Owls etc. at St. James Farm

by Carl Strang

This has been an eventful spring at St. James Farm Forest Preserve. Thanks to the covid-19 epidemic, volunteers have not been allowed to do restoration work. My response was to take walks through the preserve almost daily in late April and May, gaining a much more detailed understanding of what has been going on there.

Owls, for instance, have provided significant insights. Early in the season I found that great horned owls had commandeered the nest used by Cooper’s hawks the previous two or three years.

My first look at the two nestlings

Though I checked them at a distance, they clearly knew I was there.

Shortly before they branched

The parent, perched nearby, was not concerned.

The youngsters branched (left the nest), and I did not see them beyond a week after that. At the same time, however, I saw an adult great horned owl with a flying youngster at the opposite end of the preserve. Though it is possible that this second nest had been across the road at Blackwell Forest Preserve, the relative number of suitable nest trees leads me to believe there were two great horned owl nests at St. James Farm this year.

The barred owl pair keeps a low profile, and I seldom have heard or seen them. That this is due to the presence of the more powerful great horneds was underlined by my finding on May 13 where an adult barred owl had been killed and plucked. I was left hoping this was a naïve wanderer rather than one of the savvy resident pair, and that hope was intensified when I learned that someone had picked up a young barred owl from one of the interior trails and brought it to the Willowbrook Wildlife Center, the rehab facility for the Forest Preserve District of DuPage County. Some days after that I encountered an adult barred owl with a branched youngster, and Willowbrook deputized me to return their bird to its family.

A leaning black cherry provided a good place for the owlet to climb up.

The youngster quickly climbed more than 10 feet above the ground. His wings were sufficiently developed that he probably could fly.

The owls all were elsewhere by the next morning. Normally I would not share information about owls in this way, but at this point in the season they are so good at staying out of sight that it would be a waste of time for anyone to attempt to find them in St. James Farm’s large forest.

Plenty of noteworthy observations added to my knowledge of the preserve’s flora and fauna. For instance, I found a white river crayfish on the lawn near one of the ponds.

White river crayfish

I got a more detailed list of first flower dates this year, thanks to my frequent visits.

Butterweed pops up in widely scattered open areas of the forest.

This was a cold spring, and first flower dates in May were a median 8 days later than in earlier years of my records. A highlight of the season is the blooming of blackhaw, St. James Farm’s dominant understory shrub.

Though some blackhaws mistakenly were cut last winter by some inexperienced seasonal employees, that was in a limited part of the forest, and even there some were missed, as shown here.

The cut ones will resprout, and the restoration clearing of the forest has been followed by places with bunches of small blackhaws, like this one.

It was an enjoyable season, but now my attention shifts to singing insects. Spring field crickets and green-striped grasshoppers are singing, and periodical cicadas have begun to emerge in some open residential areas.

A Good Burn

by Carl Strang

The Forest Preserve District of DuPage County has invested a welcome amount of effort in restoring the forest at St. James Farm, where I am volunteer steward. Early this spring a large group of trained staff came in and conducted a successful burn of accumulated leaf litter in the main part of the forest. The point of the burn is to kill or at least weaken invasive plants such as garlic mustard and barberry.

The contrast between the unburned trail and the burn area reveals the intensity of the burn.

The burn coverage was about as complete as one could expect.

No burn is complete, however. Some forest floor invertebrate species will need a few years to recover, but there will be plenty surviving in small spots missed by the fire, as well as surrounding areas not included in the burn.

A smaller burn on an earlier date in the area we are clearing of buckthorn was not as complete, because the leaf litter accumulation was relatively shallow and spotty.

I didn’t take any photos of the main burn as it was taking place because I was busy. Our forests historically burned very infrequently, and some of the plants cannot be assumed to be as fire-adapted as the ones characteristic of savannas and woodlands. In particular I was concerned that blackhaws (Viburnum prunifolium), the dominant shrub layer species, might be harmed. So, I worked ahead of the flames, frantically raking dead leaves away from the bases of as many blackhaws as I could reach in the two hours that I had. I did not have time to cover the entire forest, so there were some areas where the flames reached the bases of blackhaw shrubs.

