Playing Catch-up 1

by Carl Strang

Photographs have been accumulating in the blog file, but the inspiration to tie them together sensibly hasn’t come, so this week I will simply empty the file out. These all are from Mayslake Forest Preserve, and today’s collection is a miscellaneous one.

We’ve had more rain than usual this far into the summer. Here some fresh mud captured a set of chipmunk tracks.

We’ve had more rain than usual this far into the summer. Here some fresh mud captured a set of chipmunk tracks.

The parking lot marsh surprised me last week with an array of a plant new to the preserve. This is an aquatic buttercup, the yellow water crowfoot.

The parking lot marsh surprised me last week with an array of a plant new to the preserve. This is an aquatic buttercup, the yellow water crowfoot.

This has been a good year at Mayslake for a bumblebee species that varies in numbers considerably between years: Bombus auricomus. The yellow cap on the head, large size, and bold black and yellow pattern are distinctive.

This has been a good year at Mayslake for a bumblebee species that varies in numbers considerably between years: Bombus auricomus. The yellow cap on the head, large size, and bold black and yellow pattern are distinctive.

Queen Anne’s lace is blooming, and on Friday it pointed me to two arthropods new to the Mayslake list. This one has a name I like: Strangalia luteicornis. It is a woods-edge long-horned beetle whose larvae bore into woody plants including grape vines.

Queen Anne’s lace is blooming, and on Friday it pointed me to two arthropods new to the Mayslake list. This one has a name I like: Strangalia luteicornis. It is a woods-edge long-horned beetle whose larvae bore into woody plants including grape vines.

Here a northern crab spider, Mecaphesa asperata, feasts on a flower-visitor fooled by the spider’s camo.

Here a northern crab spider, Mecaphesa asperata, feasts on a flower-visitor fooled by the spider’s camo.

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Great Horned Owl Species Dossier

by Carl Strang

Today’s species dossier is one of my largest. Great horned owls simply attract my attention and interest more than most other animals, and so I have accumulated more notes on them. Great horned owls haven’t been as easy to follow in the years since West Nile virus came into our area. Formerly the crows were reliable blabbermouths as to where the owls were. If our local crows develop resistance to the disease, those days will return.

Owl, Great Horned

Great horned owl

My earliest memory of young great horned owls was in a forest near Purdue, after they had branched one spring [branching is the term for owlets leaving the nest; it is different from fledging, because they reportedly climb down to the ground, walk to another tree, and climb up it]. I know this species primarily from observations in DuPage County, IL, where it is the common large owl, occurring in forests, even small ones. A pair nested annually in the Willowbrook riparian strip for many years, staying as year-round residents. They nested in large willows, 20-30 feet up, first in a nest on branches, then after a storm dislodged the nest, on a provided platform until that tree fell. Incubation begins January or February. The non-incubating male bird usually perches nearby in the daytime, flying away apparently to draw off people or mobbing crows. Owlets (usually 2) branch in May as trees are leafing out, can fly between trees by late May. Young have a distinctive begging call, a rising squeaky-scraping or -grating loud “scaip!” Young disperse usually by the end of October. Before then, they fly all over their parents’ territory, usually staying fairly close together. Branched young mostly sit still, observing all that goes on around them. November brings frequent late afternoon and evening territorial calls: the female’s call is a higher-pitched “WHO-whowhowho-whowhowho-who.” The male’s call has fewer syllables and a lower pitch.  Deep, booming voice. Willowbrook’s territorial birds had a running, never-ending conflict with the caged birds. I also heard calls during childhood campouts on the Tippecanoe River, Indiana, in summer, and later in the woods near the Boiling Springs, Pennsylvania, house in spring.

Pellets and food remains in late winter 1986 at Willowbrook were heavy in rabbit fur and bones in February, meadow voles in March. There were feathers of a gull in May. They covered a territory that included Willowbrook, adjacent residential neighborhoods, and much of the College of DuPage campus, for a total of perhaps 100 acres.

In the Basin of the Chisos Mountains, Big Bend National Park in Texas, they were calling around 5:30am in late July. We saw others there on the road in early evening in the upper desert. They were a bit paler than Midwestern birds.

