by Carl Strang


For the most part I find standardized abbreviations of bird species names annoying, but I like the sound of MODO, the code for mourning dove. Early in March the males of that species began advertising with their familiar “bachelor calls.” At Mayslake two of them displayed regularly near the mansion.


On Monday morning I saw a mourning dove entering an opening in the branches of a conifer on the mansion grounds. I remembered that March is not too early for this species to nest, despite the fact that there still was some snow on the ground in shaded places from Sunday’s storm.




I couldn’t really see anything through the hole the male entered, though the photo does reveal some non-coniferous plant material.




Careful not to disturb a potential nester I found a larger viewing hole on the far side of the tree. 




Clearly the bird was looking back at me, but held his ground, and I won’t disturb them again at least for a while. I doubt that incubation has been going on for long. Mourning doves have a clutch of only two eggs, but can nest several times in a season because they start so early. I’m fairly safe in my assignment of gender to the incubating bird. Both members of the pair incubate, but typically the female takes the night shift and the male sits during the day. It was my chance witnessing of his approach that revealed the nest’s location in the first place.

Find the Cottontail

by Carl Strang


Today I want to share a couple photos from my years at the Willowbrook Wildlife Center, the forest preserve facility in Glen Ellyn. Willowbrook has one of the nation’s top wildlife veterinary clinics. One day a particularly talented cottontail escaped its transport cage in the exam clinic. Where did it go?




If you study this photo carefully you will find the rabbit. I want to emphasize that this was entirely the work of the cottontail itself. This is not a posed photo. But it emphasizes the unusual resources wild animals have that we do not see in their every day behavior. By now you no doubt have discovered that the rabbit had managed to jump up to the top of the clinic’s highest cabinet.




The latches on all of Willowbrook’s cages are good, but on rare occasions they are defeated by talented critters. I remember one occasion when a Houdini-esque coyote disappeared from a closed room where it had been left in a latched cage. It turned up in another closed room three doors down the hall. It somehow had undone the latch, jumped onto the top of its cage, climbed up pushing its way through the suspended ceiling tile (which fell back perfectly in place after the animal’s exit, if I remember correctly), then the coyote tightroped the beams until it made the mistake of putting its weight on a tile above the custodial room halfway down the length of the building and fell into the closed room along with pieces of the tile. Remarkably the coyote was not hurt by this escapade, and was kept in high security until it had fully recovered and could be released.

The Ducks Stop Here

by Carl Strang


This spring I have been impressed by the variety of migrant ducks stopping at Mayslake Forest Preserve. They haven’t come in large numbers, and haven’t stayed long, but the diversity has been interesting. So far I have seen (in addition to local mallards) shovelers, wood ducks, pintails, lesser scaup, hooded mergansers, and this bufflehead pair.




In addition, last fall a ring-necked duck spent a day. The brief stays and low numbers suggest that the habitat quality may be limited in some way. On the other hand, two pied-billed grebes have stayed on one of the lakes for several days, now, so there is food at least for carnivorous divers. The migration has just begun, and I look forward to discovering which species give Mayslake a try as their daytime stopover site.

Tree Tracking

by Carl Strang


Tracking is the study of present-moment clues to past events. While my tutorials on tracking so far have focused mainly on animal footprints, there are other forms of tracking. I have in fact provided examples in posts on the mastodon dig  and on glacial geology, as well as various posts on archeology. When I teach tree tracking to kids I always begin by saying that we are not looking for the root prints of trees that got up and walked around. Instead, we are looking for clues in the shapes of trees and their parts, as well as their relationship to their surroundings. Let’s begin with this group of young trees in a forested setting at Waterfall Glen.




Notice how straight they are (though some are leaning slightly; see below), how their main stems are free of major side branches. The first rule of tree tracking is that trees and their parts grow toward the light and away from the shade. Here, thanks to the other young trees shading them from the sides, they each are growing straight up toward their own little bit of unobstructed light above. They have small side branches, but as the lowest of these become too deeply shaded they will die and drop off, which is a second rule of tree tracking. Here are some young trees growing close to much older ones.




