One of the most striking plants in our prairies this time of year is pitcher sage, also known as blue sage (Salvia azurea). It’s tall, of course, but more importantly, as the surrounding prairie is dominated by green-becoming-gold grasses and big yellow flowers, pitcher sage stands out simply because it is starkly and unabashedly blue.
A few weeks ago, I posted a photo of a bee that specializes on pitcher sage, but there are many more insects commonly seen on the plant. Last week, I spent about 45 minutes in our Platte River Prairies, photographing pitcher sage and as many visitors as I could.
I initially pulled my camera out because there were several monarch butterflies flitting around a patch of pitcher sage. While chasing them around (and, as always, being thankful no one was watching me), I came across quite a few other insects – some of which I managed to photograph.
In addition to being tall, striking, and beautiful, pitcher sage is also pretty good at withstanding drought. During late August of 2012 – a year of extreme drought, pitcher sage stood out against a background of brown dormant grass, blooming just like it does every year. Not only did it provide some welcome color when many other plants were wilting, it gave all the insects pictured above, and many others, something to eat when they needed it most.
I blame whomever named the plant. Giving a plant the name “ironweed”, apparently – according to Google – because of its tough stem, creates an unnecessarily negative connotation right from the start. It’s an unfair connotation for a plant that is both beautiful and important. It’s also a big favorite of butterflies; something I can attest to after spending a couple hours last weekend chasing monarchs and others around ironweed patches at our family prairie.
There are three species of ironweed (genus Vernonia) in Nebraska, and two that are common in the prairies I am most familiar with. Both of those – V. fasciculata and V. baldwinii – seem to act in similar ways, but the first likes a little wetter sites than the second. Both species can occur as scattered plants across a prairie, but are also often found in fairly dense patches where conditions favor them. That patchy local abundance is the first mark against them by people who don’t appreciate their value. The second mark is that cattle absolutely refuse to eat them. This both helps them stand out (especially when blooming) in heavily grazed pastures and helps them spread across those same sites since they gain a strong competitive edge when surrounding plants are all being grazed hard.
Like many other plant species I tend to admire and write about, however, ironweed is not an invasive plant – it’s an opportunist. It takes advantage of soil and management conditions that favor it, but doesn’t just spread aggressively across pastures. If you look online, it’s not hard to find websites that encourage its control in pastures. I dispute that. At least in my experience, ironweed has its favorite locations (often in draws or other low spots where moisture and nitrogen are high) and pulses in abundance within those locations as grazing treatments and weather vary from year to year. At our family prairie, ironweed is fairly abundant in some of the low draws where high nitrogen also strongly favors smooth brome, but while there are years when those patches are thicker than others, the overall patch sizes and stem densities of ironweed aren’t any higher today than they were 15 years ago. That matches what I see elsewhere in central and eastern Nebraska.
(I found a university website online that blamed ironweed for making cattle have to look harder to find grass, thus reducing grazing efficiency. Give me a break. That’s the same attitude that leads to people spraying pastures to remove everything that isn’t grass, and then wondering why they need to fertilize their grass and supplement their cattle’s diet. The same people blame others for the lack of wildlife and pollinators on their land. …Ok, I’m done ranting – let’s talk about butterflies.)
When I arrived at our family prairie last weekend, I immediately noticed monarch butterflies flying all over the place. I’d seen a surprising number of larvae back in July, so figured we might have a good August, but I was still impressed with how many adults I saw. I’m guessing there were 40-50 or more across our 100 acres of prairie. They kept moving, so it was hard to count them…
Almost every monarch I spotted was either flying or feeding on ironweed. A few other flowers got attention too, including wild bergamot (Monarda fistulosa), Flodman’s thistle (Cirsium flodmanii), and some early tall thistle blossoms (Cirsium altissimum), but ironweed clearly monopolized most of their attention. I started stalking monarchs with my camera and eventually found a couple that let me get close enough for to capture reasonable photographs. While I was doing that, I also spotted myriad bees, along with quite a few other butterfly and moth species.
