Just because I haven't been writing this year doesn't mean I haven't been doing nothing this whole time. I completed my 4th season of Firefly Watch. This program is run by Massachusetts Audubon, but anyone anywhere can participate.
Observation protocols are simple. Count how many flashes you see in three separate ten second periods. I space mine ten minutes apart to get varying levels of darkness, starting just before sunset. We also record the flash pattern (single, double, or triple flash for instance), start and end times, wind, precipitation, and temperature. For good measure, I also record the colors of the flashes. I start at the end of May and depending on how long I keep seeing fireflies, I go until late August or early September. I use the same location every year to track the same population, and try to stick to the same dates every year.
2020 saw an increase over the previous year and 2019 saw a slight decrease, with 2018 being the initial and baseline year. 2021 was the first year to see a significant decline in the number of flashes. Not only was it lower than last year's total, it was the lowest of all four years. In 2020 I counted 708 flashes. In 2021 I counted 593, a 16% decrease.
I have no explanation for the drop. There were a few more rainy nights when I was doing observations in the previous years, and that may have grounded some of the fireflies. One night early in the season there was a thunderstorm with heavy rain and gusty wind and no one was flying that night. But in the previous three years I counted a grand total of 17 flashes on that date. While rain may account for some missing fireflies, it still leaves quite a void. Hopefully 2022 will see a rebound.
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| Year by year comparison of flash counts |
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| Flashes by date |
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