually leap to the top of the box, sit on the roof and dip into entrance hole with their front paws to grab eggs or young. 
  • Extending the roof of the nest box beyond 3-4 inches from the front panel will make it difficult for these animals to reach the entrance hole from above.
  • Boxes needs to mounted at least 12 ft from ground to prevent cats from reaching top of the box in a single leap
  • Front patch of 2 to 2.5 cm thick will impede cats/monkeys from getting to eggs or chicks by preventing their paws or hand from reaching the bottom of the box. The hole on the patch needs to align with the box entrance hole.


  • Snakes can predate eggs and chicks from boxes and could be happening without our knowledge
  • If eggs or chicks go missing without a trace than possible it was swallowed by a snake
  • Avoid brush piles or decomposing garbage as these attract snakes
snake, reptile, animal