Instead of growing straight up, they are angling away from the shade and toward the light provided by the trail cut. They will hold that angle for the rest of their lives, following the third rule, which is that once a tree or its parts have grown they will hold that shape. In fact, one of the delights I find in tree tracking is to take in the entire shape of a tree and imagine how it has grown, dancing in the time-lapse speed-up of my imagination, its parts shaping themselves within the shade and light pattern of each moment along the way. If the old trees died and rotted away, the persisting angle held by the trunks of these younger ones would point to where the old ones had been.




Here is an old tree with its side branches retained (we know it’s old because of yet another rule: parts of trees increase in diameter with age). It is telling us that it grew up in a field or an open woodland where there was no significant shade on any side. The side branches were retained (second rule above), and the entire shape tells us that though this tree now is in a more filled-in woodland, for most of its life this place was more open. So, tree tracking is about more than the trees themselves. They speak to us of the history of the area in which they are growing.

Woodcock Dossier

by Carl Strang


After yesterday’s account of woodcocks at Mayslake, I thought I’d share my dossier  on that species. As always, I began with my observations of the species prior to setting up the dossier in 1987, then added observations coded by date:


Once I got a close look at one beside the Tippecanoe River. It walked slowly, with a peculiar bobbling gait, teetering on its short legs. Courtship display observed near Purdue in IN, in PA, and in DuPage County, IL. Male usually flies to his dancing ground in mid-late dusk, with distinctive mothlike flight (continuous flapping of round wings, with some curves and turns in course). Display begins with male on ground, emitting a flat, buzzing call, “beezt,” at 2-8-second intervals. A close observer hears a faint hiccup preceding (coupled to) this “peent” call. The bird turns occasionally to face in different directions. After several minutes of peenting the woodcock takes off, flying low with a whistling titter sound, then turning and flying upward in a spiraling or zigzagging climb. When the bird is near the apex of his flight he still is roughly over his ground site, and the whistling becomes more frantic and labored, in bursts rather than continuous. Finally he hovers or zigzags at an altitude of at least 300 feet, singing a beautiful plaintive whistling song with repeated phrases of separate notes going up in pitch, then down (usually 3 notes, with increasing emphasis, then 3 notes down with lower emphasis). Finally the bird becomes silent and zigzags steeply back to Earth, usually landing where he started, in a little arena of short grass within an early-shrub-stage old field near heavier brush. Often a bird will have 2-3 alternate ground sites. Began late March, ended by 1MY in northern IL, often extending later (even into June) in Indiana, e.g. at Hartz Lake. One bird was observed dealing with an intruder on 2 different nights at Pratts Wayne Woods Forest Preserve, in 1986. Intruder peented a couple times, resident made a loud long buzzing call, then flew toward the intruder, who took off. The pursuing bird escorted the intruder away the first time, but chased it closely for a long time the second night, eventually returning to his initial site. In NE IL the birds danced for around 45 minutes, going up 3-12 times during that period. As the season grew late, they went up fewer times.

12JL87. Flushed 2 in nearly dry artesian-well pond at Culver Fish Hatchery. Looked a little unsteady in flight: youngsters?

8AP89. No woodcocks flew at Pratts Wayne Woods (I heard 7-9 the previous week, and they flew for a program 4 days before that). Weather cold after a cold front, with snow. Also failed to fly 4 days later. Weather cold through that period. A couple peents each night, no more.

15AP89. Hartz Lake, IN. I approached 2 displaying woodcocks. One walked around a lot, over a 10-15 foot area, stretching up and walking slow or fast, between flights. Other walked only a little. First’s peenting frequency became very rapid once, when another woodcock flew over.

13MY89. Still going strong at Hartz Lake. After quitting in dark, one began peenting intermittently later (I was camping), well after dark, and even flew once, at ~11pm. No moon, dark with intermittent showers.

26-29MY90. Hartz Lake. Display still strong on 26th, with about 5 flights in evening. But number of flights tailed off daily. Both morning and evening displays. Morning pattern the reverse of evening’s. Only peented morning of 30th.

2JE90. Woodcock tracks in muddy rut of path at Pratts Wayne Woods. Interspersed with many beak-probe holes. Holes 1/8″ in diameter, sometimes soft mud produces a little larger hole. Middle toe 1.25-1.5″ long, side toes around 1-1.25″.




28FE00. 3 woodcocks peenting in north part of Warrenville Grove Forest Preserve. At least one did complete display at least once.

27MR00. As I ran the prairie path near the Northwoods subdivision at Timber Ridge Forest Preserve, I heard 2 peents from a marshy area at around 6:15pm, well before the light was dim enough for the usual beginning of the courtship display.

