This past spring (1987), a friend related to me thathe had for several days noticed House Sparrows attempting to evict bluebirds from a box in his yard. Thinking the House Sparrows (Passer domesticus) may have started building a nest in the box, he opened it to remove the nest but instead found a badly injured female bluebird (Sialia sialis) slumped over in one comer. He brought
the bird to me about an hour later, but by that time it was already dead.