Tutored by the Snow - early winter 2025

November 29

Yesterday some fringed gentians were still blooming. Today, nothing distracts from the stark skeleton of the savanna ecosystem. Shorter-term thinking subsides. Underlying structures come to the fore.

First trees. Then animals. 

This young bur oak is an ongoing triumph. A farmer has cut the trees here, understandably, to make a short-lived cornfield. Then we went to work to restore the millenia-old savanna that still thrived in pockets here and there. Restoration of grasses, wildflowers, and many animal species is relatively speedy. 

But for decades we had no sapling oaks. Instead, what we had were oak bushes. In this photo, there are at least twenty visible. Oak reproduction suffered from two challenges. First, the necessarily frequent fires top-killed them, so after each fire they had to start over. Then, the deer ate the fresh shoots back so often, that for decades none got taller than a foot or two before they'd get burned back again. New plan: This one we protected from both fire and deer. It's on the way to playing the needed role of a savanna tree. 

The two closest oaks have immense limbs that stretch west. Surveys confirm that these trees mark the former line between prairie and oak savanna. To the west (left) was treeless prairie - tall grass and bison - to the horizon. To the east, bur oak savanna with deer and mountain lions.

These two trees probably date back to the early years of Euro-american settlement. The long, low limbs would not have survived the prairie fires coming from the west when this was Potawatomi land. They're an awesome and eery inheritance.  

But in the former cornfields, it's not obvious how to make oak management decisions. All the big trees here (the one still holding their leaves) are Hill's oak. They're the ones that reproduced when the Forest Preserve replaced the farm - in the absence of fire.

Bur oaks are the key tree species here, a fire specialist. How many does the ecosystem want? If we let all the trees here grow, they'd shade out and kill off the understory of rare grasses and wildflowers - along with the rare animal species that depend on them. In the long run, we now believe we want structural diversity. In some areas, the fires are gradually top-killing all the tree species except the bur oaks. We see our challenge this way: let enough of them get sufficiently big to survive the fires most of the time, and then let the fires decide the rest. 

Thus, in areas of few burs, they now look like this: a cage protects from the deer, and a blue-and-white flag indicates that we should rake excess fuel away and backburn around it, until it gets a bit bigger. 

In some areas, with ten or twenty young burs, where there's only space for one big tree, we've stopped protecting them altogether.

But much of the site has none. So here, if you look close, you'll see a scrawny young tree protected from deer with a cage and from fire by a circle of fuel cut and raked away. Once again, if we didn't also back burn, the thirty foot flames of a head-fire would top kill this youngster anyway. 

Animals also deserve some mention.

They're not immediately obvious today. In the photo below a deer, blends with the grass and oak leaves. 

We don't see the white-footed mice, but they leave holes where they seem to come to the surface to take a look or breathe fresh air. Mice and meadow voles are under snow and grass thatch. But they're here by the thousands. 

For most of this walk, I don't see a single bird. I know there are woodpeckers, nuthatches, and chickadees back in the trees, but I'm mostly in the open. I don't see them, but most everywhere I see the scene below:

Scrub sparrows are feeding on the seeds of the tall grasses ... and leaving wing-marks on the snow. 

During the breeding season, when I monitor the birds, I find about forty individuals of about twenty species, spread everywhere. Today in he snow I finally come across the forty birds that live here in the winter. They're all one species and all in one flock. 

The poorly named "American tree sparrow" spends its summers on the arctic tundra and taiga ... and its winters among the grasses. It's a pleasure to watch their "popcorn" feeding behavior, as shown here. 

There were a lot more winter birds here before we cut the buckthorns. The birds that relish their berries are gone now. They were mostly robins but also some bluebirds and cedar waxwings. Our progress on restoring berry-bearing savanna shrubs has been slow. Something else to think about on winter days. But they're also beautiful, so this post will end with a sunset.

For a Somme snow animal tracks post by Rebeccah Hartz, click here. 

For a reminder of how this area looked in July, click here. 

Thanks to All About Birds for the tree sparrow photo.

 

Seed Broadcast - two Videos and their Implications

Below are three views of the Swale Pond in Somme Prairie Grove.  

Every fall, in areas needing restoration, we broadcast seed mixes. We wait for burns and put the seeds in the burned areas if possible. But we mostly get burns in spring, and we want the seeds to overwinter in the soil in most cases. The seeds work their ways into the soil over the winter and thus don't get destroyed by the next spring's grass fires.  

