Photo of the Week – October 5, 2018

Bison are pretty tough.  At our Niobrara Valley Preserve, and at many other sites in the upper Great Plains, bison make it through the winter without any supplementary feed. They just eat cured grasses, grow a thick coat, and plow through snow and ice as needed.  Bison don’t need humans to help with calving, and they protect their babies very effectively from predators.  It shouldn’t be surprising, then, that animals like that would be completely unfazed by a little rain.

Yesterday, some of our Nebraska staff took a trip up to The Nature Conservancy’s Broken Kettle Grasslands in the northern Loess Hills of Iowa.  Land steward James Baker led us on a very scenic hike before a band of cold rainy weather moved in.  We then piled into some trucks with James and Director of Stewardship Scott Moats and went to visit the resident bison herd.  The bison were peacefully grazing as we drove up, despite the pouring rain.  When we stopped, a small group came over to check us out. Here are a few photos of those rugged bison, who didn’t need to huddle in dry and heated pickups to stay comfortable.

P.S. In case you had any doubt about my nerd qualifications, here’s one more piece of evidence.  As I was working up these photos (in the backseat of a truck heading back to Nebraska) yesterday, I was looking closely at the streaks of rain captured by my camera.  Based on the size of a bison calf’s eye and the length of the rain streaks closest to those eyes, I estimated that my camera captured about an inch of raindrop fall during the 1/250 of a second the camera’s shutter was open.  Now, I’d want to do some actual measuring of bison calves’ eyes to check this, but based on that rough estimation, those raindrops were falling about 250 inches per second.  Now, if I convert that number to miles per hour, I get 14.2 mph.  A quick online search found that raindrops are estimated to fall at about 20 mph.  I was pretty close!!  I mean, given that I don’t really know how big a bison eye is or how close those raindrop streaks were to that eye…  (NERD)

Frosty Monarchs

Adding insult to injury, the overly-ambitious monarchs in Nebraska this spring had to deal with cold wet weather all last weekend.  Temperatures got down to about 30 degrees F, and maybe lower in some places, and much of the prairie was covered in frost at least one morning.  During the days, it was rainy, windy, and cold.

We’d brought several monarch eggs from our garden into the house so we and the kids could watch them develop, and the caterpillars from those eggs seem to be doing very well.  When I went back to the garden, though, I didn’t find either eggs or caterpillars on the remaining plants.  I don’t know what happened, but I wonder if the caterpillars hatched out and then didn’t make it through the weather.  Maybe they’re just hiding really well?

Yesterday, I was out at our Platte River Prairies, and Katharine (Hubbard Fellow) and I spent a couple hours walking around and looking for caterpillars on milkweed with no luck.  In addition, the frost killed the tips of most of the warm-season grasses that were just emerging from the ground, and also wilted a lot of the common milkweed plants.  Interestingly, the whorled milkweed plants I’d seen caterpillars on during previous week seemed to have handled the cold just fine, but we couldn’t find any caterpillars on them.  We did find a few eggs on common milkweed plants, but it’ll be interesting to see how quickly those plants recover from the frost, and whether or not they are able to provide sufficient food for any caterpillars that hatch from those eggs.

This common milkweed plant looked a little wilted from the frost, but looked a lot better than the warm-season grasses surrounding it.
The common milkweed plant on the left was more typical of most of the plants we saw on our walk yesterday. Note the whorled milkweed on the right side of the image (skinny green leaves) – it looks perfectly fine.
This was one of several monarch eggs we found on common milkweed plants yesterday.  We found eggs on whorled milkweed as well.

There was good news from the day, though, which is that I saw two adult monarchs, one of which was nectaring on dandelions.  Maybe we’ll still see more eggs laid by this early migrant population.  Temperatures for the next couple weeks look pretty good, so those eggs might have both bigger milkweeds than their earlier counterparts and better weather as well.

This was one of two adult monarchs I saw yesterday. This one was so intent on feeding it let me army crawl to within a foot or so of it for a photograph.  Its faded color and rough-looking wings make it clear that it’s part of the migratory population that overwintered in Mexico.

