Photo © Jacqueline Bollinger

Blow Flies in Nest Boxes

Bird blow flies are an unwelcome blood-feeding parasite found in the nests of many species of birds. Their presence is occasionally blamed for nestling deaths, but there is little scientific evidence that they impact nestling survival, suggesting that their harmful effects are below a lethal threshold. In this month’s blog post, we explore what nest box stewards can or should do about them when monitoring nest boxes.