Attached is what happens when western bluebirds nest in a pesticide-free garden like The Gardens at Heather Farm in Walnut Creek, CA. There is such an abundance of insects to feed young, the parents have to take turns to get into the nest box as they are catching insects so quickly. The flight to catch insects is less than 100 feet from the box into the gardens.
Brian, Walnut Creek, California
Down with pesticides … UP with bluebirds! Thanks, Brian! /Gary