Problems & SolutionsAnts in Nestboxes

Ants in Nestboxes

"sugar ants" in a birdhouse. Bet Zimmerman photo
I’m not sure what species these are – I call them “sugar ants.” They are unlikely to harm nestbox contents, but may swarm all over the box and your hand when disturbed. Click here for higher resolution photo: I occasionally find them in nests in CT.

QUICK TIPS:  For active nests, sprinkle cinnamon underneath and/or do a nest change.  Remove old nests, use ant bait at base of nest.

Ants sometimes “infest” nests in boxes. Fire Ants can be a serious problem, as they will kill and eat nestlings – Read More about Fire Ants. Other ant species may not harm eggs/young, but may pester them by crawling on their bodies. This can interfere with rest, and could potentially result in premature fledging.

To control crawling insects after the first egg is laid, try the following:

I’m not sure what species these are – I call these “sugar ants.” They are unlikely to harm nestbox contents, but may swarm all over the box and your hand when disturbed. Click here for higher resolution photo. I occasionally find them in nests in CT.

  • For an active nesting:
    • Lift nest with a spatula and generously sprinkle the floor with cinnamon (that you can buy at the Dollar Store.) Ants should be gone in 24 hours.
    • Consider a nest change.
    • Unhatched eggs occasionally break and attract eggs – DO NOT REMOVE UNHATCHED EGGS TOO EARLY though – wait at LEAST 72 hours after the last egg hatched – see more info.
  • Remove old nests immediately after babies fledge, as detritus and feces may attract ants.
  • Place a small moat around the bottom of the mounting pole (e.g., put a “Bundt” style baking pan down over the pole and fill with water.)
  • Ant Bait
    • Boric acid baits are excellent and extremely safe, according to Keith Kridler of Texas who regularly battles fire ants. The active ingredient that kills ants (and roaches) is the essential plant element Boron. It is safe for humans and warm-blooded creatures.
    • Amdro ant bait placed weekly in a.m. by base of pole.
    • Spinosad is an organic ant bait.
    • Make sure ant bait is fresh (one year max) and does not absorb other smells.
  • Dip Q-tips in an ant repellant called “Terro” and staple them to the outside bottom of the box, and tape a few to the pole.
    • It may be available at a feed store, nursery, or some hardware stores such as Ace, True Value or Aubuchon, or can be purchased online.
    • Wrap green garden tape around the mounting pole, right under the box, or UNDER the baffle and then apply the Tanglefoot to the tape (put tape on tightly so ants can’t crawl under it  More….) When the Tanglefoot loses its effectiveness, just cut the green tape off and remove it.
    • Be careful not to put it where a bird could come into contact with it as it is sticky and will be almost impossible to remove from the bird!
    • If you get it on your clothing a solvent (e.g., GO-JO cream available at Sam’s, or Citra-Solv) will remove it.
    • If Tanglefoot does get on a bird, call a rehabber or use mineral oil to dilute the tanglefoot. Then use soap (Dawn liquid detergent) and WARM water. Around the eyes do the same but with a Q-tip. Rinse thoroughly) (Do NOT use Tanglefoot Bird Repellant)
  • Grease (automotive or all purpose) is okay, but when the temperatures get hot the grease may run, whereas Tanglefoot will not. Vaseline or a mixture of turpentine and lithium grease may be painted in a 4″ wide ring around the mounting pole (directly under the nestbox, or if there is one, under the baffle, to prevent blue feathers from coming into contact.) It will harden in the sun, so reapply twice during nesting season. Dirt/vegetation stuck to grease will allow ants to cross.
  • Petroleum Jelly: Used in conjunction with a nest change, petroleum jelly can help control ants from climbing up your martin pole. Smearing a ring of petroleum jelly around your purple martin pole will stop ants from being able to climb up it immediately but you may have to check daily as some ants will persist and build a bridge over the ring of petroleum. Determining the source of the ants on the ground and the type of ants can help you form a permanent solution. Treat ant hills with any commercially available ant killer that is formulated for that type of ant. Use the insecticide per the recommendations of the manufacturer on the ant HILL (mound) only and not in the nests!
  • Herbal deterrents: (effectiveness?) Try putting a small amount of crushed sage or crushed peppermint leaves under the nest.

Related Information:

It is not enough to be busy. So are the ants. The question is: What are we busy about?
– Henry David Thoreau


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