Barn Swallow Projects

At our pilot study site, Patten Hill, the nesting Barn Swallow population increased from one pair in 2011 to 11 pairs in 2023. This increase occurred with habitat improvements: the creation of a mud source, the opening of large portions of the lower barn, including more open windows for access and egress, and the installation of clay nest ledges. Nest ledges are taken down and cleaned between broods and after the nesting season. The mud source is a shallow hole lined with lake liner and filled with natural clay and soil. It should be kept wet through the nesting season for nest building and repairs. Windows should be opened before swallows return and can be closed after they complete nesting. Note that when swallows are seeking nesting sites they will fly up if they see light above them, even if they have flown in through an lower opening. In these cases if an upper window is closed, they can get trapped. Make sure upper openings are either open, or that swallows cannot access them.