The Eastern Bluebird was one of Virginia’s most common songbirds 100 years ago. but their numbers sharply declined due to environmental factors and development. Harsh winters, urban sprawl, lack of dead trees or snags, invasive house sparrow, a decline in winter food (native berries), and pesticides and herbicides like glyphosate which can kill bluebirds very quickly.
Thanks to conservation efforts establishing and monitoring bluebird nestboxes, their numbers are up. Other native small cavity nesting birds such as chickadee, titmouse, nuthatch, tree swallow, and house wren benefit from nest boxes as well.
By supervising nestboxes, monitors detect problems early and provide a greater chance of survival. Predator guards minimize the chance that snakes, squirrels, raccoons, large birds, and cats will prey on the eggs and nestlings. Monitors also look for signs of house sparrow nesting, ants, blowflies, and wasps and use remedies to discourage them.