Some contents of owl pellets at Mayslake, 2009. Prey species are meadow voles, white-footed mice, and a short-tailed shrew.

12FE87. Lots of recently molted breast feathers in Willowbrook Back 40.

8AP87. Photos of branching young owls.

Great horned owl, soon after leaving the nest.

29AP87. Crow remains found under nest area.

5MY87. The pair’s own nestlings now branching, in a willow 50m from nest tree.

6MY87. Remains of a consumed pigeon.

7MY87. The young are in another willow, closer to the nest tree, the one used most by last year’s young when branching. The third (foster, added by Willowbrook staff) youngster is on another branch of the same tree.

8MY87. Another tree change.

1JE87. The young are flying.

5OC87. Adult male beginning to hoot, in afternoon, Willowbrook Back 40.

9JA88. McDowell. Owl flushed from pine grove at south end of north field.

16JA88. McDowell. A great horned owl flew to tree on the west bank of the river, just north of where trees thin to a thread of willows, and where a housing development comes down to the river. There’s a top-blown tree nearby, also several large oaks. Then crows began raising a ruckus nearby in another direction, as though pestering a great horned owl. From that direction a red-tailed hawk soared, but they paid it no heed. It circled an adjacent riparian strip, but when the owl finally broke and flew with a flock of 10 crows in pursuit, the hawk fell in between, and also began to chase the owl. Once it got above the owl and swooped at it, brushing the owl’s back with its feet, but about then the crows caught up and chased both raptors down toward where I had seen the first owl perched, now out of my sight.

30MR88. Willowbrook. Fresh pellet with remains of 2 meadow voles.

25AP88. Both great horned owls off the nest, though in nearby trees.

17MY88. I hadn’t seen great horned owls of Willowbrook Back 40, or heard harassment by crows, in some days. Today I saw 2, upstream of their nest. Crows didn’t harass them for long or in numbers (2-3), apparently too occupied with their own nesting activity.

18JE88. Harassment of owls by crows gradually has increased this month at Willowbrook. Today I observed heavy harassment of a great horned owl by a large number of crows at McDowell Grove F.P. Owls branch at the same time crows are starting to nest, and becoming too busy to harass owls.

22FE89. Owl on a nest at Willowbrook (started incubating within the past 10 days).

26AP89. For the first day since February, there is no adult owl in the nest tree at Willowbrook (have been brooding several days, then a few days of adult perched beside nest with a youngster visible. 2 young. A fox squirrel climbed the nest tree. When it was just below the nest, the adult female flew from a nearby willow, and landed on the nest. The squirrel turned around and began to climb down as she flew in, but was not panicked.

31AU89. Jays vigorously “jay”-ing at an owl well hidden among leaves in a willow top. Chipmunks chucking nearby, below.

30NO89. Great horned owl flying, viewed from behind. Wingbeat of remarkably little amplitude, compensated by its more rapid rate. A fluttering sort of appearance. Wings kept straight. (A behavioral quieting of flight?)

14DE89. Willowbrook nature trail. The owl caught a mouse, according to tracks. Slight blood drops in snow. Many steps trampled snow just beyond the mouse burrow. Then the owl walked, either having swallowed mouse or transferred it to bill. Tracks: landed on mouse tunnel, then walked 5m. Noticeable straddle, up to 1 inch. Track 4 inches long, 3.5 wide, right angle toe pointing to outside distinctive for species. 8 inches center to center for length of step between tracks.

Sketch of great horned owl tracks.

3JA90. The Willowbrook owl pair perching near nest platform.

29JA95. Following a tip, I found a great horned owl on a nest at Maple Grove F.P. Stick nest was built last year by Cooper’s Hawks, according to informant. Nest solidly based in a main crotch 15-20 feet up. Owl had head and ear-tufts up, very noticeable but only from the front. Nest tree right beside a regularly used trail, but not a main trail, less than 200 yards from Maple Ave. and less than 100 yd. from the private school on the east border of the preserve. The owl reportedly has been on the nest less than a week.

