Mixed review for this summer's butterfly count
In July 1993, my wife, Marlene, and I started conducting Fourth of July butterfly counts in north-central Minnesota. That first year we conducted counts at Deep Portage and Itasca State park.
Fast-forward to July 2017 when we completed our 143rd count spanning 25 summers. Cumulative total butterflies counted now exceed 175,000 (176,459 to be exact).
2017 marks the 23rd consecutive year we've held six counts per summer. We are joined by a small, but dedicated band of counters whom we deeply appreciate and give our counts better team coverage.
What have we learned?
Before diving into specifics from our 2017 season, these are a few of the things we've learned over this quarter-century of counts:
• No givens: Just because we see a butterfly species one year does not guarantee we'll see it the next...or even ever again. Case in point is the Poweshiek Skipperling. A few years ago, we may have seen the last one of this small, prairie butterfly in Minnesota. We hope this is not the case. But, as the years go by without seeing a Poweshiek, the odds seem less likely.
• Changing climate: Twenty-five years ago we had "rain date" alternates for each count. Back then, we rarely needed them. Now, we are constantly trying to outguess extremes of heat and cold, wet and dry, gale-force winds, etc. It's becoming rarer that we can go with a count date, and even rain date, scheduled a year in advance.
• Diminishing habitat: Once a year we conduct each of our six summer counts. With the exception of the Nevis count circle in which we live, we generally visit the other five circles only on the count day itself. What we've seen is not a pretty picture. Rather, each year we generally see more chipping away at the habitats that are the homes of the butterflies.
The chipping takes many forms, such as excessing mowing and spraying along public roadsides; ag practices that eliminate pollinator buffer strips along edges of fields; too aggressive — both in terms of frequency and extent — of controlled burns on conservation lands; and private landowners whose overly manicured, golf-course-style lawns have actually produced butterfly deserts.
• Native plants: Our best chances of seeing butterflies are where undisturbed native plants grow. If we've developed a prejudice, those are the spots we try to concentrate our limited time and number of count teams.
Bottom line, even after 25 years, we humbly recognize there is so much more to learn. We feel fortunate to have the best teacher available: Nature herself.
Where does 2017 stand?
I'd give this count season mixed reviews. On a positive note, the year's 9,376 butterflies was up 25 percent from 2016. Last year was down 20 percent from 2015's 9,445. So we are almost back to where we stood in 2015.
The 65 species tallied in 2017 were down only one from the 66 last year. On a more sobering note, three species — European Skipper, Common Wood Nymph and Painted Lady — represented almost half (46.4 percent) of this summer's total butterflies.
Those three species were present on all six counts. They were joined by 10 other species: Mustard White, Clouded Sulphur, Orange Sulphur, Bronze Copper, Meadow Fritillary, Northern Crescent, Northern Pearly Eye, Eyed Brown, Monarch and Peck's Skipper.
While these 13 species represent only 20 percent of the total 65 species, their individuals numbered 6,265. They accounted for two-thirds of all butterflies tallied.
At the other end of the spectrum, five species had no more than two individuals present and counted. They are Checkered White, Bog Copper, Harris' Checkerspot, Green Comma and Dreamy Duskywing. They were this year's true needles in the butterfly haystack.
I mentioned that Deep Portage and Itasca State Park celebrated their 25th year as a count in 2017. How did they fare in their silver anniversary year? Deep Portage doubled its number from last year to 2,097 butterflies. Itasca, on the other hand, dropped for the second year in a row to 1,261 in 2017.
On a more positive note, Bemidji more than doubled last year's total to 2,699. Only five of the 143 counts have produced more than 2,699 individuals.
Though the temperature reached a sizzling 92 degrees, the Bluestem count in Clay County had a healthy increase to 1,302 butterflies, up 457 over 2016.
The remaining two counts had numbers fairly similar to last year. Nevis was up 29 to 1,014 while central Polk County dropped 134 to 1,003.
Nectar sources looked good in 2017; however, dry conditions proved those looks to be deceiving. As a result, flowers didn't have much nectar to offer. So we were not surprised to observe few nectaring butterflies. We did find damper areas were more productive. That is where more butterflies were hanging out.