Here are some photos of the butterflies and moths that were kind enough to let me get close. I didn’t ever get a good shot of a bee, though there were at least a dozen species feeding on the ironweed flowers, and I also never caught up to one of the many silver-spotted skipper butterflies that were all over the place.
Ironweed is too beautiful and important for its name. Maybe we need a campaign to rename it, and maybe that campaign would help convince people, including those at a certain unnamed university, to leave this plant alone to do its job. Either way, it might be fun to think about potential names. Any ideas?
One of the best perks of my job is simply that I get to be outside enough to see a lot of interesting ecological phenomena. Today, I thought I’d share a few vignettes from the last couple weeks.
Last year, we set out to count monarch caterpillars on our sites, hoping to compare numbers between various management treatments. We were stymied by the fact that there were almost no caterpillars to be found anywhere, let alone enough to make comparisons. This year, I assumed the numbers would be better, but since finding eggs and caterpillars in May from the early migrants from Mexico that arrived this spring, I haven’t seen any caterpillars until this week. And I only found one this week. Whoopee.
Dodder is a fascinating parasitic plant that wraps its plastic twine-looking self around prairie plants like sunflowers and goldenrods and more. Later in the season, the orange twine dries up and disappears, leaving only the fuzzy spirals of flower/seed heads on the stems of its host plants. If you didn’t see both of them together, you might never guess the twine and fuzzy spirals were from the same plant. This week, dodder is in transition, with both flowers and twine at the same time.
A few years ago, I found out about a fun behavior by male brown-belted bumblebees. As colonies start producing queens for the next year, males spread out across the prairie and wait for those queens to enter the world. The males sit on tall perches for hours, scanning for big females. Once they see one, they (and all the other males who spot her) race to be the first to mate with her. This week, they were at it again. I’m really glad to have been clued into this really cool phenomenon. Otherwise, I’d probably just see the bees and assume they were resting.
Finally, I’d like to thank those who helped with and attended our field day last Saturday. The forecast didn’t look promising but the rain cleared out right before the event started and we ended up having fantastic weather. The attendance was lower than hoped because of the forecast, but we still had people from at least 7 states and U.S. territories and we all learned a lot about prairie ecology and invertebrates. Big thanks to presenters Julie Peterson of University of Nebraska Extension, Rae Powers of Xerces Society, and Sarah Bailey of Prairie Plains Resource Institute, along with Kayla Mollet and Katie Lamke from the University of Nebraska-Lincoln.
Over the last five years or so, I’ve been learning a lot more about pollinators, and that has changed the way I look at prairies. As I walk around our prairies, I often think about how I would see the site if I was a bee trying to find enough nectar and pollen to both survive and provision my eggs. Often, our prairies are full of flowers, but April and May can be pretty tough months. The flowers that are blooming tend to be small and scattered, and I can walk a lot of steps without finding anything.
The lack of available flowers in the spring is not necessarily a new thing. Spring weather is unpredictable, and investing resources in blooming early means risking a late freeze or (in some cases) flooding rains that can scuttle the whole process. However, many prairies today have fewer spring flowers than they used to, and restored prairies (crop fields converted back to prairie vegetation) are often low on spring flowers because finding seed for those species is difficult. Flowering shrubs can help make up for a scarcity of spring wildflowers, but they are also less common these days than they used to be.
Prairie managers and gardeners can both play important roles in helping to provide spring flowers for pollinators. In prairies, allowing shrubs to grow in some areas of the landscape can benefit pollinators in the spring, but also help out increasingly rare shrub-nesting birds during the summer. Thinking about spring flower availability might also help inform prairie management plans, and enhancing restored, or even remnant prairies, to add missing spring wildflowers might be beneficial as well. For gardeners, adding native spring wildflowers can be both aesthetically pleasing and extremely important for the bees and other pollinators in your neighborhood.