18FE99. At Willowbrook, I found this year’s great horned owl nest (they probably have used this site before; not easy to find) in the top of a dead tree trunk, with most of branches gone, a large hollow with little in the way of a roof. Only part of the owl’s head is visible, and only from certain angles. A single fuzzy feather tuft was the give-away. Once while I watched, the bird appeared to stand and turn or shift eggs by moving feet, stepping from one to the other. The owls had been advertising consistently in the area around this tree in the early winter. Crows mobbing nearby earlier in the day (presumably after the non-incubating bird nearby) drew my attention to this area. Only one other candidate tree is nearby.

A sketch I made after finding the nest on February 18.

11MR99. The great horned owl was standing in the Willowbrook nest in the morning.

15MR99. A young bird was seen on the afternoon of the 12th. Today at least 2 young are visible. They were being fed between 3 and 3:30pm.

18MR99. The 2 young owls frequently are standing in the sun in the nest.

12AP99. The Willowbrook great horned young have branched.

A pair of branched young.

16AP99. One of the owl young somehow crossed the rain-swollen Glen Crest Creek to perch between it and the Nature Trail. Flew?

4MY99. At mid-day, a flock of 8 crows pursuing an adult great horned owl over much of Willowbrook Preserve.

27MY99. Both Willowbrook owl young still alive.

11AU99. Only one of the Willowbrook owl young remains.

18AU99. The young owl calling at mid-morning.

8MR00. A neighbor near the north edge of the Willowbrook preserve reported that the pair of great horned owls have been calling in his yard nightly since late January. He gave us permission to look for a nest, and we found it, in the top of a large blue spruce, built on an old crow or squirrel nest. 20 minutes were required to find a small hole through which to confirm the bird’s presence. The tree, perhaps 40 feet tall, is close to a dead‑end side street, in between his house and garage (the 2 buildings less than 20 feet apart), with no other tall trees right there though several others were in the yard. The bird appeared still to be incubating, occasionally turning eggs. We did not see the non‑incubating owl, but numerous potential roosting sites are nearby.

30MR00. We checked the nest again. After a few minutes the brooding bird flew away (sunny, warm afternoon). We could see one young bird clearly; there may have been more. Development seems behind last year at this date by at least a week. Still all white down, as far as we could see.

14AP00. In central Kane County, in a bur oak woodlot of perhaps 10 acres, a great horned owl nest. The nest is an appropriated crow or hawk nest in the top of a large oak. At least one young bird still is inside. The presence of the owls was made clear when the adult male flew past us, pursued by crows. He was small, appearing no larger than the crows. Later I found the nest when walking through the woods. The female flew a short distance, and a few crows called, but she settled in against the trunk of an oak, well camouflaged, and they left her alone.

17JL00. No sounds of great horned owl adults or young at Willowbrook in the evening.

2001: No signs of nest or young around Willowbrook this year, though in the spring an adult seemed to be decoying crows.

Great horned owl tracks. Owl tracks are distinctive in having one of the toes protruding out to the side at an odd angle.

14SE01. An owl called several times in the early dusk at Herrick Lake, south of the former youth campground. I see that this is my earliest record of territorial behavior, by about 3 weeks.

3NO01. Saw an owl, probably a male, at Herrick Lake F.P. in the forest behind a house, north of the big trail loop and south of the former youth group camp. That was in the morning. In the late afternoon, heard one hooting along the Fox River somewhere around Red Oak NC.

27SE02. While walking after a run at Herrick Lake, heard both members of the pair duetting strongly for at least 5 minutes (same area as previous 2 entries).

13FE07. At mid-day in the middle of a winter storm with heavy blowing snow, a great horned owl at Fullersburg holding a recently caught gray squirrel.

3AU08. Great horneds called for a long period, early morning, in my neighborhood. This continued into the dawn hour and overlapped with a cardinal’s singing, past 5 a.m.

21JA09. Mayslake. An elm branch, apparently broken from tree by storm, with bark being consumed by cottontails. Near there, one of the rabbits caught and consumed on the spot last night by a great horned owl (impressions of wing and tail feathers in the snow). Head, feet, a couple bones, and fur all that remain.

