Ask Maine Audubon: Here’s How You Can Help Boost a Declining Firefly Population
Iconic pieces of a Maine summer evening: a late, wet sunset, a distant yodeling of a common loon, the flicker of fireflies. But the latter – as many people have noted and written to ask questions – is sadly becoming less and less common. It’s no surprise they’re dwindling – especially with recent stories of an “insect apocalypse” – but with so many people asking “where are the fireflies?” it seems like an easy topic to talk about here, especially because there are things we can all do to help.
First of all, it helps to know what the fireflies are doing. Fireflies, also known as lightning bugs, are insects, specifically beetles (Coleoptera) and not flies (Diptera). Fireflies are able to produce light, a process known as bioluminescence, through a chemical mixture in their abdomen. They use it as a form of communication, especially for mating. The male fireflies will fly around in the evening, flashing their lights, while the females watch from the ground. When a female sees a flash she likes (one of her own species), then she will return, the male will fly, and they will mate.
So one of the most important things, if you’re a mating firefly, is to have darkness. Unfortunately, darkness is less and less common. Studies show that light pollution is increasing by approximately 6% per year in North America, often from projectors, streetlights, advertisements or screen lighting. Where there is an increase in light pollution, there is a decrease in fireflies, simply because they cannot communicate effectively.
That doesn’t mean we have to get rid of all exterior lights, especially since many of them are there for safety reasons. Start by paying attention to the lights you have on, especially wide-spread spotlights at night, and consider turning them off when not in use. Even changing the type of fixture can make a huge difference. Use fixtures that direct light downward with shields, or look for ones called “full cutout”, with no light emitted above the horizontal. These are two great ways to limit or reduce light pollution.
The other important thing to change to help fireflies is our use of pesticides. Again, I want to acknowledge the safety issue here, as many people are concerned about ticks and other biting insects, but it’s important to realize that pesticides and insecticides are likely to have a far greater impact than these insects. “problems”. If you treat your garden for mosquitoes, you shouldn’t be surprised if you don’t see any fireflies.
One thing I learned recently is that firefly larvae love to eat slugs. More research needs to be done, but there is a correlation between areas that see a decrease in fireflies and an increase in slugs. Interestingly, I often get calls from people asking how to control slugs in their gardens, for which there are many safe and organic products to use. The active ingredient in many slug controls is acephate, which is a non-selective insecticide that kills any insect that comes in contact with it. So instead of looking for that “fix”, maybe turning off your lights, letting the grass grow a bit longer, and letting the fireflies do their thing will be the fix you need.
SONGBIRDS AT NIGHT
It’s actually already time to say goodbye to summer. It ends especially early if you’re a bird, as evidenced by the southbound shorebirds we saw passing on their fall migration a few weeks ago. They’ve got a long way to go, so they can’t waste any time, but for some Maine-breeding songbirds, they’ll try to squeeze in every summer they can. Although the nesting season is over for most birds, some still attempt the college experience. This led Susan and Jim Kanak of Wells to write and ask about the birds they hear singing at night, waking them up at 1am.
The likely singer, especially in southern Maine, would be a northern mockingbird. Some species, such as American robins, are remarkably early singers and often begin well before dusk. Mockingbirds, however, are known to sing their nocturnal songs for one particular reason: they are trying to attract a neighbor’s mate. We define songs as noises (mechanical or vocal) that are used to attract a mate or defend a territory, and late night thrashers are known to be unpaired males. Desperate times call for desperate measures, but at least it’s not John Cusack lambasting Peter Gabriel’s “In Your Eyes.”
The other cool nighttime songs you’ll probably hear come from two warblers. Masked warblers and forked birds both have complex songs, performed as part of an air show, which they perform at night. Instead of the Masked Warbler’s “witchcraft-witchcraft-witchcraft” or the antbird’s “teacher-teacher-TEACHER” they tend to sprinkle a jumble of extra notes on either side of the song. It makes you wonder why they have this variation, but maybe the extra effort is what it takes to find a mate, and in the dark you don’t have to worry so much about predators. It’s not hard to anthropomorphize the birds and sympathize with the situation: it’s getting late (end of breeding season), the group is playing its last song (sing your complex song), and maybe a fun dance will help to find a mate.
Do you have any questions or topics for Doug that you would like him to address in future columns? E-mail [email protected] and visit maineaudubon.org to learn more about backyard birding, native plants, and Maine wildlife and habitat programs and events. Doug leads free birding walks on Thursday mornings, 7-9 a.m., at Gilsland Farm Audubon Sanctuary in Falmouth.
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