By Laura Thipphawong
For years, the disturbing sight of dead birds littering Georgian Bay shorelines in the fall has been an unwelcome trend for residents and visitors, and especially for the native wildlife who are paying the ultimate price. The first reported case in Georgian Bay was in 2010, and then again in 2011, when a massive die-off was reported in late October, with over 6,000 dead birds scattered across Georgian Bay beaches near Wasaga throughout the course of a few days. This was the largest known bird die-off in Ontario since roughly 25,000 birds were found dead in Lake Erie a decade prior, and now, over the last few years, major die-off events have occurred in Georgian Bay with hundreds of bird deaths reported in 2021 and again in 2024. While testing is still underway for this year’s incidents, the cause of death is almost certainly type E botulism, as has been the case in previous years.
Experts believe that the reason for these outbreaks is two-fold: the rampant spread of botulism from invasive species – and the warmer waters, which provide an environment in which the invasive species can thrive. The invasive species in this case are the zebra and quagga mussels, and round goby.
Photos on the left and right courtesy of the All Too Clear filmmakers at Inspired Planet
The chain of events
The bacteria that cause type E botulism lives buried in the sediment of the lakebed, and is ingested during filtration by the large quantities of bottom-dwelling mussels.
The high volume of mussels supports the staple diet of round goby, a bottom-dwelling European fish (which entered North America via ship ballast around 1990) whose voracious eating habits and ability to spawn multiple times a year make them particularly difficult to manage as an invasive species.
When goby eat the botulism-laced mussels, they swim slowly and erratically, making them easy targets for birds, such as seagulls, loons, ducks, and cormorants. Round gobies thrive in warmer water, so as the lakes continue to rise in average yearly temperature, the goby will continue to increase the frequency of their spawning. Type E botulism also thrives in warmer conditions, accumulating during the summer, leading up to the die-offs in the fall.
It’s a shocking and upsetting trend that, unfortunately, is likely to become a yearly event if nothing is done to intervene. The consequences of unnatural climate change are all around us, and it’s up to each of us to take action. Help to end the massive die-offs in Georgian Bay by reducing your carbon footprint, voting for legislation that benefits rather than destroys the environment, and supporting your local organizations like Georgian Bay Forever, whose work on invasive species management and environmental conservation is more important now than ever.
What to do if you discover dead or distressed wildlife:
Keep your pets on a leash and do not let them touch dead birds or fish.
Do not handle the wildlife unless necessary. If moving a carcass is required, wear a mask, gloves, and eye protection, and double-bag the carcass.
Contact the Canadian Wildlife Health Cooperative (CWHC) if you find dead wildlife on Georgian Bay shores – 866-673-4781
Contact Shades of Hope Wildlife Refuge if you find dead wildlife near southeastern Georgian Bay – 705-437-4654
Contact the Ministry of Natural Resources and Forestry if you discover fish die-offs in Ontario – 1-800-667-1940
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