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.
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.
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?
Ten days ago, I wrote about monarch butterflies returning from Mexico and flying much further north than is typical, and some of the risks they face because of that. Many of you responded with your own similar observations and stories of monarchs across the country. Since writing that post, I’ve spotted numerous monarchs both at our family prairie and in our Platte River Prairies, and reports to Journey North show monarchs have traveled even further north than we are here.
Earlier this week, my wife got to watch a monarch laying eggs on some small whorled milkweed (Asclepias verticillata) plants in our backyard prairie garden. A monarch (same one?) came by when I was around too, so I snuck out and tried to get photos of it but it was too cagey. At the end of last year, Kim and I were talking about how surprisingly fast the couple of small whorled milkweed plants we’d gotten for the garden had spread. Now we’re worried that we don’t have enough whorled milkweed to support all the eggs that have been laid on them!
Yesterday, I went walking in our Platte River Prairies, hoping to find some eggs there as well. I was looking for common milkweed (Asclepias syriaca) but all I found was more whorled milkweed. Sure enough, I found eggs on some of those plants too, and even spotted a couple tiny caterpillars. All the plants I found were in prairie patches we’d burned and grazed last year. I’m guessing the monarchs had the same impression I did of that grazed habitat – it’s sure easier to find tiny milkweed plants when there aren’t a lot of taller plants and thatch hiding them!
Whorled milkweed doesn’t usually get the accolades or attention it deserves. In our prairies, it is often most abundant in areas where native prairies have been degraded by a long history of overgrazing and broadcast herbicide use (before we acquired the properties). The plants are relatively small (often less than a foot tall) and have small white flower clusters and skinny seed pods. When we’re harvesting seeds for our prairie restoration work, we try to get enough seed to ensure the species will establish in our plantings, but probably haven’t always worked as hard as we should at it.
The monarch eggs and caterpillars I found yesterday were in a restored prairie we’d seeded back in 2000. The patches of whorled milkweed I found were over 15 feet in diameter, and some contained well over 100 plants. I’m awfully glad now that we took the time to find and harvest whorled milkweed seeds during the summer of 1999, and wish we’d harvested even more. Nevertheless, the plants that established back in 2000 have spread successfully and are now helping to rear the next generation of monarch butterflies. When those caterpillars emerge as butterflies, they’ll find themselves in the middle of a large and diverse prairie community, full of flowers for them to feed on. Eighteen years ago, that same location was a cornfield. Today, it is giving some way-too-early monarchs a chance at survival.
Back in July, a small group of us got up early to do some prairie photography. We were attending the Grassland Restoration Network workshop in northwestern Minnesota and wanted to catch the sunrise at The Nature Conservancy’s Bluestem Prairie.
We arrived at the prairie before sunrise, split up, and walked off in different directions, searching for photo opportunities. Not far into my hike, I found a monarch butterfly roosting on a milkweed plant. It was cold and wet and not able to move. The sun wasn’t up yet, but there was nice color in the sky where the sun would appear in just a few minutes. That sky glow provided enough illumination and color for me to take a few good photos of the monarch before I moved on to see what else I could find. Before I walked away, I made note of the location so I could circle back later if I had time.
About twenty minutes later, the sun was up and I was wandering back near where I’d seen the monarch earlier so I stopped to see if it was still there. It was, and the rich golden light from the sun was hitting it squarely. I took some more photos .
These are just two of the images I shot of this butterfly that morning, but they are a good pair to use for comparison. Both are nice photographs. The first is a little flat, but has just enough color and definition of detail to make it work. While not as flashy as the second photo, it accurately depicts the subtle beauty of the pre-sunrise world. The second photo literally sparkles in comparison – every hair, scale, and droplet of water reflects the bright golden sunlight coming from the big orange sun behind me. The details are much more defined, and it is a stronger visual image.
