Ode to the prairie

My husband loves prairies; he is an expert prairie biologist. So maybe this is an ode to him.

Last weekend we visited three prairies in northern and west-central Minnesota so Alison could capture the "essence of prairie" in digital form. See her Aug 30 post below for some dramatic examples. I thought I should add that we also saw some animals (besides cows) and some quite unexpected plants while walking around on some of the preserves. For example, do you know what this plant is? Not your typical prairie plant, but useful in many ways -- some illegal.

Sunset on the prairie makes it light up with color. As we were out driving the backroads at sunset we saw this male marsh hawk land in the grass. Alison and I hopped out of the car and tried to sneak up on him to get his picture, but alas he flew quickly away.

Dragonflies were especially abundant, and we managed to get close up to some different species than we see around the Twin Cities. This one was really huge (a whopping 3-4 inches) and extremely lethargic, and let me get right up in his "face".

like this.... I think this is a juvenile (just emerged) Common Green Darner, based on its gray- brown eyes with the yellowish rim, green thorax, brown abdomen, and bi-colored legs. The abdomen has a bright blue lateral stripe in adult males.

Another curious feature is the bulls-eye that appears in front of their eyes. I found a newly emerged Green Darner in my backyard the other day and got a better picture of the bulls-eye. I wonder what its purpose is.

Darners are one of the most common big dragonflies we see buzzing over the fields above our heads. Alison's prairie pictures (below) were full of dragonfly silhouettes. However, they never seem to tire cruising and darting and are hard to find at rest.

Here's another cooperative subject, a Band-winged Meadowhawk, sunbathing on the gravel near sunset. This is also a juvenile, based on its brown abdomen with black stripe. The adults have a red abdomen. The striking amber wing pattern is unmistakable for this species though. Like other meadowhawks, it hunts in low vegetation, bogs, and slow moving water. It is more common in the western US where it has less competition from other small dragonflies.

There were other meadowhawk species flitting through the low prairie vegetation as well. Alison found some individuals that are either Cherry-faced or Ruby Meadowhawks; apparently you can only tell these apart by looking at them under with 20X magnification.





The prairie is not just a flat pancake in northern and central Minnesota. Glaciers left numerous gravel (and boulder) deposits as they pushed south, while scooping out deep gouges that turned into pothole lakes. Drier hilltops and wetter creek bottoms add to the diversity of life that lives there. I had to watch where I was walking through part of the wetter prairie as we scared up frogs and toads. Sometimes they just hunker down and assume you won't step on them. This guy did not want to budge, even when I got my camera lens down 6 inches from his face.

The prairie is an interesting place to explore, and is certainly more diverse than you think when you drive by what looks like monotonous tall grass.

Here there be dragons

In this case, these are good dragons that eat many of those annoying mosquitoes over their several-month lifetime. Damselflies and dragonflies belong to a group of insects (Odonata) that are relatively ancient, and their preserved fossil forms from 300 million years ago look much the same as their descendents do today.

Two sets of wings (which can be operated independently of one another) gives them both speed and maneuverability, and like hummingbirds, dragonflies can fly forwards (at 100 body lengths per sec), backwards (3 body lengths per sec), and hover in place. They can dart out from a perch to catch small flying insects at speeds of 60 mph. Like birds, some dragonflies may hunt from a perch, turning their heads to follow potential prey then darting out to catch them, and returning to the perch to consume them. Other species primarily hunt from the air, cruising back and forth across the wetland to chase down those pesky mosquitos.

The most common species I've seen in suburban wetlands are these:

This is a male 12-spotted Skimmer (aptly named), which is easily recognizable from a distance because the white spots contrast sharply with the dark ones. Only males have the bright blue abdomen (females are duller in color). Skimmers perch horizontally while hunting, which enables amateur photographers to get good pictures of them, even though they are only 2 inches long.

This is a Widow Skimmer which hunts from the tips of weeds in open fields, rather than over the water like its 12-spotted cousin. Males defend small territories, but establish new ones each day, which I'm sure adds to their energetic cost of life.

This is a White-faced Meadowhawk, a small (1 inch) dragonfly common in the low vegetation where it perches to hunt. Being so small, they are vulnerable to predation by insectivorous birds, and therefore don't let you get close enough to get a good photo of them. For better pictures of meadowhawks, see photos of another St. Paul-ite at http://ecobirder.blogspot.com/2008/10/carpenter-dragonflies.html

And lastly, a small (1.5 inch) but very distinctive dragonfly that I only saw once out in a prarie field, the Halloween Pennant, so named because of the black and orange markings on the wings. As you can see in the photo, they hunt from the tips of flower or grass stalks.

Some interesting facts about dragonflies:
They spend most of their life in water growing to adult size; they molt (shed skin) 8-17 times, increasing in size with each molt. In northern climates, they may live 8 years as a nymph, but only one summer season as an adult.

The enlarged and clawed lower lip of dragonfly nymphs can shoot out in 1/100 of a second as far as 1/3 of their body length to snare small crustacean prey. In the absence of fish, they are the dominant predator in ponds.

The gills of aquatic dragonfly nymphs are located inside their rectum; they breathe by moving water rapidly in and out of the anus (note: fresh water turtles do this too).

One mating provides a female with enough sperm for her reproductive lifetime. Although mating events may last hours, the transfer of sperm to the female only takes a second. The rest of the time the male is most likely removing the sperm from any previous mating; his penis is highly modified with a brush that scoops up any sperm and ejects it.

Dragonflies have really beautiful, multifaceted eyes that are particularly
good at picking up motion.

To see some really nice HD photos, go here:

To see a slow-motion video of Dragonfly flight (from David Attenborough's "Life in the Undergrowth"), go here: