Butterfly count numbers align with 10-year average

This year’s Long Point Butterfly Count showed a sharp reduction in the number of Red Admiral butterflies compared to last year. Adverse winter and spring weather conditions in Texas could account for some of the decrease in butterflies migrating north to Ontario.

Lisa Timpf

Advocate Contributor

A group of 25 people combed the landscape within an assigned area to participate in the annual Long Point Butterfly Count on Saturday, July 5.

The Long Point count, sponsored by the Norfolk Field Naturalists, focusses on a 15-mile-diameter circle centered on Long Point Inner Bay.

Count organizer Adam Timpf notes that this year’s count benefited from beautiful weather. Despite that, when they came in from the field, many of the participants felt they hadn’t seen a lot of individual butterflies, or much diversity in species.

With the numbers mostly tallied (one group’s data was still outstanding), the number of species came in at or slightly above the 10-year average, while the number of individual butterflies also hovered around the 10-year average. 

Among the highlights for the day were new count highs for two species, the Hickory Hairstreak and the Silvery Blue.

In addition, a Two-spotted Skipper was spotted during the count for the first time since 2003. Timpf notes there was some suspicion that the butterfly was out there, though it didn’t show itself to counters for a couple of decades.

He adds that it’s possible the presence of phragmites may have affected the numbers of Two-spotted Skippers in previous years. Now that phragmites has been cleaned up a bit, the butterfly populations might have rebounded.

Numbers of the Mulberry Wing Skipper, which was recorded for the first time in the Long Point count in 2020, tied the previous high. On the other hand, swallowtails like Eastern Tiger Swallowtails, Spicebush Swallowtails, and Black Swallowtails showed themselves in lower-than-usual numbers. 

Timpf has been compiling the Long Point Butterfly Count since 2011. Despite almost 15 years in the role, he notes that count numbers are hard to predict in advance. To start with, every species “has different flight times.” Because of the early, warm spring, some butterflies may have been out in their adult form earlier than usual. 

Factor in cold, wet periods, hot spells, and generally unpredictable weather, and it’s hard to guess in advance which butterflies, and how many, will show up on the assigned count day. In addition, the timing of rainfall can also influence when adult butterflies are on the wing.

Some specific species, however, did provide early indicators.

“One thing we did know was that some of the migratory butterflies might have lower counts,” Timpf says. “Winter and spring weather conditions in Texas indicate how many butterflies will make it up to us. We know that populations of some migratory butterflies weren’t going to build like in past years.”

Bearing out this advance information, the count showed a steep decline in the number of Red Admirals compared to last year. This species, says Timpf, can show big variances from year to year. The high for Red Admirals for the Long Point count was 521, but the number dropped to 19 the next year. A year with a low of nine was followed by 410 the following count.

“It’s less to do with things going on up here, and more with the early broods being hindered,” Timpf notes.

While data ebbs and flows, with some species showing boom or bust cycles, it’s the long-term trends that are important. Data from the Long Point Butterfly Count has been collected since 1993, the year the North American Butterfly Association (NABA) kicked off the count for the United States, Canada, and Mexico. Data from around 450 annual counts, each within a 15-mile assigned count circle, flows into the NABA totals.

The Long Point Butterfly Count area, Timpf says, includes a lot of protected areas. “If anything, more habitat is being created,” and participants are able to “survey the same sites as they have for the past ten years.” Not all count areas are so fortunate, with habitat loss being a major issue for many areas.

The NABA web site notes that the dataset from past counts “provided the primary source of butterfly count data for the blockbuster study published in Science: Rapid Butterfly Declines across the United States during the 21st Century.”

The Science study showed that in the United States “butterflies have declined by a staggering 22 per cent in 20 years.” NABA says this serves as “a stark reminder of all the work that must be done to reverse this trend,” urging “immediate action to create a world where butterflies thrive, for the benefit of nature and people.”

The site goes on to add that “NABA’s critical contribution to this groundbreaking study was only possible due to decades of painstaking work by count volunteers,” making the work by those who trudge fields, forests, and roadsides seeking butterflies on count day well worth the effort.

More information about the North American Butterfly Count is available at https://naba.org/.