Ontario Greenhouses Dim Lights to Save Migrating Birds

The purple and orange glow from Leamington, Ontario's massive greenhouses was so bright, people could see it from Detroit, 30 miles away. Now, a simple solution is helping birds and butterflies navigate safely while farmers keep growing fresh vegetables through Canadian winters.

Leamington sits along Lake Erie's northern shore, where it has earned the title of North America's greenhouse capital. Nearly 8 square kilometers of glass structures produce tomatoes, cucumbers, peppers, and strawberries year-round using powerful LED lights to sustain crops through dark winter months.

The industry exploded over the past decade, with satellite images showing dramatic expansion between 2015 and 2025. Those same lights that help plants grow, however, created an unexpected problem for nearby Point Pelee National Park, just six miles away.

The dagger-shaped peninsula serves as a critical rest stop for millions of migrating birds and monarch butterflies crossing Lake Erie. Artificial light at night disrupts their navigation systems, leaving exhausted travelers struggling to find their way.

In 2022, Leamington passed a bylaw requiring all greenhouses using supplemental lighting to install light-blocking curtains on walls and ceilings and close them at night. Farmers worried the regulations might hurt their ability to compete, but many discovered the curtains also helped control temperature and reduce energy costs.

Researchers from the University of Guelph measured sky brightness between fall 2022 and spring 2023 to see if the curtains worked. They found dramatic reductions in light pollution when greenhouse operators closed the curtains properly, though weather conditions like cloud cover and fog still affected overall brightness.

The Ripple Effect

This win shows how communities can balance economic growth with environmental protection when everyone works together. Leamington's greenhouse industry continues thriving, employing thousands and feeding millions across North America, while also safeguarding critical migration routes.

The curtain solution costs less than many expected and delivers benefits beyond wildlife protection. Farmers report lower heating bills and better crop control, proving that environmental solutions often create unexpected business advantages.

Other agricultural regions facing similar light pollution challenges are now studying Leamington's approach. What started as a local bylaw could influence how greenhouse operations worldwide think about nighttime lighting.

When spring arrives and millions of warblers, thrushes, and monarchs pass through Point Pelee, they'll find their ancient migration route a little easier to navigate, thanks to farmers willing to close the curtains.