Mayslake Plant Notes

by Carl Strang

This is the time of year when the prairies and meadows at Mayslake Forest Preserve are spectacular with masses of asters, goldenrods and other prairie plants.

Many plants also are fruiting now. I took a moment to study some fallen ginkgo fruits.

They are about an inch in diameter, and each contains a single seed that fills much of its volume.

I have heard they have an awful smell, so this was one of those rare occasions when I was glad for my nose-plugging allergies. I was reminded of the ginkgo seedling I spotted last year below the friary, half a mile distant on the far side of May’s Lake.

Now that I’ve seen the size of that seed, I am less inclined to think that a bird transported it. Now coyote seems the likely disperser, unless there is a female ginkgo off the preserve that is closer.

The red oaks are producing a lot of acorns this fall.

Mayslake doesn’t have many red oaks, but the large ones all seem to have plenty of acorns beneath them.

This may be a regional mast year for them, as I have noticed the same production across the county at Herrick Lake Forest Preserve.

Needless to say, squirrels like mast years.

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Odd Geese

by Carl Strang

Recently I was walking near Batavia’s island park on the Fox River when I saw this goose family.

As you can see, one is banded. What drew my attention, however, was one particularly odd looking individual among them.

As you can see, the bird on the right has a lot of white on it. Is it simply a leucistic Canada goose? I don’t think so. For one thing, the legs are orange. It also has a dumpier body configuration. This bird appears to be a hybrid between a domestic greylag goose (Anser anser) and a Canada goose (Branta canadensis). Intergeneric hybrids are relatively frequent among waterfowl, but don’t ever go anywhere. For more photos and discussion on Canada-greylag goose hybrids, go to this page connected to the Cornell bird lab.

Now take a look at the goose on the left in that last picture. There is an abnormal wing tip protrusion that may be a case of “angel wing,” a condition that develops in very young geese and results in a permanently flightless adult. This is thought to result from malnutrition, and is associated with people feeding inappropriate foods to the mothers or the goslings. Don’t feed free-living ducks and geese; you can only cause harm.

So here are three distinctive birds in the same small group. It’s tempting to think up a narrative that ties these observations together, but unless there is someone who has a longer-term familiarity with these geese, such a connection will have to remain speculative.

Garlic Mustard Follow-up

by Carl Strang

I have a final bit of data to share for this year in my study of garlic mustard removal methods. I returned to this year’s study plots in September to see how much the seedlings had thinned out over the summer. Thinning always occurs, as various mortality factors (including competition among the seedlings themselves) take their toll. I did not expect the dramatic degree of thinning I observed, however.

The bare soil you see in this study plot corner was typical. Median counts were 0 seedlings in the square-meter plots for pulled treatments, clipped treatments and controls. Totals in the 9 square meters for each category were 17 seedlings in clipped squares, 4 in pulled squares, 5 in controls.

That compares to respective totals in May, the last time I counted seedlings, of 700, 609, and 575. I should say that this is a different result than I saw last year. Last year’s May totals were 1002, 747 and 214. Last year’s end-of-season totals were 107, 236, and 3. The two years had much different weather, so I cannot say that this difference is due to the year, to the slightly different plot locations, or to the difference in treatments (treatments applied in March 2009, April 2010). On the other hand, the controls produced similar results in the two years.

The only data I neglected to report last spring, by the way, were the over-winter survival numbers of those end-of-season first year plants. The respective totals were 97 plants in clipped treatment squares, 226 in pulled treatments, and 4 in controls (obviously I missed one the previous fall). Over-winter survival thus was good in all three cases; the main thinning occurs during that first growing season.

Maple Leaf Miners, Understory

by Carl Strang

In addition to the trailing strawberry bush (reviewed yesterday), I looked at leaf miners on understory sugar and black maples at Maple Grove and Meacham Grove forest preserves last week. As was the case with the other study, I was interested in the potential impact of controlled burning on the populations of the tiny moths whose caterpillars mine the leaves. Even after a year, the burned areas still had essentially no leaf litter.

