Disappearing Act

I was driving out to the Platte River Prairies last week when Cody (our Preserve Manager) called. Emma had been doing some mowing and Cody had seen what looked like a toad hopping away from the mower. Being the kind person (and good biologist) he is, he flagged Emma down and grabbed the toad before it got chopped up.

To his surprise, it wasn’t a Woodhouse’s toad, which is what we almost always see. Instead, it was a plains spadefoot, which isn’t actually a true toad (its non-warty skin and other features align it more with frogs than toads). Cody was calling to let me know he was going to hold on to it until I arrived.

A plains spadefoot (Spea bombifrons).

I’ve worked along the Platte River for more than 25 years and this is the first spadefoot I’ve ever seen here (I’ve seen one at the Niobrara Valley Preserve). I guess that’s not surprising since they spend most of their lives underground. If you’re not familiar with the habits of spadefoots (spadefeet?), they’re usually only seen aboveground during or after rainstorms. They emerge from the ground to quickly mate and lay eggs in puddles. Their tadpoles can turn into little froglets within a couple weeks, which sometimes is faster than the puddles disappear.

Once they’re finished with their reproductive activities, spadefoots dig themselves back underground. They have special projections on their rear feet (for which they’re named) that aid in that excavation work. I’d heard they were pretty good diggers, but I’d never seen them in action. Until last week.

When I arrived, Cody handed me the spadefoot and then watched while I put it on the ground and tried photograph it. For the first several minutes, Cody had a front row seat to a sketch comedy show as the little critter repeatedly hopped away from me just as I got it in focus. I was lying on my belly to get the angle I wanted, so I ended up sliding around in the recently-mowed grass after the frog – wary of the little cacti (Opuntia fragilis) that I knew were in the area. I eventually managed a couple reasonable shots, including the one above, but wanted a few more since I figured it might be a while before I got another opportunity.

As the spadefoot hopped away from the camera yet again, I finally grabbed it and set it down on a pocket gopher mound Emma’s mower had flattened. This time, instead of hopping away, the little frog immediately started shuffling its rear feet in the loose soil. As I took advantage of its stationary position to photograph it, it continued moving its legs and Cody and I quickly realized it was starting to sink.

The spadefoot started wriggling its rear legs in the loose sand…
… and started lowering itself into the earth.

As it conducted the subtle excavation with its rear legs, it slowly rotated and began sinking lower and lower into the loose sandy soil. It was hard to understand exactly how it was happening, but it was a smooth and efficient process.

Getting lower…
…and lower…
…until it finally disappeared altogether.

Later, Cody and I compared our memories and agreed it had taken about a minute and a half to disappear. Based on the time stamps from my photos, it was probably more like three minutes, but even so, it was impressively fast. I don’t know how long it would take me to completely bury myself in sandy soil – even with a shovel – but I bet it would be hours, not minutes. After it was gone, I toyed with the idea of digging it back up and trying to get video of it repeating the process but I couldn’t bring myself to do it.

Here’s the only evidence the spadefoot had been there.

As Cody and marveled in the experience, we also wondered what the little spadefoot was doing aboveground. It hadn’t rained for a few days, so it seemed weird for it not to be belowground. Our best hypothesis was that it had been buried in a pocket gopher mound and that Emma’s mower had knocked the top off of the mound and either exposed the toad or made it feel like it needed to change locations. Whatever the reason for its appearance, we were sure grateful for it!

Don’t forget to sign up for one of our two events coming up next month! Our public field day on July 9 will be a great way to see the Platte River Prairies and learn about plants, birds, wetlands, small mammals, insects, and much more. Our two day workshop on Conserving Fragmented Prairies (hosted in conjunction with Prairie Plains Resource Institute) will be a terrific opportunity to explore prairie stewardship strategies with other land managers. Read more about both events here.

Photos of the Week – June 5, 2022

Foxtail barley (Hordeum jubatum) is a great little perennial native grass here in Nebraska, but many people view it as a weed. While it’s a perennial, it acts like an annual in that it often grows in heavily disturbed sites – especially places where other vegetation has been recently flooded out. It’s not a strong competitor, so it only sticks around the same place if that place is repeatedly flooded or otherwise disturbed in a way that prevents other plants from doing well.

Here’s a 2018 photo of foxtail barley in a recently-restored wetland slough in our Platte River Prairies.
I took this photo of a patch of foxtail barley last summer (2021) at sunrise in a different Platte River Prairies site.

One of the characteristic traits of foxtail barley is its long awns, which look like lengthy hairs on its flowering heads. The awns often have a kind of pastel pink or salmon hue to them, especially in the right light. A large patch of foxtail barley can be a gorgeous scene as the colors and textures blend together – especially as they wave and ripple in the breeze.

Foxtail barley, showing off its long awns (the hairlike projections on its flowering heads).

Like any other grass, foxtail barley produces pollen when it flowers. That pollen, in turn, attracts tiny insects to feed on it. Flies seem particularly interested, but they’re far from the only ones. Not surprisingly, congregations of flies and other small insects also attract predators – especially tiny crab spiders, which nestle themselves between the long awns and wait for unsuspecting prey to show up. I noticed both the flies and spiders at one of our wet prairies along the Platte River last week. Then I saw more of them at Prairie Plains Resource Institute’s Gjerloff Prairie yesterday.

The little crab spiders blend well with the awns of foxtail barley.
The spiders’ legs are both similar in color and translucence to the awns.
This tiny spider was feeding on a little bug it had caught at Gjerloff Prairie yesterday.

Photographing the spiders and their prospective prey is very tricky. First, of course, insects are wary of big hulking photographers, so they don’t stick around very well when I approach. Second, though, foxtail barley’s big awns catch even the slightest breeze and seem constantly on the move.

As I tried to photograph the little creatures within those awns last week, I often ended up trying to hold the tips of the awns while shoving my camera (on a tripod) close enough to get the photo I wanted. Most of the time, this ended up in the spider or other creature leaving way before I could compose a shot, but persistence eventually paid off and I managed to find a few more tolerant individuals (including those shown above).

Foxtail barley yesterday morning at Gjerloff Prairie.

I’ve long been a fan of this plucky little grass that can handle conditions most other plants can’t. Its gorgeous ‘head of hair’ is certainly part of the appeal too, of course. Now that I’ve started to pay attention to the interactions going on between its pollen-consuming visitors and the spiders waiting in ambush for those visitors, I love foxtail barley even more.