29JA09. Mayslake. I found where a great horned owl had walked on the frozen stream surface, heading S out of the woods, taking off before reaching the bridge. The tracks led back to a feeding site, with much cottontail fur and a bone, but no rabbit tracks. Continuing downstream 20 yards I found another area against the bank with fur and blood, and a couple great horned owl footprints again from last night, but again no rabbit tracks. On downstream another 30 yards I found yet a third such site, but again no rabbit tracks. Here there was no feeding, mainly just the impression of the rabbit in the snow. As the owl had walked a few steps before that impression, it must have had the rabbit in its beak. The owl had come from the N or NW. I searched all around but did not find a clear kill site. All of this was under trees with moderately thick brush that makes it seem unlikely the owl would carry prey in there from outside. The shift of location twice would seem to reflect a sense of vulnerability. I wonder if the owl would have removed the head and feet at the actual kill site. The body impression where it first landed on the stream ice was bloody.

Here is one of the stops made by the great horned owl described in the January 29 entry. There is an oval depression where the rabbit’s body was placed.

14FE09. Fullersburg. This year the great horned owls are nesting in last year’s Coopers hawk nest, just west of the Amphitheater. That nest has been available both the past two years, but the owls have chosen to use other hawk nests close to 31st Street in all of the previous 4 years but 1. In that year there were reports of a nest well south of the preserve, but I could not find one on the preserve.

19FE09 Mayslake. I found the great horned owl nest in a hollow willow near the west boundary of the preserve close to May’s Lake. It is not high up, and exposed thanks to the brush clearing, but facing away from the lake may limit its discovery by fishermen.

Great horned owl incubating nest in tree cavity, Mayslake, February 2009.

6MR09. Mayslake. Great horned owl is standing in the nest cavity, apparently brooding.

13MR09. Mayslake. The great horned owl nest tree snapped off at the point of the nest cavity, presumably in the wind storm 3 nights ago (gusts reached 45mph). A dead owlet at the base of the tree, none others nor adult seen, no sign of hurt adult but nest apparently abandoned (cold enough today that an adult would be brooding). There has been enough time that scavengers could have removed other young.

Dead nestling beneath storm-broken nest tree.

10DE10. Neighborhood. I heard a great horned owl calling early this morning.

27JA11. Mayslake. Great horned owl incubating on last year’s red-tailed hawk nest. It was not there yesterday.

Great horned owl incubating nest, Mayslake, January 2011.

10MR11. Mayslake. The owls have abandoned the nest. No sign of disturbance or dead nestling beneath, best guess is the eggs didn’t hatch, either infertile or perhaps the female was forced to abandon during the fierce blizzard at the beginning of February.

18MR11. Mayslake. At a bright mid-day, the great horned owl pair duetted for more than 15 minutes, the male in the west end and the female in the east end of the area 9 hilltop pines.

29MR11. Mayslake. A single hoot from GHO in pines, mid-day, the first I’ve heard since the 20th.  (In September I heard the pair duetting at Mayslake, so they remain at the preserve.)

Chipmunk Puzzler

by Carl Strang

Not far from the coyote den at Mayslake Forest Preserve is a smaller hole. Recently I saw that it had been entered and dug at, but I couldn’t tell by what. Then, after last week’s second snow I saw the following.

The diameter of this burrow entrance is in the 4-6-inch range, typical of skunks’ dens in our area.

The animal which left these tracks was a rodent, larger than a mouse but smaller than a tree squirrel. I followed its trail, which extended from the elevated vicinity of the (now former) friary nearly all the way down to May’s Lake. My immediate thought was chipmunk, and that was an oddity because one seldom sees them out between November and March.

As I followed the tracks it occurred to me that flying squirrels are the same size, and I have seen them at Fullersburg Woods Forest Preserve not too far away to the east. However, this animal never left any sign of side flanges of skin connecting the feet, and it clearly was focused on the ground. Though it went to the bases of trees a few times it never climbed them.