Unburned areas at Maple Grove, and in a separate, off-study-area forest in Meacham Grove Forest Preserve, had plenty of litter remaining.

The upshot, though, is that I cannot identify any impact of that fire on leaf miner populations. This is not because they are all high, but rather because the four genera of miners have been consistently low at Meacham Grove for 15 years, now. This year, likewise, maple leaves were very clean at Meacham.

That result, I suspect, is more from the sustained intensive management at Meacham Grove over the years, with greater removal of understory maple saplings and more frequent and extensive burning. This is consistent with Meacham Grove’s forest having more of an oak component, a sign that it was exposed more to fire in its early days, fire that would have limited maple reproduction and dominance. The differences I have observed between the two forests in understory leaf miner populations thus may reflect a historically significant difference in the ecologies of the two preserves. Certainly the management at Meacham has produced an increase in botanical diversity of forest floor plants there.

In three of the four leaf miner genera, understory populations were higher this year at Maple Grove than at Meacham Grove. At Maple Grove, Caloptilia were present on 8% of understory leaves (2% at Meacham), probable Stigmella were on 3% (0% at Meacham), and Phyllonorycter were on a whopping 19% of understory leaves (0% at Meacham). The difference in Cameraria blotch mines, on 2% of Maple Grove leaves and 0% of Meacham Grove leaves, was not statistically significant (for more on these insects, go here). Though I did not take measurements, Phyllonorycter tent mines to the eye were much more abundant in the unburned, less managed forest block at Meacham Grove, and thus resembled Maple Grove.

At Maple Grove, two of the four insect groups increased over last year. That 19% figure for Phyllonorycter in fact is the highest since before 1996, and it is the fifth time that population has occurred on more than 10% of leaves in that period. The median annual value in those 15 years has been a healthy 6%. Caloptilia likewise have stayed strong, with a median matching this year’s value of 8%. This year’s frequency of 3% likewise is the median value for Maple Grove (probable) Stigmella. Cameraria has stayed low, with a median of 2% (also this year’s Maple Grove value). The respective medians for Meacham Grove have been 1%, 4%, 1%, and 0%. All of this discussion has been about the understory. The forest canopy may produce different results, which I’ll investigate in November.

Trailing Strawberry Bush 2010

by Carl Strang

Last week I began to collect this autumn’s forest herbivore data. Today I’ll focus on the trailing strawberry bush at Meacham Grove Forest Preserve. In last year’s account of this study I expressed concern about a second controlled burn of this forest floor area in 3 years. The 2007 burn had knocked back the plants, and though they had recovered some in 2 years I wondered how they might respond to another burn happening so soon. I am not the only interested party, of course.

These deer I saw while collecting the data are affected by the fall burns, possibly for the better, and the removal of litter may help the plants by removing some insect herbivores. But it was clear that some trailing strawberry bush plants were scorched. As I checked my study colonies of the plants last week I found them looking green and scarcely touched by herbivory. They still are very small, and none produced fruit (2000 was the last year when any of the colonies fruited). Though they were smaller than in 2009, the difference was not statistically significant whether colony size was measured as overall length by width (median value of that product reduced from 5.5 square meter in 2009 to 0.95 in 2010) or by the total ground coverage of the scattered bits composing each patch (median value reduced from 0.28 to 0.1 square meter). Though some of the colonies now are very small, what remains appears healthy, and in general the fire appears to have reduced their competition from other forest floor plants.

Wings Flash

by Carl Strang

I was finishing a bike workout, pedaling the final blocks toward home, when a large insect flew across my path. Green, and with wings and legs widely spread, it gave me the split-second first impression was that I was seeing a praying mantis. But the wings were wrong, proportions were wrong, and it didn’t have the Edward Gorey weirdness of a mantis’ profile in flight. The insect turned around, flew back across the street, and crash landed on a lawn. I stopped, dug out the phone, and used it to photograph what I now realized was a greater anglewing.