27AP06. Fullersburg. Woodcock probed in wet soil near edge of Salt Creek on Willow Island. Caught a large worm, pulled it out, cheeks bulged as it swallowed. Resumed probing after rocking from foot to foot several times. Later, when approached by a red-winged blackbird, it severely cocked its tail up beyond vertical. When the blackbird moved on the woodcock flew across the creek to a brushy area to the south.

Woodcocks at Mayslake

by Carl Strang


March is the month when woodcock courtship hits its stride. The woodcock is an upland dwelling member of the shorebird group. It has adapted to nesting in brushy or woodland areas adjacent to openings, and feeds on earthworms which it extracts from the ground with its long bill.




I was interested in whether woodcocks were present at Mayslake. The habitat looks right, though the brushy areas are mainly open at ground level, being composed largely of buckthorn and honeysuckle. Some of my anticipation was removed when I flushed a woodcock at the edge of the mansion grounds a couple weeks ago, but that could have been a migrant. I needed to find out if they are displaying on that preserve.


Saturday night I drove to Mayslake. Lights along the parking lot and drive were full on, and it appeared that First Folio was in the mansion preparing for their next play. I noted the hooting of the male great horned owl as I got out of the car, the owl still defending his territory a couple weeks after losing his nest . Chorus frogs sang from the stream corridor marsh. I walked toward the bridge across the little stream, which was in the center of the likely woodcock display area. Almost immediately I heard the buzzing “peent” of a male on the ground. He flew up into the aerial segment of the display as a second male began to call. The flying bird climbed higher, the wing-twitter of his display flight breaking into clusters and sounding more frantic as he reached the top and began his remarkable whistling song. When he broke off and plummeted back down he did not return to his initial dancing spot, but landed instead in the off-leash dog area. I had never been near him, so I wasn’t concerned that I had been a disturbance. He displayed from there a few more times as I searched for more woodcocks, but I found none, and the second male did not display again. With the noisy traffic of 31st Street and Route 83, plus the artificial lights all around and the suboptimal brush, I suspect that this preserve is marginal for woodcocks. As restoration work proceeds the habitat will improve, but that may not change the perception of the birds if the lights and traffic noise indeed pose a problem for them.

Fullersburg Archeology: A Mystery

by Carl Strang


It’s time to conclude my series on Fullersburg Forest Preserve history and archeology. Time to put on the pith helmet one last time and check out a mystery. And if you can cast light on it, I will appreciate the assist.


If you take the informal dirt trail clockwise around the edge of Butler Woods from Rainbow Bridge, it will take you to the Hairpin Turn.




Shortly after you go around that turn you will see a branch of the trail heading right (east) and up the hill. At the top of the hill is a trench, dug no doubt for some agricultural purpose. It’s not a glacial feature.


Just below that trench is a trio of concrete structures whose function at present remains a mystery. These include a 25-foot-long, arc-shaped low wall built of 2’x2’ concrete blocks, one of which is being shifted as a large white oak grows in behind it.




This arc’s concave side faces south, and in the focus of that arc 30 feet further south there is a bunker-like structure 8’ wide, 7’ deep, and 3’ tall, open on the south side with some dolomite flagstones stacked in the bottom, an old decaying piece of lumber on the ground, a few red bricks scattered on top, and an iron ring set in the center of the roof piece on its south edge.




This bunker is dug into the side of the hill. Brookfield Zoo educator Jim Ritt has made the interesting suggestion that the structure was designed for dynamite storage. Its orientation away from farm clearings and buildings to the north that show on the 1939 aerial photo is consistent with this hypothesis. Back, now, to the trail. On the north side of that trail, roughly in line with the center of the arc and the bunker and 10 feet north of the wall, the third structure is a 3’ circular piece of concrete with a rectangular slot through its top that is about the length and depth of one of the wall’s elements.




The axis of that slot is in line with the bunker. These objects are within a string of older trees that are visible in the 1939 photo. Incidentally, piled in a refuse heap a short distance north of there, just south of the swamp and east of the Hairpin Turn, is a rusting tank of the sort used for heating oil in a home furnace, along with two rusted crushed objects which may be identical tanks, and a wheel still bearing its tire.