Some blackhaws were heavily scorched.

Other blackhaws were lightly scorched.

Blackhaws I cleared by raking away the leaf litter were unscorched.

In subsequent weeks the forest leafed out, and the blackhaws bloomed.

Blackhaw flower cluster

I spent part of an afternoon assessing scorched vs. unscorched blackhaws. The scorched ones nearly all had plenty of leaves, though a few were killed. Most scorched plants had some flowers, though almost all were limited to 1-5 clusters.

Unscorched blackhaws had abundant flower clusters.

A little less than two-thirds of the scorched shrubs flowered at all, and again, those that did had few. Nine-tenths of the raked blackhaws bloomed, for the most part with many more flower clusters. Sample sizes were large enough to support a strong statistically significant difference. I will continue to watch this, as I am concerned that the scorched plants may have been partly girdled by the flames. I will be recommending that other forest stewards take measures to work with the fire crews and protect the native shrub layer of our woodlands by raking away fuel from shrub bases.

In the meantime, the part of the forest that we have been clearing of buckthorn and other invasive shrubs is showing first fruits of our efforts.

Even in this first year, our treatment area showed an encouraging growth of spring ephemeral herbaceous plants.

One long-term goal will be to promote blackhaw and other native species, so as to restore the shrub layer in the area we have cleared.

I Stand Corrected!

by Carl Strang

In a recent post I identified a shrub at Mayslake Forest Preserve as blackhaw (Viburnum prunifolium). Fortunately I have an excellent botany backstop in Scott Namestnik. In his comment he pointed to the possibility that the plant might instead be the closely related nannyberry (V. lentago), pointing to some characteristics he could see in the photo. I checked my own principal reference, Plants of the Chicago Region by Swink and Wilhelm. They emphasize two characteristics, leaf tip shape and petiole structure, that separate blackhaw from nannyberry.

Blackhaw leaf tips should be “abruptly short-acuminate,” i.e., blunt. Nannyberry leaf tips are long-acuminate, meaning that they are somewhat pinched and drawn out in a longer point, as the above photo from the shrub in question illustrates.

On the petiole, or leaf stem, nannyberry has distinct wings or flanges that are undulate, or wavy, as the photo confirms. Blackhaw petioles, if a little winged, would then be straight and not wavy.

I want to make a couple points, here. First, botanical identifications often require wading through some terminology. If you are not familiar with the terms they can be intimidating at first, but it’s simply a matter of slowing down and looking up definitions. The Swink and Wilhelm book, which I recommend for anyone serious about Chicago region botany, has an excellent glossary with drawings that make meanings clear. The only caveat is that sometimes comparisons are relative. In this example, what is the boundary between “short-acuminate” and “long-acuminate?” Here I used another tool, the Internet search. I found photos of both plants with close-ups of their leaves, and that allowed me to see the distinction.

The second point is that science works best when the scientist is egoless. This time it was easy. I had no ego invested in this identification, and I know that Scott is a topnotch field botanist. I’m a vertebrate ecologist. At the same time, however, I had the plant and all he had was a compressed photo. It was important that I go back and confirm his suspicion, both to make the correction and to learn the difference so my own botanical knowledge would be improved.

I’ll finish by pointing to Scott’s own blog, Through Handlens and Binoculars, which he and his wife Lindsay produce. It’s on the short list of blogs I follow regularly.

Happy New Things

by Carl Strang

However familiar a landscape has become, there always is something new to discover in it. I have begun my second year at Mayslake Forest Preserve, and still I am finding rather large organisms I completely missed last year. Recently I noticed a conspicuously flowering shrub I did not see in 2009.

Unless I miss my guess, this is a blackhaw, one of the native viburnums. Fungi are an entire group with which I have only spotty, passing familiarity. Here is one of the common ones, Polyporus squamosus, which appears on the trunks of several different tree species in spring.

The scaly looking shelves of these reproductive structures are worth taking some time to enjoy. Novelty and surprise certainly are among the factors that draw me again and again into wild places, even ones with which I am reasonably familiar.

%d bloggers like this: