SJF March Summary

by Carl Strang

Weather in March at St. James Farm Forest Preserve was variable, but on the whole was relatively warm with frequent rainy periods. At the beginning of the month there was a little lingering snow on the ground, and ponds were frozen, but all of this quickly was gone.

I used my old GPS unit to map my survey routes and to locate positions of previously discovered cavity trees that might harbor a great horned owl nest. One of these indeed proved to hold the nest, and the female still was present on March 25, late enough to indicate that hatched young were being brooded. Two attempts to find displaying woodcocks were unsuccessful, but during the first evening visit on March 17 I heard what I thought was a short call by a barred owl in the eastern portion of the preserve. Scott Meister reported hearing the species in the forest one evening the following week. No pileated woodpecker observations in March, but recent observations in preserves to the north along the West Branch suggest that the bird or birds seen here earlier may be wandering widely. Canada geese were down to small groups and pairs early in the month. By March 31 a nest was under incubation on the small island in the pond below the former house site.

Canada goose incubating on March 31.

Canada goose incubating on March 31.

Many killdeers were displaying in the restoration project area around the stream early in the month, but these were down to just a few individuals by month’s end. Bird activity generally increased as the season progressed, with the first cowbirds arriving March 8, a pair of hooded mergansers and 2 pairs of wood ducks present in the pond in the NW corner of the preserve for much of the month, sandhill crane flocks frequently passing overhead, a northern flicker and the first golden-crowned kinglets appearing on March 14, tree swallows on March 25, and two pairs of green-winged teals in the restored stream on March 26.

This hooded merganser pair may nest in one of the wood duck boxes at the northwest pond.

This hooded merganser pair may nest in one of the wood duck boxes at the northwest pond.

A shed antler found on March 17 in the forest near Winfield Road matched the buck photographed in the same area on November 1.

Someone found an old deer skull and propped it against a trailside tree.

Someone found an old deer skull and propped it against a trailside tree.

The first snake observed on the preserve was a midland brown snake on March 29. That same day several painted turtles were sunning in the eastern pond.

Western chorus frogs began singing on March 11, and ultimately displayed in three locations. The largest number were in the fringes of the eastern pond, and many also were in two temporary ponds in the meadow north of the entrance drive. Numbers of bullfrogs, large and small, had emerged by March 21.

One of the March 21 bullfrogs.

One of the March 21 bullfrogs.

The first butterfly of the year was a mourning cloak observed on March 21. A cabbage white appeared on March 29. The former overwinters in the adult form, the latter as a pupa. Several small brown moths were active on the forest floor on March 31. One was photographed and appears to be a tortricid, close to several similar species of Pelochrista or perhaps Eucosma.

A possible Pelochrista

A possible Pelochrista

Silver maples were blooming by March 11, and spring beauties by March 31.

Spring beauties were the first native herbaceous wildflowers to bloom at St. James Farm in 2016.

Spring beauties were the first native herbaceous wildflowers to bloom at St. James Farm in 2016.

Restoration clearing of the forest was completed by mid-March, and a new set of stakes presumably marking the new trail route was placed in the final week.


by Carl Strang

By my own subjective criteria, I have to declare that spring finally arrived, with a whimper, on April 16. I wasn’t at Mayslake Forest Preserve that day to see it, but the next day was a cold one, and it was clear that a few trout lilies and spring beauties had bloomed but then closed up in the lowered temperature. The weather stayed cold then, and so it wasn’t until Monday of this week that spring was manifestly present. One of its heralds was a patch of white trout lilies.

A representative bloom.

A representative bloom.

Spring beauties were scattered in little patches across the savanna.

Pink guidelines point the way to the flower’s center.

Pink guidelines point the way to the flower’s center.

A bonus was a colony of bloodroots.

They formed a circle reminiscent of a fairy ring.

They formed a circle reminiscent of a fairy ring.