So that’s where I’ll end this topic, at least for Fullersburg. There are some other archeological features on that preserve I haven’t mentioned, but I’ll leave them, along with the ones I never found, for your own discovery.

Fullersburg Archeology: Old Building Foundations

by Carl Strang


Two old building foundations are waiting your discovery in northern Butler Woods. The informal dirt peripheral trail crosses one of these,




very close to a roadside sign and boulder which indicate that this was where a hunt club paused before crossing 31st Street in the old days. I wonder if this building might have been a rest shelter for hunt participants. If not, it probably was a farm outbuilding.


The second foundation clearly was a home.




It is located near the 31st Street Stem trail, west of Butler Prairie. The stone boundary of a foundation flowerbed still can be seen. An old trail or drive extends south from the west edge of the house. That this area was agricultural is supported by the presence of drainage tiles in the Butler Prairie area. The north edge of the forested block southwest of this house still can be seen as a straight boundary between older trees, and younger ones that have grown up post-agriculture. Many years will pass before the influence of this stage of Fullersburg’s history disappears from the forest.

Garlic Mustard Removal Study

by Carl Strang


One of the challenges facing people trying to restore biodiversity to native woodlands is invasive plants. Earlier  I outlined the general problem in the context of shrubs. The herbaceous plant causing the most trouble in our woodlands is garlic mustard. Garlic mustard is a biennial. Seeds sprout in spring, grow into rosettes of leaves that survive the winter, then the plants grow up, flower and produce seeds in their second spring. At this point in the season the rosettes look like this.




When I was at Willowbrook I undertook to remove garlic mustard from the fenced area that contains the outdoor animal exhibit. When I was transferred to Fullersburg I did the same in the Wildflower Trail area. Both were high quality areas in terms of the native plants that were present, but garlic mustard was expanding, and suppressing the native wildflowers. I started pulling out the garlic mustard each spring, and was gratified by the quick recovery by diverse native species. Then I began trying fall and winter pulling, and got good results with that, too.


My annual review of the scientific literature last December turned up a study* describing success in controlling garlic mustard by clipping the plants rather than uprooting them. I decided to try a study of my own, that would compare results of uprooting plants versus breaking them off, early and late in the season. Yes, a study had been done. But replication is important in science. I wanted to see for myself that new plants can’t grow up from the decapitated roots. Also, the earliest the other researchers had clipped their plants was late April. I wanted to try it earlier. My move to Mayslake was timely, because the restoration program is relatively advanced there, and I can focus on research rather than rescue.


I have set up 3 study plots, each 3 by 3 meters. I used large nails to mark the corners.




When the time came to treat the plots, I temporarily outlined the plot with bright orange string.




Each of the 9 square meters in each plot gets one of 3 treatments: uprooting, breaking off below the lowest leaves in mid-March, and a control that will be left until the plants are about to flower. At that point I will cut them off below the lowest leaves. This last treatment follows a practice recommended by some experienced restoration specialists, who discourage uprooting because it may stimulate germination of garlic mustard seeds in the soil. I used a random number generator (easy to find on the Internet) to determine which squares got each treatment.


Here is an experimental square from which plants were removed.




And here is a control square with the plants still in place.




I counted the plants in each square as I treated them. In the three study plots combined the total number of pulled plants was 1395, pinched off total 1617, and control plants 1176. The overall average density was 155 plants per square meter. Now, I wait and see what will happen. I’ll provide an update later.


(It should be obvious, but I’ll state it anyway, that I could do this kind of manipulation on public land as a forest preserve district employee, but still had to get clearance to do so.)


*Here is the reference for the study I mentioned: Pardini, Eleanor A., Brittany J. Teller, and Tiffany M. Knight. 2008. Consequences of density dependence for management of a stage-structured invasive plant (Alliaria petiolata). Am. Midl. Nat. 160:310-322.


by Carl Strang


A few days ago I provided a guide to this blog. In it I said that WordPress runs comments past me, and I have to approve them before they appear. I was mistaken about that, as I found a comment had been published without my being aware of it. The author, my good friend Hal, was the first person to send a second comment. That makes me think that I am approving senders, rather than individual posts. I think I know what to look for, now, so if you send a question I should be able to find it even if WordPress doesn’t specifically inform me of it. But perhaps it is best to assume that anything you send will appear. If you make a mistake and it comes through garbled, I can remove it, so please don’t be discouraged from commenting.

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