2015 Fourth of July Boise Front Butterfly Count

Every July, the Museum sponsors one of eight butterfly counts held for the North American Butterfly Association in Idaho. Volunteers are needed, and no knowledge of butterfly identification is required!

The list of butterflies identified during each year's Boise Front count is submitted to the North American Butterfly Association, which compiles results from butterfly counts throughout North America (including Canada and Mexico) and prints reports every year. Field notes and completed tallies from the Boise Front count are placed on file at the Orma J. Smith Museum of Natural History at The College of Idaho, Caldwell, ID. Most of the butterflies are identified without being captured or are released after they are identified. Any specimens collected during the Boise Front Count are placed in the collection at the Orma J. Smith Museum of Natural History.

The 25th Annual Boise Front Fourth of July butterfly count was held on July 12, 2015. Here's a report from the organizer (Dr. Paul Castrovillo, Curator of Lepidoptera at he Museum).

Attendance was good, with 31 butterfly-hunters turning out – a mixture of veterans with many years’ experience under their belts, several joining us for the first time (one intrepid trooper being less than a year old!), and a fair number falling somewhere between those two extremes.

Weather-wise it was a superb day – the temperature in the morning started off fairly warm, in the mid-70’s, and, as we climbed in elevation throughout the day, wherever we were it continued to hover around the mid-70’s/low 80’s. Clouds came and went, but sunshine predominated most of the day - just the kind of conditions that should have brought out the butterflies in profusion.

Overall we did see a fair number (I don’t think anyone was disappointed) – a total of 44 species, which was not as high as some of our recent counts (57 last year!), but significantly more than the average number seen on many of the other nation-wide 4J butterfly counts, which usually comes in at somewhere around 30 species. Butterflies of note this year included: Monarchs– a species we rarely see on this count, but this was the second year in a row that we’ve seen a few; Hydaspe Fritillary – we only saw five, but that’s the most we’ve ever seen, at least during the past 10 counts; Hedgerow Hairstreak, Woodland Skipper and Small Wood Nymph – three more species that we usually only see one or two of, if any, and this year they were more common than normal, even though we’re still only talking about ten or less individuals.

On the flip-side there were many species that we saw in very low numbers, compared to what is usually expected when the weather is warm and sunny, like it was. This analysis can get kind of tricky because there are some butterflies that are typically found more commonly early in the season (like Sara Orange Tip, Silvery Blue and Spring Azure), some more common during mid-season (Squared-Spotted Blue, California Hairstreak, Common Ringlet and Pale Swallowtail come to mind) and others that are typically seen in greatest numbers later in the summer (such as Phoebus Parnassian, Boisduval’s Blue, Large Marble and Western White). What is common, during a specific year, often bears some relationship to how warm or cold the spring and early summer has been and if the “spring” butterflies are still on the wing usually the “late summer” ones tend to be absent or observed in low numbers. Conversely, if spring has been warm and dry, and the butterfly season is advanced, species like Sheridan’s Hairstreak and Mylitta Crescent are hard to find, while Field Crescents and Variable Checkerspots are abundant. For example, during 2010/2011 we observed 22 and 21 Sheridan’s Hairstreaks respectively. Those same years Variable Checkerspots counted were 94 and 57. The following two years, 2012/2013 Sheridan’s Hairstreaks dropped to 4 and 2 individuals, while Variable Checkerspots soared to 398 and 485. This year we could not find a single Sheridan’s Hairstreak and Variable Checkerspots were at a whopping 6! Silvery Blues, a harbinger of spring were nowhere to be found – while the summer-flying Boisduval’s Blue was only observed four times. Data from this summer seems to be a little difficult to interpret, but it just may be a reminder that things are not as simple as we often try to make them out to be. Even though spring/early summer weather seems to have a strong correlation with what species are common, there are always other subtle forces at work, for example food quality, disease and predator/parasite pressures, and other things that may not always be readily apparent. Hopefully, one day some of the data we are collecting year after year on these counts will shed some light on the impact of some of these other ecological variables.

So thanks again to everyone who came out this year to help, and we hope to see you back again next year for the 26th. If you have any butterfly questions between now and next July feel free to shoot me an e-mail. Also, don’t hesitate to stop in at the Orma J. Smith Museum of Natural History during the first Saturday of each month to look at butterflies or other insects in the museum collection.

Click "download" for detailed results of this and past years' counts: