Between 1984 and 1987, Neil Dankert and Hal Nagel conducted an intensive inventory of the butterflies of the Niobrara Valley Preserve, making repeated trips each year. Their 1988 publication shared the results of that work, including the 70 butterfly species they observed, along with their preferred habitats. Every year since then (more than 30 years), Neil has trekked back to the Niobrara Valley Preserve in early July as a way to keep tabs on those butterfly populations. During those annual July surveys, he has seen many species repeatedly, but a few have been missing in recent years. That might be because they are no longer at the Preserve, or it might be that their phenology has changed – that they are appearing earlier or later in the year than they used to.
This year, Dr. Cody Arenz from Nebraska Wesleyan University, has started to repeat the intensive survey work Neil and Hal did back in the 1980’s, following the same routes and protocols. Neil is also helping out – showing Cody where they had collected and coming up himself to do some inventory work. I’m hoping the surveys will provide a couple important pieces of information. First, I want to see if all 70 butterfly species found in the 1980’s are still around and using the same habitats. Second, Cody’s work should help answer the question of whether the species Neil no longer sees (or sees less frequently) during his annual July surveys are really gone or just appearing outside his narrow sampling window.
Last week, the Hubbard Fellows and I got to spend a day with both Neil and Cody, looking at butterflies, learning about their natural history, and catching up on the results of this year’s work. I spent some time learning how to identify butterflies back in the 1990’s, but haven’t done much of it for a long while, so it was helpful for me to dive back into it. My expertise, however, is nothing compared to that of Neil and Cody, so I learned a lot by simply listening and observing. The Fellows, too, had a great time soaking in as much butterfly information as they could.
After a meeting, during which Cody and Neil shared their notes with each other and updated this year’s species list, we headed out into the field. There were a few butterfly species Neil really wanted to look for that hadn’t shown up on this year’s list yet. We started by looking for two of those, the Pawnee skipper (Hesperia leonardus pawnee) and Colorado skipper (Hesperia colorado). Neil had a very specific location in mind, where he hoped we’d find dotted gayfeather blooming and good numbers of at least Pawnee skipper, if not the much more rare Colorado.
We climbed the hill Neil directed us to, and I will admit I was skeptical. There were a few dotted gayfeather plants blooming, but they were pretty scrawny and there wasn’t much else in flower. It sure didn’t look like a great place to see butterflies. For the first five or ten minutes, we didn’t see anything flying. Then, something flitted quickly by and someone tried to catch it, but missed. Not long after, another came past and it was captured. Pawnee skipper! It was a first for me, and Neil showed us how to identify it in the field and tell it apart from the other skippers, which pretty much all look alike. (If you’ve never spent time with butterflies, think of skippers as the sparrows, or maybe the sandpipers, of the butterflies. Lots of little brown jobbers with tiny little differences between them.)
Over the next hour, we spotted quite a few Pawnee skippers, but no Colorado skippers. Neil still seemed pleased and said that he always felt the autumn was incomplete until he had found some Pawnee skippers. The Fellows and I were certainly pleased too, mostly with the opportunity to learn from both Cody and Neil. The next morning, the Fellows spent another half day with the experts, looking for more butterflies down along the river. They saw lots of regal fritillaries, which have recently emerged from their summer dormancy and are actively laying eggs now. They also saw many other species, some of which I’ve never seen. I had other work to do, so missed out on that, but I got to hear all about it later.
As you can see from these photos, the prairie at the Niobrara Valley Preserve has already started turning golden brown. Most flowers are done blooming, though a few remain. Among those late flowers are some goldenrods and asters, along with the aforementioned dotted gayfeather (Liatris punctata). However, the biggest gathering of pollinators, including butterflies, moths, bees, and flies, that I saw during the trip was on a big patch of curly cup gumweed (Grindelia squarrosa). Gumweed is an annual native wildflower that many people would dismiss as “weedy”. Regardless, it was apparently making a lot of insects very happy with its pollen and nectar. I bet the Fellows and I spotted at least 20 species of pollinators, including 7 or 8 butterfly species, on a single patch of gumweed.
Butterflies are big fans of lots of other “weedy” plants too, including thistles, ironweed, verbenas, and more. As frequent readers of this blog know, I’m also a fan of those opportunistic plant species that thrive during periods of low competition from nearby perennials. The big patch of gumweed drawing loads of pollinators at the Niobrara Valley Preserve was right in the middle of a two-track road through a pasture. There is a lot of gumweed blooming at our family prairie too – mostly in areas that were heavily grazed a year ago. Those plants will only stick around until bluestems and other grasses recover their vigor and push them out, but while they’re here, they’re much appreciated by butterflies and other nectar/pollen feeders.
Cody will be spending one more year doing butterfly inventory so it’s a little too early dig into comparisons between the 1980’s and now. However, he has already recorded several species Neil hasn’t seen during recent July surveys, so that’s a promising beginning.
The Prairie Ecologist 