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| Spicebush Swallowtail nectaring on milkweed at Huntley Meadows, in Alexandria, VA |
Today's post was originally published for the butterfly survey project I run, over at
Woodend Sanctuary in Chevy Chase, Maryland. Since the weather has been nice and warm for several days now, we're starting to see quite a bit of butterfly activity. There are hundreds of different kinds of butterflies, of many shapes and sizes. It can seem kind of bewildering at first when you're learning how to identify them. Over the years I've found several strategies can help you make sense of it all, though-- in particular learning what you need to look for. So to help you out, here is my general strategy on how to butterfly an unfamiliar butterfly in the field.
Size
The first observation to make when you see a new butterfly is its relative size. Our largest butterflies, swallowtails, tend to be about 3 or 4 inches across. Our smallest, blues and azures, are barely an inch across. The rest are somewhere in between. A birding trick that also works for butterflies is to use a familiar butterfly to help you remember an unfamiliar butterfly's size. Cabbage Whites are probably our most ubiquitous butterfly, and their medium size make them a great comparison.
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| Cabbage Whites are about 3 inches across when their wings are open, or 1.5 inches when their wings are closed like in this photo. | | |
Color(s)
Next you want to check out the main color of the butterfly. If it’s flying you may only get a general impression, e.g. darkish, or somewhere between white and yellow. Don't worry too much if you can't see details just yet.
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| A Peck's Skipper was posing nicely when I went to take the shot, but then of course took off as soon as I pressed the shutter release. But if this was what I actually saw in the field, I could guess it was a skipper because of the small size and the orange-and-black coloring. |
Flight Style
While the butterfly is in flight (which it almost certainly is), take a look at *how* it flies. Some kinds of butterflies have easily recognizable flight patterns that can help you identify them, especially in combination with their general size.
Blues and Hairstreaks fly very erratically, switching directions every few seconds.
Swallowtails and Fritillaries fly more strongly and steadily than the smaller Blues & Hairstreaks.
Satyrs and Browns have a distinct “bouncy” style of flight—that is, veering up for a ways and then back down, then up again.
Once the butterfly finally comes to a rest, perhaps on a flower to nectar or on a sunny leaf to bask, you should look more closely at its colors and markings. The exact shape, size, and location of markings (stripes, spots, and /splotches/) varies from species to species. Some species that look relatively similar, like Spicebush and Pipevine Swallowtails, are easy to tell apart when you know which field marks are different. Pipevine Swallowtails have big round orange spots on the underside of their hindwings (the right-hand image below), while Spicebush Swallowtails’ spots are smaller and differently shaped.
You should remember that butterflies often have different markings on their upper (dorsal) side than on their under (ventral) side. Also take note of whether the markings are on the forewings (the pair of wings closest to the butterfly’s head) or the hindwings (closest to their abdomen). This will be important when you're reading descriptions of possible butterflies in your field guide, or looking at photos or drawings to compare them to your butterfly.
Finding butterflies in the field
But of course, all the skills in the world won't help you if the butterflies are nowhere to be found, right? Or, for that matter, if you can't get close enough to see them well. So here are a few tips to help you get better looks at butterflies than you might otherwise.
Sun-- Don't let your shadow pass over the butterfly you're watching. A sudden shadow tells the butterfly a predator may be looming above and about to strike. It's a great way to startle a previously resting butterfly into flight.
Speed-- Move slowly and steadily when approaching a butterfly for a photo. You can walk at any speed you like most of the time, but when you're trying to sneak closer to a resting butterfly, sudden movements might startle it into flight. (In fact, I often first spot a butterfly when it startles and takes into the air from wherever it was resting beside the path. Then I have to watch and/or chase it in hopes it will land again somewhere.)
Stillness (part 1)-- Butterflies are much easier to identify and photograph when they're not in flight. Although they do seem to spend most of the time in the air, you're not likely to get a sharp photo of a flying butterfly. Although (with practice)you can identify butterflies in flight as you pick out certain field marks that help you rule out possible IDS, your camera is unlikely to be able to capture those field marks in focus enough for an iNaturalist confirmation. So a better plan is to follow the butterfly, ready to look more closely and/or photograph it as soon as it sets down on a flower or leaf.
Stillness (part 2)-- If you get frustrated at chasing airborne butterflies, you could also try lying in wait for them. Select a flowering plant and wait discreetly nearby. Any butterflies that stop for a sweet meal will be easy to view and photograph. There's no guarantee that your specific plant will host butterflies while you watch, but it's still worth a try if chasing butterflies isn't working for you.
Happy butterflying! Let me know what you see, or if you have any questions about butterflies, in the comments.
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| I found this Monarch nectaring on some New England Asters at Brookside Gardens in Wheaton, MD. |