The 65 species viewed overall in 2017 was slightly below long-term average.
Only five of 25 years had numbers of individuals exceed the 9,376 tallied this year. However, I'm troubled that only three species accounted for almost half of the individuals sighted.
Purpose of counts
A 15-mile diameter circle has been established for each count. During a single day, all living butterflies found in that circle are reported to the North American Butterfly Association (NABA). The citizen-gathered data provides valuable information on butterfly population trends in North American. This year marks the 43rd year that NABA counts have been held.
Northern Crescent update
Northern Crescent is the only species among the 101 we've tabulated over the 25 years to have been present on all 143 summer counts. However, 2017 was the second consecutive decrease in numbers. Only 554 were tallied. That's a dramatic drop of 1,342 from the 1,895 recorded in 2015. Even with diminished number, Northern Crescents were still the fourth most common butterfly on our 2017 counts.
The caterpillars feed on asters. We've become alarmed that excessive mowing and spraying along many roadsides have eliminated many of the asters where they used to flourish. Such actions have reduced other nectar and host plants available as well.
Focus on top five species
Now I'll spotlight five species from our 2017 season:
• European Skipper: Out of the blue, they jumped from 180 on last year's counts to a total of 2,074 this year. European Skipper was the most common butterfly. In 1910, a shipment of Timothy grass hay arriving in London, Ontario contained eggs of this species, called Essex Skipper in Europe. "Euro Skips," as we call them for short, have been expanding their range ever since. Until about a decade ago, we had few on our counts. The abundance of Timothy grass along many roadsides has certainly aided their expansion.
• Common Wood Nymph: For a number of years, this satyr species with fairly large eyespots, had been the second most common species on our counts. Again in 2017, the Common Wood Nymph regained the second spot.
• Painted Lady: After seeing none in 2015 and 2016 during counts and non-counts alike, 1,072 were tallied in 2017. Very curious! They streamed here from locations to our south, dramatically going from no-show status to third most common species this year.
• Regal Fritillary: Happily, we had 144 on our Bluestem count. Happily, because east of the prairies in western Minnesota, this species no longer exists in the eastern U.S. The continental high last year was 146 in Flint Hills, Kan. Our 144 is very impressive, as is the butterfly itself.
• Baltimore Checkerspot: It's the most striking butterfly we have in this neck of the woods. We had a total of 53 on two counts. Previously seen only on our Bemidji counts, we had two on our Itasca count this summer. Those two were the last butterflies seen on that count, a fitting end for the silver anniversary.
Monarchs and more
I'm giving Monarchs mixed reviews for the 2017 season. The 270 adults tallied on our counts this year almost exactly doubled the 136 in 2016; however, those 270 are about half of the 534 recorded on the 2015 counts.
Also, the weekly Monarch monitoring we have been doing for 20 years didn't fare very well in 2017. We found 85 eggs, but only two final fifth instars. In 2016, we found 29 eggs, but still only two fifth instars, so the success rate of final instar Monarchs from those 29 eggs was almost three times better than this year.
In fact, I contend that 2017 produced the most common milkweed that Marlene and I have seen since transplanting from Omaha, Neb. But, at the same time, we saw the least amount of Monarch caterpillar chewing.
It's interesting to note that the 145 adult Monarchs we recorded Aug. 6 last year were the most for any North American count held in 2016. Unfortunately, only 82 adults — 43 percent fewer — showed up on our fall Nevis count earlier this month. What a difference a year can make!
Clearly, the cumulative negative effects of the past two decades that I've mentioned in my previous articles have squarely placed Monarchs in dire straits.
Insect populations can rebound in striking fashion. Will this be the case for Monarchs?
As the curtains begins to descend on the 2017 butterfly season, keep your eyes peeled for these winged wonders. The much-needed, though late-arriving rains of the past few weeks could keep the season going for about six more weeks.
Final food for thought: If you have the opportunity, space, etc., consider planting native plants which serve as a basis of a healthy ecosystem not only for butterflies and other pollinators, but also provide food and shelter to other insects, birds and small animals that complete the circle of life.