While it’s been really interesting to see these monarchs show up early this spring, we’ve also seen some first-hand evidence of why we’re further north than those butterflies usually come to breed.  First, we were worried the butterflies wouldn’t find places to lay their eggs because the milkweed hadn’t emerged when they arrived.  Then we worried that caterpillars hatched out on those tiny milkweed plants might run out of food.  Now we’ve seen a frost and cold rainy weather that appears to have been hard on both caterpillars and milkweed.  Our prairies aren’t exactly giving those ambitious migratory monarchs a warm welcome.  Hopefully, we’ll see at least a few caterpillars turn into adults from this first generation, and their cousins further south will have better luck.  If so, we’ll see our regularly-scheduled influx of monarchs in a few weeks.  By then, we should be ready for them.

P.S.  Let’s just take a moment to appreciate the incredible journey the monarch in the above photo has made…  It hatched out of an egg late last summer, maybe even in Nebraska, and although its parents had been born near where it was born and hadn’t migrated anywhere, this one somehow knew that it needed to fly south.  Not only that, it knew to fly to a particular small spot northwest of Mexico City.  It somehow successfully navigated and survived the trip there, survived the winter with a horde of others like it, and then this spring, traveled about 1500 miles back north to get to the dandelion I photographed it on.  It’s a friggin’ butterfly, folks!  It’s just an amazing world, isn’t it?

Watching Wetland Water Levels – Timelapse Photography

It’s timelapse photography time again…  I downloaded more photos from the cameras at our restored wetland in the Platte River Prairies a couple weeks ago, and have been looking through the images for stories.  One theme that stood out in this batch was the variability of the water level in the wetland through time.

This wetland is directly connected to the water table, but is also supplied by a groundwater-fed stream that brings both rainwater and groundwater from about 25 miles west of us.  Platte River flows and irrigation pumping both influence the water table here in the Platte Valley, as does evapotranspiration by plants – and other factors.  It’s a complicated series of events and processes.  However, in general, we expect the water table to be relatively high in the spring and to decline as summer progresses.  I looked at photos from early June and early July (below) and that pattern of summer decline is apparent this year.

June 8, 2014
June 8, 2014.  A panoramic image created by merging photos from two adjacent timelapse cameras.
July 8, 2014
July 8, 2014.  You can click on each photo to see a larger/sharper version of it.

Seeing the pattern of water level rise and fall through weeks and months is interesting, and timelapse photography allows us to watch that pattern pretty easily.  However, it’s also interesting to look at shorter-duration patterns.  I shared one example of that back in December, with a series of images showing daily water level drops due to evapotranspiration.  Today, I’m sharing a second example of short-term water level changes – this time, it’s due to water coming downstream after a rain event.

In the early morning of June 21, 2014, a big storm system moved through our area, dumping between 2 and 4 inches of rain.  The map below shows the precipitation amounts from that storm.

This photo from http://water.weather.gov/precip/ shows rain amounts for our area on June 21.  The black arrow indicates the location of our wetland.
This image from the National Weather Service (http://water.weather.gov/precip/) shows rain amounts for our area on June 21. The black arrow indicates the location of our wetland.

Rainwater from the storm swelled the stream that flows into our wetland, but also created runoff flow throughout the watershed.  The Youtube video below shows the water level changes in our wetland through the day on June 21, 2014, starting at 7am and ending at 8pm.  The changing light conditions from image to image make it a little difficult to see, so you may have watch it several times to get the full effect.  The foreground, the green peninsula on the left, and the little island just left of center are all good landmarks to help see the water level change.

There’s nothing earth-shattering about stream or wetland water levels rising and falling after a big rain event.  On the other hand, it’s not often we get the opportunity to actually see it happen.  Timelapse photography gives us the opportunity to compress time and see natural processes from a different perspective.  For me, at least, that opportunity helps me better understand and appreciate the variability of the earth we live on.

As always, thanks to Moonshell Media for their help with this timelapse photography project.  If you’re interested in exploring timelapse photography for conservation purposes, you can contact them at 402 817 4313 or info@moonshellmedia.com.