The spread of that katydid’s wings in flight reminded me of another recent observation. I have taken opportunities to watch a few Texas bush katydids singing, and have been struck by how much the wings flip out to the sides, especially when compared to the more subtle vibrations of singing meadow katydids. I suspect I may be onto what made the Texas bush katydid I observed at Pratts Wayne Woods have such a slurred short-song, with a quality reminiscent of the broad-winged bush katydid’s corresponding advertisement. Here’s another shot of the Pratts Wayne katydid.

It’s missing a wing tip, and there also was scarring near the base of the left forewing. Such damage may well have caused the dramatically flipping wings to sound abnormal when rubbing together to produce the song. The typical crispness that would come from, say, this undamaged conspecific I saw in the dolomite prairie at Waterfall Glen, is compromised.

By the same token, the broad-winged bush katydid’s wings are shorter and wider, and might be expected to flop around more, so that the slurring typical of that species’ short song results. Experimental manipulations suggest themselves, but I’m not interested in captive studies at present.

Geese Shift Gears

by Carl Strang

The goose family from the parking lot marsh nest returned to Mayslake Forest Preserve’s mansion grounds for a few days in mid-September. Dad is recognizable by the band on his left foot, the two surviving kids can fly now.

For now they are staying to themselves, but the last two weeks have seen goose families across DuPage County coalescing into flocks as they shift toward their winter pattern.

Last Friday this flock on Rice Lake at Danada Forest Preserve numbered close to two hundred birds. The coming couple months will see such flocks build on many lake, river and marsh roosting grounds. From there they will radiate out to lawns and fields to feed during the day. Soon they’ll be joined by northern geese, and the flocks will build to their peak sizes until the freeze concentrates them on the major roosting sites, at which time some will shift south. After that, much depends on the severity of the winter. Winter may not be my favorite season, but the past couple of years I have been enjoying my study of Canada goose winter behavior. As the weather turns frosty I can at least look forward to learning whatever new lessons the geese will have to teach me.

Mayslake Update

by Carl Strang

Today I want to share some miscellaneous notes on what has been happening at Mayslake Forest Preserve. Most of these are reflective of the season. For instance, thousands of migrating dragonflies have been passing through in recent weeks. Most of these have been green darners, with some black saddlebags and wandering gliders. I also saw the preserve’s first swamp darners (but was frustrated in my attempt to photograph them as they patrolled the stream). Some of the green darners paused to mate and lay eggs.

Birds also have been migrating. A good mix of warblers and others, including this scarlet tanager, have been refueling on Mayslake’s insects and berries.

Some insects appear late in the season. An example is this adult locust borer, the preserve’s first record of the species.

Of course, our year-round residents continued their activities, with signs of preparation for winter. For example, I have been seeing more skunk tracks than usual, in one case accompanied by scats.

The season’s progress makes this a time of daily change, and time spent outdoors inevitably brings its rewards.

Return to the Dolomite Prairie

by Carl Strang

I needed to return to the dolomite prairie at Waterfall Glen as part of my targeted singing insects search. This had been my dragonfly monitoring area until I switched to surveying the nearby Des Plaines River by kayak, and I hadn’t been in the dolomite prairie for two seasons.

This is a unique environment, arguably the rarest in the county, as it is a prairie growing in a thin soil layer that has developed atop a shelf of Silurian dolomite bedrock in the few thousands of years since the last continental glacier melted away. In my dragonfly monitoring there I had seen federally endangered Hines emeralds hunting a few times. This prairie is not established as a Hines breeding area, though they are known to reproduce nearby. As I walked through the drier part of the prairie depicted above, I noticed some meadow katydids, including this female straight-lanced.

My particular interest, though, was a small area of tall sedges and grasses in the wetter east end of the prairie.

This is where I took the photograph of the female katydid nymph I shared a couple posts ago, the brown one that might have been a black-sided, might have been a long-tailed. Almost immediately as I entered the area I began to see a few black-sided meadow katydids, including this female.

But that wasn’t all. In addition to one of the highest densities of black-legged meadow katydids I’ve ever encountered, I also began to see all-brown individuals including this female.