I’d guess that in a poll, most viewers of these two images would say they like the second better, but I bet there are a few of you who prefer the first. (And if I hadn’t shown you the second, most of you would probably think the first is a very nice shot.) I like them both, and am glad I took the time to circle back and get the second set of images.
In photography, light is nearly everything. Composition is subjective, and it’s always interesting to see how different photographers frame the same scene. The ability to recognize and use various lighting conditions, however, is what separates good photographers from the rest. I can’t draw worth a lick, and I stick to very simple and safe color combinations in my clothing because I don’t have any aptitude in those regards. I can see light, though, and am very grateful for that. It makes the world a really interesting place to look at and photograph!
Pollinator populations are in trouble for a lot of reasons. Loss and degradation of habitat, pesticides, and diseases are all major contributors. However, at least in the Central United States, much of the pollinator decline can be tied to spiny pink/purple-flowered plants and the way humans react to them.
On the face of it, thistles seem like they’d be pretty well-liked. Thistle seeds are a major food source for birds and other wildlife, as well as for a variety of invertebrates. The abundant nectar and pollen found in thistle flowers make them one of the most popular plants among both pollinator and non-pollinator invertebrates. As if that wasn’t enough, most thistles have large and/or abundant blossoms, which you’d think would make them very attractive to people. Sure, they’ve got spines, but so do cacti, yucca, and many other plants gardeners love to landscape with. So why do we hate thistles so much?
The cultural dislike of thistles is not at all a new phenomenon; references to the unpopularity of thistles can be found at least as far back as the Book of Genesis in the Bible. There, thistles are mentioned when God curses Adam after he eats the forbidden fruit. Genesis 3:17-18 – “Cursed is the ground because of you… Both thorns and thistles it shall grow for you…” Clearly, if God includes thistles as part of His curse on all humanity, they are not a crowd favorite.
Regardless of why thistles are so widely disliked, our contempt for them causes serious problems for pollinators. This happens in two ways: 1) direct destruction of an important floral resource for pollinators, and 2) major side effects associated with #1.
Because thistles are so important to pollinators, our compulsion to destroy them is a major problem. Sure, some thistle species are invasive and can cause enough ecological damage that their control is warranted. Most thistle species, however, are targeted for destruction purely because they are thistles. Many of those are native wildflower species and are not at all aggressive or problematic. Regardless, there are few places where thistles are tolerated, let alone encouraged. The result is the loss of a big source of food for many pollinators.
While the loss of thistles themselves is a big problem for pollinators, the methods we use to eliminate them can have much bigger impacts. If we were content to dig thistles out of the ground one by one, things wouldn’t be so bad. Of course, that’s not always feasible – some perennial species such as Canada thistle are rhizomatous and can’t be killed by digging. Herbicide use is the other available option. Spot spraying individual plants or clumps can be relatively innocuous, but only if the person spraying is judicious and selective about what they spray.
However, working thistles one by one takes a lot of time, and just because we hate thistles doesn’t mean we want to spend a lot of time getting rid of them. Broadcast herbicide spraying, by airplane or boom sprayer, can kill lots of thistles in very short order. It’s a great way to get rid of all those unsightly pink flowers in one fell swoop…at least for that season. Unfortunately, broadcast spraying also kills a wide array of other wildflowers, and most of those never recover (the ones that do are the ones we tend to like least – like ragweeds).
The grand irony is that because broadcast spraying kills so many non-target plant species, the spaces left open by those dead wildflowers are usually colonized by thistles. Thus, while broadcast spraying is quick, it tends to perpetuate thistle populations by destroying their competitors. (Also, most large thistle populations are there because of chronic overgrazing or some other major disturbance that weakens perennial vegetation and creates space for thistles to grow. Broadcast spraying doesn’t address those underlying issues.) Oh, and by the way, killing off all the wildflowers in a pasture or roadside also wipes out the pollinators that depend upon them for food.
