Prairie Animals | The Prairie Ecologist

Plains sunflower (Helianthus petiolaris). This species is dismissed by many as a roadside or cropfield weed.

Sunflowers are seen by some people as big beautiful flowers, and by others as big ugly weeds. Regardless of aesthetic opinions, however, sunflowers appear to be pulling their weight, and more, in the ecology of the Nebraska sandhills prairies this year. After a long dry year, there’s not much green, let alone blooming, in the sandhills right now. The biggest and most obvious exception is the plains sunflower (Helianthus petiolaris).

Plains sunflower, an annual, is one of the few flowers still blooming in the dry sandhill prairies this summer. Most other plant species have already gone dormant.

While most other plants have given up on this year’s growth because of the very low soil moisture, these annual sunflowers are acting like it’s party time. I imagine the long taproot helps the plant get deep moisture, but its root system isn’t any bigger or deeper than many other sand prairie plants, which sit brown and withered in the surrounding landscape. Of course, being annual plants, plains sunflowers don’t really have the option that perennials do to just shut down for the remainder of the season during stressful years. Once a plains sunflower seed germinates, it’s got exactly one growing season to flower and make seeds before it dies. If it had a motto, it would be something like “Live like there’s no next year!”

A bee fly feeding on a plains sunflower.

I’ll bet this fly is grateful for sunflowers.

There are a lot of insect and other species that should be awfully thankful for the ostentatious blooming of the sunflowers this year. Sunflowers are probably the only thing keeping most pollinators alive at the moment, for example. That’s great for those pollinator species, of course, but also for the predators and parasitoids that live of those insects.

A cuckoo wasp rests on an annual sunflower. These wasps lay their eggs in the nests of solitary bees, and the wasp larvae hatch and devour the young bee larvae and their provisioned food. Thanks to Mike Arduser for the identification.

This grasshopper is probably more glad about the green foliage than the flowers – although it may feed on the flowers as well.

An ant on a sunflower petal. While it makes a good photo, I don’t think the ant was actually interested in what was on the front of the flower.

Ants have their own reasons for appreciating sunflowers – largely independent of the big showy flowers. Sunflowers produce and excrete sweet sticky sap (known as extra-floral nectar) that attracts hungry ants. It’s thought that attracting ants in this way might help repel herbivorous insects that might otherwise feed on the sunflower’s leaves and stems. Ants are not predators to mess with if you’re a hungry caterpillar or other plant-eating insect…

You can read more about prairie ants here.

Ants collecting extrafloral nectar from the backside of a sunflower blossum.

The density of ants on some sunflowers was pretty impressive. I’m not sure if this is out of the ordinary because other food sources are limited, or if I was just noticing more of them because there wasn’t much else to look at…

This assassin bug (a predator) is also taking advantage of the attractiveness of sunflowers to other insects.

Not only are the sunflowers stil blooming – there are more flowers yet to come! What an amazing plant.

While sunflowers are filling an important role this time of year, that importance might actually increase this fall and winter. The seed crop for birds and other wildlife is going to be pretty paltry this year. Sunflower seeds are always a favorite of migrating and wintering animals, but this year, they will be especially critical. So – party like there’s no tomorrow, sunflowers. And, on behalf of the inhabitants of the sandhills prairies… thank you!

Last week, I got to help our Niobrara Valley Preserve staff round up and sort bison from the Preserve’s east bison pasture. Ok, I actually only helped with the sorting part because the bison were already in the corral by the time I got there…

Richard Egelhoff, our bison manager, had decided that, even with good grass regrowth this fall, we were going to have to reduce the herd size in order to get them through the winter. His plan was to sort off the yearling and two-year-old bison and keep the rest. Many of bison to be sold would have been sold anyway, but not until November. Richard hopes that shipping them off early will save enough forage to keep the rest of the herd fed. In total, the east herd was reduced from 475 animals to 355.

The corral system for the east bison herd is essentially a series of gates along a chute. The process starts by moving a group of bison from the larger corral into the chute. Once there, gates are opened and closed to let a few bison at a time down the chute until they are finally winnowed down to a single animal (or a few of the same kind). At that point, Richard opens one of two gates at the end, and the bison either goes left (back to the pasture) or right (into the sale pen).

If you’ve ever been to similar event with a corral full of cattle, it’s a noisy dusty mess. With bison, it’s dusty (especially in a drought) but not noisy. Bison mainly communicate with a series of low grunts. Because of that, there’s no loud bawling of mothers and calves or bellowing of bulls – just the pounding of lots of bison feet on the dirt, accentuated by grunts and the occasional BANG of a gate. It can be a violent process at times, as bison ram into each other or into gates – they ARE wild animals, after all – but we tried to get them through as quickly and calmly as we could. They’re amazingly tough animals.

The bison were pushed down to the corral last Wednesday afternoon and the sorting was finished shortly after lunchtime on Thursday, so the “keepers” spent less than a day in the corral before they were back in their pasture. The bison selected for sale were run through the chutes one more time on Friday morning so the neighborhood vet could check their tag numbers (little clips on their ears) or add a tracking number to any that were missing one. That number is required to be on any animals moved across state lines so that a buyer can track health records for each individual animal.

Now if we can get a few more rains, maybe we can grow enough grass to keep those bison happy and healthy until next spring. By then their 7,200 acre pasture should have plenty of grass again. Come on rain!

Below is a series of photos from last week’s roundup. You can click on an image to see a larger version of it, then click on the arrows to move through the remaining photos. When you’re done, just close the window by clicking on the X in the top left corner. To see more on this subject, click HERE to see a short story from the Omaha World Herald, along with fantastic photos and video by Alyssa Schukar.