Webers tally winged beauties in 17th season of counts
Recently, Marlene and I completed our 17th "4th of July" butterfly count season in north central Minnesota.
We have now completed 95 summer counts in this neck of the woods. This is the 15th straight year that we have held six counts a summer. We are grateful for the handful of enthusiastic counters who join us as we tromp around searching for butterflies.
We tallied 5,583 individual butterflies this year. Though this is a 12.4 percent increase from last year's overall total, results for each count were mixed (percentage change in parentheses): Nevis (up 38.5), Deep Portage (down 40.0), Bluestem Prairie (up 629.3), Central Polk County (also up 250.9), Itasca State Park (up one individual, so no real change) and Bemidji (down 30.2).
Immediate weather patterns coupled with longer-term climate change both impacted our 2009 results. As we have noted in previous years, we find the most butterflies in areas left as natural as possible, unmowed and unsprayed.
These years must be zipping by quickly. For several years, I had not kept up to date on cumulative numbers of butterflies we have tallied on our counts. So it came as a pleasant surprise after this count season to discover we had reached a major milestone: our 100,000th butterfly on our counts!
The biggest surprise was that this feat was achieved by the very last butterfly we encountered on our Nevis count on June 26, a Northern Pearly-Eye.
Only 39 counts were needed to reach our 50,000th butterfly in 2001. Since butterfly activity has been noticeably slower in more recent years, I am not surprised that it took us another 51 counts to reach our second 50,000th butterfly and not until our 90th count held this year.
Northern Crescent update
A small orange and black butterfly, the Northern Crescent, has been found on all 95 summer counts.
This is the only species present on all. Also, it has been the most common species overall with a total of 23,133.
One of every 4.5 butterflies on our counts has been a Northern Crescent. If the current average of 250 per count continues, I project our 25,000th Northern Crescent will occur on the third count in the 2011 season.
Other 2009 tidbits
A Greenish Blue on the Nevis count was the 97th overall different species we have had during our 17 seasons of counts. Still a pleasant surprise after all these years to come across a "new" species for a count.
Eight butterflies present on 2008 counts were no-shows this year. However, we did have ten species appear in 2009 that were not around in 2008. So we had a net gain from 67 to 69 different species present on our counts this season.
Six of the 69 species showed up on all six counts this summer: Northern Crescent, Northern Pearly-Eye, Monarch, Tawny-edged Skipper, Long Dash Skipper and Northern Broken-Dash Skipper.
The 54 different species on the Itasca count this year were the most ever for a single count. However, for 14 of those 54 species only a single individual showed up to be counted. Overall, at least 29 different species were present on each of this summer's counts.
Though it did not seem like it while we were counting, the 177 Monarchs tallied this summer were up 23.8 percent from 2008. Interesting that exactly the same number of 37 were present on each of our first three counts this summer.
Purpose of counts
2009 marks the 35th year that "4th of July" butterfly counts have been held. The North American Butterfly Association (NABA) compiles data from over 400 counts conducted each year in the U.S., Canada and Mexico.
All living butterflies found in an established 15-mile diameter circle on a single day are tallied and reported to NABA. The counts are an example of citizen-gathered data that is useful for scientific analysis.
'Grading' the counts
Now that our 15th year of six counts per season is in the books, I decided to "grade" them.
I devised a rating scale based on where each of those 90 counts fell on the basis of total butterflies tallied. For each season, a maximum of 30 points were possible with a minimum of a least six points.
I had known that our 2001 season had been our "best." This grading scheme confirms that assessment. The 2001 season garnered 29 of 30 possible points.
On the other hand, 2007 with 13 points has been the "poorest." 2008 showed some improvement with a grade of 15 points. Now 2009 is still a little better yet at 17 points.
Using my scale, an "average" season would have netted 18 points. So both 2008 and 2009 are still sub-par. However, the purpose of the counts is to reflect butterfly activity, and I feel our counts have done so regardless of the grading scheme I've devised.
Monarchs and beyond
For the second straight year, the multiple generations of Monarchs advancing north from Texas have had a tough weather obstacle course to navigate. They have had to endure a mixture of drought and floods before arriving at our cooler summer weather around here. All this has held down Monarch numbers.
The Monarchs graph shows some improvement in the number of Monarch eggs and caterpillars that Marlene and I have recorded on our weekly monitoring visits through August 16, compared to the same date last year. However, both years are still just a fraction of Monarch activity present in 2007, one of our best monitoring years since we began our weekly visits in 1998.
For several weeks, fresh, migratory Monarchs have started their journey south to their wintering grounds in Mexico. Rough Blazing Star is a favorite nectar energy source.
Fresh Mourning Cloaks and Milbert's Tortoiseshells have emerged. They will over-winter in tree bark crevices, woodpiles and unheated structures around here. When they re-emerge next spring, they will be the first butterflies we see.