Our cultural dislike of thistles leads us to kill off as many as we can each year. Since thistles are a major food source for pollinators, that’s grave news for pollinator conservation. Our desire for more “efficient” ways to kill thistles has led to even worse news, however – the loss of plant diversity across millions of acres. Since plant diversity sustains pollinators by providing varied and consistent food through the season, losing that diversity at a large scale is devastating. We can rebuild some of what we’ve lost through restoration, and we can save what’s left, but only if we change the way we think about thistles. We’d better hurry; pollinator declines are not slowing down.
I think we need a thistle fan club. Who’s with me?? Let’s do this thing. I’ve come up with a basic logo and tag line (below) to get us started. Click here to get an easily printable version you can hang on your office door or tape to your car window. It’ll be a great conversation starter! In fact, let’s have fun with this. If you feel like it, take a picture of how you displayed the logo and put it on your favorite social media with the hashtag #thistlehelp. Not a social media person? Feel free to email me a photo – maybe I’ll collect some of them and use them in a future post. If you email me, please keep the file size below 1 mb… Use this email address: chelzer(at)tnc.org.
The bees and butterflies of the world are depending on you. This is going to sweep the nation, you’ll see!
During our trip to the Grassland Restoration Network workshop in Minnesota last week, several of us got up early enough to catch sunrise at The Nature Conservancy’s Bluestem Prairie on two beautiful mornings. I shared a few photos from those outings last week, but thought I’d post a few more today. I’ve got lots more…it wasn’t hard to find subject matter to photograph!
If you find yourself traveling to or through northwestern Minnesota (just east of Fargo, ND), I encourage you to make the time to visit Bluestem Prairie Scientific and Natural Area. You can find directions and more information on the site here. The Nature Conservancy owns about 6,000 acres of prairie there, and their ownership is bolstered by several other tracts of conservation land right next door. The prairie hosts nesting prairie chickens and beautiful tracts of northern tallgrass prairie. It’s worth the trip to see it.
Insect migration is a world we’re just starting to discover, and the more we find, the more fascinating that world is. One of the most recent discoveries involves Painted Lady butterflies (Vanessa cardui), a species found on every continent except Australia and Antarctica. Scientists in the United Kingdom knew that millions of painted ladies migrated north from North Africa each year. Until recently, they assumed it was a one-way trip. Now, innovative radar techniques show that the species migrates back to North Africa, taking advantage of high-altitude winds (up to 500 meters off the ground).
In case you’re wondering why painted lady butterflies would bother making the trip, the results from radar readings showed that in one year about 11 million butterflies came from Africa to the United Kingdom, and 26 million went back – so the species apparently benefits from migrating. (The butterflies that return are the offspring of the ones that come). You can a further description of the study here from Science Magazine’s website, and link from there to the full scientific article.
Back in May, I posted about what is being learned about how moths and butterflies migrate in North America. The story is similar, except that (at least at this point!) we think the majority of species migrate northward in the spring, but don’t return south. Sounds like a great project for someone to look into!
I’m particularly fascinated by multi-generational migrations. In North America, we’re familiar with the monarch butterfly migration, which takes place over four generations – each successive generation traveling the next leg of the journey. The fact that each new generation of butterflies knows where to go and how to get there, without having been taught, is about as fantastic a natural phenomena as I can think of.
Monarchs are not the only four generation insect migrant. In fact, there’s a fantastic story about the globe skimmer dragonfly that migrates back and forth from India to Africa over four generations as well – using high-altitude wind currents like the painted lady butterfly. You can read more about that dragonfly migration here.
Continuing advances in technology are allowing us to learn more and more about the lives of insects and other small creatures. We’re starting by looking at the migrations of large showy insects such as butterflies, moths, and dragonflies, but I wonder how many smaller, less charismatic species are making long-distance trips that we’ve just never noticed. I’m looking forward to reading many more fascinating stories as the data keeps coming in.