HouseWrens are small, native, brown, insect-eating birds with a cheerful song. They also have a reputation as being territorial during nesting season to help reduce competition. Unfortunately some wrens are known to destroy other cavity nest's (bluebirds, chickadees or even other wrens) by piercing holes in the middle of their eggs.
A House Wren weighs about as much as two quarters, is still able to pierce and remove a rival’s egg or even pull an entire nest out of a bird house. This is not the case with all wrens. With proper house placement and plenty of food available, most wrens will coexist with other birds peacefully.
Some research indicates that wrens destroy others nests only when they have their own nest within 20 to 30 feet of another nest. In that case, moving the nest box 100 yards away or less than 10 feet away may help.
In three studies, researchers found that males attacked eggs only before pairing up with a female, and females only attacked eggs only before the laying period. Once wren egg laying is complete, destructive tendencies may subside.
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