That warm day also brought the first green darner dragonfly, and mourning cloak and cabbage white butterflies. We haven’t seen the last of the cool weather, but winter appears to be done.


by Carl Strang

Butterflies are the most conspicuous insects, and to the extent that they are representative, they are telling us that insects got through the winter in pretty good shape. Butterflies have been abundant and diverse this spring, both species that wintered here and ones that have migrated north. Earlier I mentioned red admirals in this context, and their congeners the American lady and painted lady butterflies have been showing up as likely migrants as well. A member of a species new to my experience appeared at Mayslake Forest Preserve last Thursday.

Obviously a fritillary, it seemed too big for a meadow fritillary and too small for other species of my acquaintance. Also, it lacked silvery spots beneath the hind wing.

My practice is to photograph doubtful cases when I can, and this time it paid off. The newcomer is a southern species known frequently to wander north, the variegated fritillary.

On Friday I saw 3 question mark and 2 mourning cloak butterflies.

One of the question marks, named for the pale silvery small markings on the underside of the hind wing.

That in itself is not all that unusual, as I have seen both species at Mayslake before. What seemed odd was, in this butterfly-rich spring, these were the first of both species I have encountered on the preserve. Both overwinter as adults, and back in March during the warm weather we experienced, I would expect to have seen them, especially with multiple sightings of both species happening now. What gives? Yet another little mystery to tuck away in memory.

Literature Review: Butterfly Range and Diet

by Carl Strang

This week’s literature review note is about butterflies. Usually we just think of butterflies as delightful, beautiful bits of nature, but those qualities also attract the interest of scientists. The scientists in this case are J. Slove and N. Janz (2011. The Relationship between Diet Breadth and Geographic Range Size in the Butterfly Subfamily Nymphalinae – A Study of Global Scale. PLoS ONE 6(1): e16057. doi:10.1371/journal.pone.0016057). The butterflies they studied are 182 species in the widespread subfamily Nymphalinae. Our local members of this subfamily include such familiar butterflies as the mourning cloak, question mark and red admiral.

Mourning cloaks pass the winter in the adult form, hibernating in a sheltering refuge.

Slove and Janz were interested in seeing if there is a relationship between the diet breadth and the geographic range of these butterflies. They wanted to test a prediction that species which eat more kinds of plants have larger ranges. The diet of interest is not that of the adult butterfly, but rather of the caterpillar.

Mourning cloak caterpillars eat the leaves of trees in several families, so they would be regarded as having a wide diet breadth.

It turns out that the prediction holds. The point is that there are a lot of different kinds of plant-eating insects. Some have broad diets, others have narrow ones. How did this diversity come about? The possibility being considered is that some insects have large geographic ranges, in part because by eating a number of kinds of plants they can spread over the collective ranges of those plants. Over the course of time, circumstances such as climate change (interposing a glacier or desert, for instance), geological events (raising a mountain range or sea, for example) and chance isolations (a few representatives driven to a remote island by a storm, perhaps) divide a wide-ranging species into separate groups that no longer can interbreed. Each group may then specialize on the reduced menu of plants available to them, and over time can evolve into separate species. This is called the oscillation hypothesis, because over a long period of time it predicts an alternation between wide diets and narrow diets within a genetic line.

Spring Comes to Mayslake

by Carl Strang

Yesterday I looked back at late winter on Mayslake Forest Preserve. Today I want to share some early signs of spring. There still was a patch of ice on May’s Lake when the first migrant ducks, some lesser scaup, stopped by.

Flocks of sandhill cranes have been passing over on the nicer days.

We also have seen the first flowers of the season already, on silver maples.

Garlic mustard seedlings have germinated.

Soon I’ll resume my experiments on controlling this problem species. Other recent spring events have been chorus frogs singing, the first active chipmunks, red-bellied woodpeckers calling near where they nested last year, and the appearance of insects that overwintered as adults, including a box elder bug and a mourning cloak butterfly.


by Carl Strang

Last winter over an intermittent series of posts I summarized some of my research on leaf-eating insects in DuPage County forests. Most of that work was in the 1980’s, but I have continued a couple of studies to the present day. One of those is following leaf miners of sugar/black maple leaves . In my study forests I found that the maples host a long list of leaf consumers. Each year the parade of them begins with the tortricids. Here is the adult stage of one of those moths, Choristoneura rosaceana.