So, while I feel secure in my species ID, I still am left with the question, why did this chipmunk come out at this time of year, and why did it cover so much snow-covered ground? I hope its food cache was not destroyed by the friary demolition. This seems unlikely, but remains an open possiblility.

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.

Red Fox Dossier

by Carl Strang

This is another of my species dossiers, consisting of what I know about a given species from my own experience. I started the dossiers in the mid-1980’s.

Fox, Red

Initial summary: Common resident of mixed fields, brush and woods edges in northern IN, northern IL, south central PA. Also seen on tundra in western Alaska. Near Culver, IN, seen most commonly in winter, when they are frequently active and visible at a distance during the day. In summer, occasionally flushed from resting spot beneath a bush in an old field.

In Alaska they foraged for mice, birds, eggs and young waterfowl in summer. In tall sedges they attempted to pin birds and mice by listening for them, then leaping high and coming down with front legs together and extended straight down. Cached eggs singly, burying them near where found.

Den found on 2AU71 in high bank of tundra lake in bluffs area near Kokechik Bay, western Alaska. Entrance faced south. Well worn paths leading to water 15 feet below and to top of bluff 7 feet above. Entrance about 1 foot in diameter. A second entrance on top of hill. Fish remains.

At Blackwell Forest Preserve, in June, their contact calls heard at night: a high-pitched whining scream or “yipe,” beginning and/or ending with a harsher, rougher, strangled sound. In May 1986, on a walk through the forest at the Morton Arboretum, DuPage County, IL, I felt the need to freeze. Soon a yellowish-colored apparition came toward me, following a dry streambed that passed 30 feet to my left. Soon the red fox came into clear view, a chipmunk dangling from its jaws. It was walking fairly quickly and directly, not looking from side to side. Chipmunks gave single “chip” calls and were silent as it passed. It went by me, then after another 20-30 yards came to a sudden halt, spun around, and at a faster speed came back past me. I suppose it had caught my scent where I crossed the stream.

Trot on thin layer of snow over ice. Width of entire path 5 inches. Travel left to right.

           RF                               LF

RH       o                    LH      o

 o                               o         

     3.5″        10″              3.5″

13JA87. Red fox bed in Willowbrook Back 40. Snow 6″ deep, was compressed in a 15″ diameter area. May have been flattened with feet first. No hair, but claw marks in bottom of bed probably from stretch as the animal prepared to leave. Bed in area where brush slightly denser than average, and concealed well by grasses on one side. Photos next day after some melting (bottom of one part melted out). Odor of fox evident on day it was made, not detected following day.

17JA87. Red fox lope. Front feet bigger, back feet have rounder heels. Body held at an angle to direction of travel.

LF       RF                              

 o         o                     RH       LH

                                      o         o

4FE87. Fox at Willowbrook cached a short-tailed shrew, and apparently stopped by later to check on it.

6AP87. Willowbrook fox still present.

17AP87. I saw the fox.

27JE87. McKee Marsh area. A red fox passed just north of sawdust storage pile. In thin summer fur. Saw me as it came even with me, 50m away (I was standing, but still), and it ran into tall vegetation.

23DE87. Fox swam across Glen Crest Creek at Willowbrook several times in recent days.

3JA88. McDowell Grove Forest Preserve. Several pictures of newly excavated fox den, with rabbit remains at entrance. In gravel bank above floodplain of stream.

9JA88. The McDowell fox has used the river ice intensively as a corridor and for crossing (tracks especially heavy opposite den).

15JA88. Followed Willowbrook Back 40 fox’s wanderings through last night’s inch of new snow, Back 40. Nearly all the time in steady diagonal walk or trot. Relying on nose for clues? Occasionally deviated to investigate rose bush or brush tangle.

17JA88. Blackwell. Rain melting snow reveals a superabundance of meadow voles (also found 2 dead voles), near where kestrel had picked the one found on the 14th. Predators taking heavy advantage. Fox tracks all over.

23JA88. Alternative trot pattern, body straight with path of travel? McDowell. Even spacing throughout (within and between sets), 12 inches separating (slow lope? But so close together?). Travel left to right.

