I have not sprayed my garden for bugs in 35 years. I put 25 bird houses around the garden area and back yard the birds eat all the bugs. I put several bird bath type containers of water in the garden so birds can drink water and not peck holes in my tomatoes to get a drink.
Wrens eat their body weight in bugs every day. You can attract a lot of Wrens if the houses are build the correct way and mounted the correct way and height. Birds like the house hanging from a wire over a tree limb rather than screwed ridged to the side of a tree or pole. Houses need to be 8 to 10 feet off the ground with the door facing east. Bottom of the house is made from 1x4 lumber cut in square that measure 3.5" x 3.5" square. Cut the corners off 3/4" so the floor has 4 air vents in the corner of the room. The door should be 7/8" x 3" wide 4" up from the floor measured on the inside. The left and right side wall should be cut 1/4" too short this makes another air vent under the eves of the roof. The point of the roof needs to be cut off 3/4" to make 2 more air vents. The roof needs to hang over the front and back 3/4" for a rain guard. The perch is a 1/2" diameter tree limb glued into a 1/2" hole 1" below the door.
The 3" wide entrance hole makes it easier for the birds to build a nest. It also allows 3 tiny hungry babies to look out to see when Mom is arriving with their next dinner.