Tortricid adult b

The wingspan of this mounted specimen is three-quarters of an inch. Its small larva looks like this:

Tortricid caterpillar b

The caterpillar bites through the major veins of the maple leaf at the base, so that the leaf wilts.

Tortricid collapsed leaf b

This presumably cuts off the leaf’s ability to produce defensive chemicals, and also provides a shelter that protects the caterpillar from birds, which focus on more easily gleaned prey. When the caterpillars become abundant, their numbers get knocked back by parasitic wasps. I found that the wasps’ eggs are readily visible in the parasitized caterpillar.

Tortricid parasitized b

This year I decided to go back to my study areas and see what the tortricids are up to. The bottom line answer is, not much. There were a few, but in my random samples of 20 maple saplings per preserve I found only one tortricid caterpillar, at Maple Grove. There were none at Meacham Grove, though I did see a few on saplings outside the sample. This compares to the peak year of 1982, when 63 percent of maple saplings at Maple Grove and 88 percent at Meacham Grove hosted at least one tortricid caterpillar. I plan to continue taking this measurement in coming years.

Incidentally, while sampling Meacham Grove I checked out the trailing strawberry bush (Euonymus obovatus) plants to see if they have ermine moth caterpillars this year (I reviewed this study last winter). The plants all were clean and green.


At one point I looked down and saw this.

Campaea perlata 1

Sticking out beyond the edges of the enchanter’s nightshade leaf were moth wingtips. I tried holding the camera underneath and taking a photo without looking through the viewfinder.

Campaea perlata 2b

The pair of moths apparently had mated the previous night and were waiting out the day. Having acquired my contingency photo, I carefully inverted the leaf. The male moth took off, but I was able to get a clearer shot of this beautiful pale green, leaf-mimicking Campaea perlata female.

Campaea perlata 3b

On the way out of Meacham Grove I got the opportunity to photograph this mourning cloak caterpillar.

Mourning cloak caterpillar b

All in all, this was an enjoyable return.

Early Insects

by Carl Strang

Large insects are beginning to appear at Mayslake Forest Preserve. For some weeks I have been seeing mourning cloaks, which overwintered as adults.

Mourning Cloak b

The above photo I took at Fullersburg last year. Another butterfly that overwinters as an adult is the eastern comma. This one at Mayslake apparently had a close call, probably with a bird. Note the missing section from the left hind wing.

Eastern comma b

There have been some orange sulfurs, which overwintered in the pupal stage.

Orange sulfur b

Their close relatives the cabbage whites have been common all over the preserve. Earlier  I celebrated the arrival of the first common green darner dragonflies, migrants from the South. The first locally emerging dragonfly I saw was this male common whitetail at Mayslake last week.

Common whitetail immature male b

He is recognizable to species and gender by his wing pattern, but he has newly emerged and so still has the immature coloration on his abdomen. The first mature Mayslake damselflies were eastern forktails.

Eastern forktail male b

The above photo of a mature male is from a few years ago, I believe at Songbird Slough, but this is our most common and widely distributed damselfly.

I have not had good luck photographing bumblebee queens this spring. Bombus impatiens has been common, and I saw one Bombus fervidus near the friary on May 22, at the same honeysuckle bush that hosted two of these:

Carpenter bee 2b

This is the large carpenter bee Xylocopa virginica.

The first monarch butterfly arrived at Mayslake this week.

Monarch 2009 1b

This individual is too clean to have made the trip all the way to Mexico and back. It is an offspring of those that wintered down there, made part of the journey back north, and laid their eggs on milkweed plants they found in the southwestern U.S. I shake my head in amazement at the instincts that guide these insects, with their pinhead brains, through journeys last made by their great grandparents.

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