2025 has been a banner year for Common Terns breeding at Presqu’ile Provincial Park.  The park's Biodiversity team has ensured that there is now more protected nesting space than ever within predator exclusion grids. Working collaboratively, we have implemented further improvements to tern grids to deter predatory night herons, monitored tern productivity and improved our understanding of the long-term impacts of the grids on colony growth.

This year, terns began laying on May 10th and to date have laid 308 nests.  From these nests, almost 500 chicks have been successfully raised to fledging and are now dispersing from the island around the lake before they migrate southward for winter.   

For the first time, Highly Pathogenic Avian Influenza (HPAI) was detected in the colony. This was extremely concerning, since some European tern colonies have been devastated by this virus. As a result of our monitoring activities and knowledge of past virus events, we were able to quickly detect it and implement appropriate protocols to limit viral spread, including removing carcasses daily. Consequently, only 34 adults (5% of the colony) and very few chicks were killed. The colony continued to grow and had the highest fledgling production on record. 

We thank Friends of Presqu’ile for their support of Common Terns at Presqu’ile and the dedication of the park's bio team and all those who have supported this work to protect this unique and regionally important colony. Keep your eyes open for adult terns and their fledglings along the shorelines of the park!