But in the video below, steward Eriko Kojima is broadcasting wet prairie seed in spring. Our wet prairie areas don't burn in most years; they are too wet on the burn days chosen. So we hold back most of that seed mix until spring, when we can take advantage of knowing which areas got a chance to benefit from burns. We generally don't seed unburned areas.  

In this video the chorus frogs and wind provide the sound track. We like to broadcast seed on windy days so the seed gets scattered more widely.

Here we look small, the ecosystem looks big, and yet in our small ways we have learned that we can give biodiversity a big boost, working strategically. 

In the next video, Eriko has spooked the chorus frogs, so they've paused their singing. A zephyr ripples the surface of the pond at the end, reminding us that we're at the mercy of this planet, in so many ways. And there's more to learn. 

In this scene we see the habitats where six different seed mixes went. They were:

Pond - in the water (mostly planted in the fall when the ponds are dry)

Sedge meadow - here on the edge of the water

Wet savanna - the narrow band where Eriko is seeding

Wet-mesic savanna - just up-slope from that - but here comprising most of the right half of this image

Mesic savanna - most of the uplands across the top of this photo

Dry-mesic savanna - the little rise visible just above and to the left of Eriko. 

As we broadcast seed, year after year, we may be making mistakes. We follow practices based on our limited experience and research. The seeds of many spring-blooming plants ripen early, May or June; we broadcast them as soon as we can - as many seem to have strategies that require it. For example, some benefit from the work of ants when the seeds are fresh. But there are many spring species that in our naive early years we held for planting until the following spring, and many of them came up fine, despite a practice frowned on today. For the rest, we believe that fall-planting is better than spring planting, but we have not done the experiments needed to know for sure - species by species. 

It would be good to do such experiments - especially for species that especially need help. If people have done such experiments carefully, they should share the results.    

Half of the 500+ plant species at Somme Prairie Grove were already growing here when we started, in 1980. But most conservative species survived at Somme in very small areas - and very small numbers. So we spread their seeds far and wide, looking for similar habitats or other habitats referenced in the literature - wet or dry - prairie, savanna, or woodland (including the wetland areas of each). 

The other half of the species now at Somme came from seeds we found in other remnant areas nearby. Our unproven methods worked. Most of those original sources are now sadly destroyed to become such developments as parking lots, malls, and the houses that we all live in. 

Somme Prairie Grove is now permanently protected by the Forest Preserve District of Cook County, as an Illinois Nature Preserve, and equally importantly, in the hearts and hands of the Somme volunteer stewards. 

Some of the seeds Eriko is broadcasting will germinate this spring or summer. Some will germinate next year. Once germinated, most will grow slowly. It may take years before they'll be big enough to flower and start making their own seeds. At that point, in many cases, those species will spread to areas where we wouldn't have thought to plant them. Surprises are the rule. But then, some of these species will continue their evolutions as permanent parts of this restored ecosystem under today's conditions. Thus, a month from now, the Swale Pond will look pretty much like it did last year. But an ecological clock will be ticking. There is a grandeur in the slowness of ecosystem recovery.

Somme Falcon Likes New Habitat

On an arctic-cold afternoon, three volunteers were raking sticks and leaves into the remains of four bonfires in Somme Woods. We uncovered the soil to facilitate planting seeds in the under-restoration area. Our work was appreciated by a dark-eyed junco which was busily finding food where we raked. Suddenly a kestrel dove at the junco, which niftily evaded it.

Kestrels aren't so much woodland birds, but western Somme Woods is being restored to its original savanna state, so perhaps we should expect to see more of them. But today was a surprise!

That junco stayed near us for hours as we worked, but the kestrel hung out with us too.

It perched on a nearby snag, still on the hunt. Soon it took off again, swooped down, caught a mouse and flew triumphantly far out over Second Pond marsh. But it was just doing a victory lap, because it then came right back toward us, landed atop the same snag, and let us watch as it tucked into a mousy feast!

"We must be doing something right," said Christos. The kestrel had joined us and hunted in the precise area where we cut brush and opened the canopy to savanna structure on recent workdays. 

We didn't get photos at that time, but you can pretty much see what we saw in the great Somme Prairie Grove shots taken earlier by Lisa Culp Musgrave.

Words by Eriko Kojima

Photos by Lisa Musgrave

Habitat by the Cook County Forest Preserves