Wild Ideas: Fewer butterflies for this year’s count?  

Just when the weather seemed to be improving for butterflies, rain set in the day of Rappahannock County’s annual butterfly count, so what will that mean for the results?

Anecdotal reports of fewer than normal butterflies being sighted have been coming in since spring, matching my own observations. Heavy spring rains were probably a big factor. Butterflies are not built to fly in rainy, cold or windy weather, all of which occurred this year and last year.

Finally, a short stretch of hot, dry weather in July gave hope that butterfly numbers would tick up, and they did a bit where I live. The week before our local count, the number of eastern tiger and spicebush swallowtails were still low on the blooming meadow phlox in one tiny garden that normally attracts up to a dozen. Living on a property that is mostly forest, I usually see lots of these two swallowtails, whose host plants are trees and shrubs. Few meadow butterflies usually show up and, if so, don’t stay for long, despite my landlords and I planting patches of native meadow plants around the property.

Between rain showers, a spicebush swallowtail butterfly grabs nectar from meadow phlox By Pam Owen

Rappahannock’s local count — officially the Little Washington-Rappahannock County Butterfly Count — is one of many counts held throughout the United States this time of year as part of the annual Fourth of July count of the North American Butterfly Association (NABA). I don’t take part in any more but do keep an eye on butterflies and analyze and report in this column the results in this column, which are sent to me by Old Rag Master Naturalists (ORMN), the Virginia Master Naturalist chapter that founded and manages the count.

This year’s Rappahannock count was held last Saturday (July 21). The day before, six swallowtails showed up on the phlox in the same garden, which is about the average this time of year. Some years, as many as a dozen will be nectaring at the same time, especially late in the summer, but other years there are only a few. I was starting to think the weather would not depress count numbers. Last year butterflies were also slow to show up, but count results were good.

What also gave hope for a normal count were the results of another NABA count, at Island Ford, in Elkton, Virginia. Held this year on June 28, this count is smaller in terms of the number of counters and areas counted. Early counts also don’t usually result in as high a number of individual butterflies than counts held later in the summer, like Rappahannock’s, but can be a harbinger when compared to past years’ results for those counts.

In a recent email, Mike Smith, the leader of the Island Ford count, reported that it was “successful.” The number of individual butterflies, 735, showed a vast improvement from the previous year, when only 410 were reported, which had been a “new low,” Smith said.

Unfortunately, late Friday night the rain returned and was forecast to stay for a few days. The next morning, around the time the count was to begin, the rain quit for a while where I live, and the sun broke through the clouds briefly. A few swallowtails came to the phlox, but then the rain returned, the wind picked up and the temperature fell to around 70 degrees — suboptimal conditions for butterflies to be active. The butterflies disappeared again, likely taking cover in the forest nearby.

Another lepidopteran species that normally nectars on the phlox in the garden, the clearwing hummingbird moth, had also been working the phlox since it bloomed. Two had appeared and disappeared with the swallowtails but returned after the rain stopped. The swallowtails, however, didn’t come back until around 5 p.m., well after the count was over.

Clearwing moths, such as this hummingbird clearwing nectaring on meadow phlox, mimic other species and forage at dawn and dusk, and on cloudy days. By Pam Owen

This did not bode well for the numbers that would be reported from the count. ORMN started the count in 2011, and last year’s total, 2,377, was good. The average of all six preceding years for individual butterflies was 2,243. In 2013, a huge anomaly occurred when an extraordinary numbers of eastern tiger swallowtails were counted, 2,375 — the highest number ever recorded for the decades-old NABA count. If that year were disregarded, the average total is 1,817.

On the day after our count, I had coffee with Robin Williams, one of the count’s founders and a team leader. She said that, judging by the areas her team covered, the total number of butterflies is likely to be low, perhaps less than a thousand. Complicating the total, one team, led by a butterfly expert from outside the county did not show because of the weather, so one naturalized site that normally produces good numbers was also not counted this year, she added. This will reduce the overall numbers, so I’ll be looking more closely at areas that were counted, checking that against the average for those sites.

It takes time for the volunteer leaders of our count to check and compile the data, so I usually don’t get the results until fall. Once I have them, I’ll compare them to previous years and to data shared with me by other counts in our area to see how the rainy weather may have affected our count.

Whatever the results, we are likely to see more butterflies later in the summer if we get drier weather. More than one generation of many species of butterflies are produced during the breeding season, so a boomlet may occur in the later generations, as it apparently did here last year.

© 2018 Pam Owen

Pam Owen
About Pam Owen 338 Articles
Writer, editor, photographer, and passionate nature conservationist living in Rappahannock County, in the Blue Ridge Mountains of Virginia. Two favorite quotes: By E.O. Wilson, who coined the term "biodiversity," "Nature holds the key to our aesthetic, intellectual, cognitive and even spiritual satisfaction”; by Douglas Adams, “I love deadlines. I love the whooshing sound they make as they pass by.”