Purple Martin Roosts of Nashville
A video of the roost descending into Trees right next to Broadway st.
Tracking Roost Size and Location with NEXRAD
Due to the local radar station being extremely close to Nashville, we were able to detect local movements of the roost site from year to year
Every autumn, hundreds of thousands of Purple martins claim Nashville as their home to kick off their migrations South. However, property owners and city officials have continuously attempted to deter the birds, due to the hundreds-of-thousands-worth of bird droppings on city streets each morning. Their deterrence efforts, primarily removing Trees after the migration ends, likely has negative effects on these birds. We look to radar to see if it can tell us if the roost has grown smaller in years following these disturbance events.
The figure above shows the change in the Nashville roost’s size (dark purple) relative to the populations of all roosts in the Nashville region (light purple). Dashed lines denote years where deterrence efforts occurred in the city.
The figure above shows the cumulative sizes of the Nashville roost over every season from 2013-2023. Notice how later years (lighter colors) are distinctly smaller than earlier years, indicating that the roost is shrinking year after year.