The 2024 firefly season is over, and the results of season 7 show a continuing downward trend. I started monitoring fireflies at my parents' house during the summer of 2018, counting the number of flashes seen in 3 separate 10 second periods. I spaced my observation periods in 10 minute intervals, each with deepening darkness. Season 3, in 2020, was the highest total count with 708 flashes counted. Every season since then has seen totals lower than the previous.
Generally, firefly populations, like other insects, are decreasing. Reasons for this include habitat loss and degradation, pesticide use, and increased light pollution. Of course, local conditions will drive population trends in different areas. What caused my population to decrease is unknown, although cooler than usual spring temperatures could contribute.
From 2022 to 2023, there was a 25% decrease in number of flashes. Naturally, I was very curious as to whether or not the population would rebound in 2024, or even remain steady. Sadly, the numbers got worse. In 2024 the count was only 276, a decrease of another 26% on top of the 2023 decrease. That's a decrease of over 60% of the peak in 2020.
The charts below show firefly activity annually by daily flashes and annually by total flashes per year. You can see peak activity in late June and early July until 2023. 2023 peaked late and 2024 peak. Both years peaked at a rate lower than previous years.
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