How Does One Count Butterflies?

Volume 27 Issue 4, Fall 2022

by Anne Ellis, Butterfly Count Coordinator

On August 6, a typical warm, humid summer day, 60 volunteers set out to count as many butterflies as they could find in a single day. It was our 26th Annual Butterfly Count, and we tallied 3,756 butterflies of 45 species in an area of about 178 square miles in the northwestern corner of Loudoun County.

This takes a lot of effort, and when I ask my friends if they’d like to join a butterfly count, I receive many a puzzled look. Exactly how does one count butterflies, they want to know? The short answer is in whole numbers beginning with one. No need to worry about decimals or fractions. But seriously, it’s really a three-step process.

Step 1: Make sure it is a butterfly and not a moth, plant hopper, grasshopper or other similar fluttery creature. If you surprise a plant hopper or one of the little moths tucked among the grasses along the pathway, you’ll see them for a moment, and then they’ll vanish — not a butterfly habit. The Carolina Grasshopper is large and jumps into the air with patterned wings spread, and for a moment you may think “butterfly.” Of course, a grasshopper looks nothing like a butterfly when it lands. And keep a lookout for the Hummingbird Clearwing and Snowberry Clearwing — two fascinating day-flying moths that don’t behave at all like moths. Fascinating, yes, but not butterflies, therefore we don’t count them.

Step 2: Count how many you see of each kind of butterfly. Do this quickly, as they move around fast. You’ll need help at this point to keep track of your sightings. As a team works its way around a meadow or garden, one person acts as scribe while teammates call out names and numbers, for example: “Four Cabbage Whites, two Tigers (Swallowtails), 20 ETBs (code for Eastern Tailed Blues) — no, make that three Tigers.” And the field checklist is not nicely alphabetized! Butterfly identification guides (like bird guides, tree guides, and others) are organized according to taxonomic order. The first butterflies in the guide are always Swallowtails, followed by Whites and Sulphurs, Gossamer Wings (Hairstreaks, Blues), Nymphalids (Brushfoots), and Skippers. Aren’t butterfly names special?

Step 3: Identify the butterfly. There are about 70 species of butterfly on our August checklist, and many of them are easy enough to identify. Remembering their names just takes practice. But there are several butterflies that look alike or similar, such as the Comma and the Question Mark, or the Pearl Crescent and the Common Checkerspot. Spying out the differences when they are moving around so quickly is challenging. Even our leaders may take extra time to puzzle out a skipper, leaning on two or more guidebooks and experience they may have from other butterfly counts. Accurate identification is certainly important, but sometimes the lack of a clear ID can’t be helped and a butterfly might go on the list as “Swallowtail sp.,” which means “swallowtail of unspecified species.”

When the count day is over, team leaders tabulate their results, which are consolidated into a report submitted to the North American Butterfly Association (NABA). NABA collects reports from all over the country and makes them available to researchers. Check out the results of our butterfly count here.

The 2023 count will be on Saturday, August 5. Please join us and count the butterflies!