This was almost certainly a long-tailed meadow katydid. According to one paper I’d read, as of 1983 at least there were no known places where black-sided and long-tailed meadow katydids occurred together. I don’t know whether that has changed in the quarter-century since that publication appeared, but if not then this could well be the first documentation of such a co-occurrence. Considering the potential significance of this find, I went ahead and collected one of the all-brown males, while taking close looks at others like this one.

It proved indeed to be a long-tailed meadow katydid. As I sampled the area with my sweep net I also turned up some colorful individuals like this one.

It has a brown body, and in fact except for the green legs is much like the all brown long-taileds. I was tempted to regard these as variants of the short-winged meadow katydid, a much more common species, because some of them had very bright yellow abdomen tips.

In the end, though, I had to conclude that this was a population of long-tailed meadow katydids with both brown-legged and green-legged individuals. Photos supported the structure of the green-legs’ cerci being closer to long-taileds’ than to short-wingeds’, and while in the literature I could find some references to long-taileds with green legs I could find no mention of short-wingeds with brown bodies.

Thus this small area at the east end of the dolomite prairie, which also is the only part of the whole site where I have seen Hines emeralds hunting, proves to have considerable scientific value. Unfortunately it may be on the verge of being lost. It is smaller than it was even two summers ago, as reed canary grass is invading and displacing the tall sedges and native grasses. I don’t know if anything can be done about this. Herbiciding the reed canary grass probably would also do in the native species, and as I understand it there are no other options. I have to hope the Hines’ can hunt elsewhere, and that these meadow katydid populations will be able to hang on in the marginal habitat with which they will be left if the trend continues.

Waterfall Glen Woodlands

by Carl Strang

Waterfall Glen is DuPage County’s most biologically diverse forest preserve. It has the greatest topographic variety, the greatest geological variety, the greatest mix of plant communities, covers hundreds of acres and therefore harbors more species than any other preserve. I had a few specific places I wanted to check for singing insects on my most recent visit there, and will need two posts to describe that afternoon sensibly. My first stop was Sawmill Creek.

In particular I hoped to find variegated ground crickets there. I hadn’t noticed any unusual songs along that stream before, for instance during the Roger Raccoon Club’s creek walks, but I hadn’t known then that the variegated ground cricket is a habitat specialist found on pebbly or sandy stream edges. In DuPage County, covered with tens to hundreds of feet of clay-rich glacial till, the one stream most likely to match this habitat description was Sawmill Creek, which has pebbly banks and in places flows right over the exposed Silurian dolomite bedrock. I struck out, though. I heard no trilling species other than Say’s trigs and Carolina ground crickets, even with the SongFinder, and so my tentative conclusion is that this little-studied ground cricket lives elsewhere than DuPage County.

Next I checked out low wet areas in the western part of Waterfall Glen’s forest, some reduced to muddy patches and others still ponded at this point in the season.

Here I was listening for two other ground cricket species, the spotted and sphagnum ground crickets. The latter was the longest shot, as there was no sphagnum moss, but sometimes species have a broader habitat range than the literature suggests. This time, though, I heard no new species in that part of the forest.

As I followed the trail back to my car I got one very good break, however. I heard a meadow katydid’s buzzing song coming from the edge of the woods about 20 feet away. It wasn’t as loud as a black-legged meadow katydid, and anyway the habitat was high and dry. As I approached the singer I realized I recognized the song. Sure enough, it was a long-spurred meadow katydid.

The long pointy teeth on the cerci confirmed the ID.

This finding was a source of great relief. A few posts ago I mentioned that my failure to hear some of these singing at Blackwell Forest Preserve (except when I wore the SongFinder) had me wondering if my hearing was failing rapidly. Such clearly is not the case. So, what was going on at Blackwell? At some point I’ll have to see if I can find out. Incidentally, at both the Blackwell and the Waterfall Glen locations for long-spurreds there were no coniferous plants present, so here is one of those examples of hints in the literature being misleading.

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