 LF       LH                   LF       LH

  o        o                         o         o

            o        o                          o        o

           RF       RH                     RF       RH

Foxes highly active last night (rabbits, too). 1″ snow fell just after sunset.

28JA88. Fox tracks in normal walk separated by 14-18″. After 2 full days of no fox tracks, suddenly after last night the Back 40 is filled with them.

29AP88. Fox seen at Pratts Wayne Woods Forest Preserve. Stopped many times to look back at me as it ran away.

10SE88. One seen Herrick Lake F.P. Seemed weak, or perhaps simply expected me not to notice it there.

2NO88. Willowbrook. Tracks have returned to Back 40, after disappearing during summer of marsh excavation and nature trail construction.

15JA89. Red fox tracks at Herrick Lake Forest Preserve: one fox’s set had a pattern for a long distance, on cleared path with ice and a thin snow cover that had partly fused to it, of a mix of walk and trot, i.e., two walking steps and a trot step.

24MR89. Winfield Mounds, tracks. Red fox moved from walk to trot (body angle version). Step increased from 16″ to 18-19″, and more on toes.

22JE89. Scats in Willowbrook Back 40 packed with mulberry seeds. The berries first ripened within the past week.

7SE89. Red fox tracks near marsh. Fox also crossed Park Boulevard last night.

8SE89. Back 40, fox walking stride average about 16 inches, heel to heel.

19NO89. Tracking coyotes in half inch of snow that fell last night on McKee Marsh area. Ponds frozen. Coyotes’ activity heavily on and around them. Frequent rolling, sometimes in urine. Fox tracks absent from wide area I walked in N. Blackwell. Were common before; have coyotes driven them off? (In late 90’s, foxes resurging; researchers say mange took them out).

20NO89. Red fox tracks, Willowbrook, soft soil (but true track size) 1 5/8L x 1 3/8 W.

14DE89. Willowbrook. Fox direction of travel when track partly filled with snow: slides foot in at an angle, lifts it straight out. Covered a lot of ground last night. Played a while with the caged fox. Below 0°F last night. Rabbits, mice and a muskrat active.

16DE89. McDowell. Foxes and coyotes present. Foxes about 12-16″ between steps in walk, coyotes 15-20.”

19DE89. Willowbrook. Fox carried stiff dry weed stem 1.5 feet long for some distance, dragging end in snow. Play? Were mink doing same at Herrick and McDowell last winter?

21JA90. West Chicago Prairie, on Prairie Path. Fox slow lope, maintained considerable distance. 9-14″ (variable) between footprints, tend to be greatest from the Left front to the pair of tracks. Gait developed out of a trot, body-angle version, with 11-12″ between pairs of tracks and 2″ (along axis of travel) between the members of a pair. The slow lope appears to be a common gait along here today, either an individual preference or controlled by the quarter inch of snow that had fallen earlier.

          LF       LH                  

            0         0                      0        0

 0                     0          0                    0

RH                   RF                              

26JA90. Willowbrook. 4 inches of snow dumped in heavy wind yesterday. Last night wind calmed. Sticky snow on all plants. Mice and foxes, some rabbit activity. Fox taking longer (16-24″) walking steps. Lifted leg to mark (male?). A common slow lope pattern, so similar to the diagonal walk as to be almost indistinguishable in this snow depth. Appear to be LF, RF+RH, LH. Space between sets of 4 tracks slightly greater than spaces between. Travel left to right:

 o                    o                    o                    o

          o  o                                      o  o

(actually, slightly longer hole in snow where right feet are close together)

22AP90. Winfield Mounds. Tracks near SE corner of preserve, near houses.

26JA92. Hidden Lake. A red fox in forest bedded for a time atop a fallen log, bed 8″ diameter at bottom, 12″ diameter overall. Fox removed a bit of a burdock bur with some hairs. Bed 2.5 feet above ground, on a hillside. Fox had walked along top of log to reach the spot.

From 1993 to 1997, red foxes were scarce in DuPage County. I don’t remember seeing any on the preserves during that period, and essentially no signs. Coyotes, meanwhile, became abundant. Beginning in 1998, I began seeing red foxes again. Coyotes remained abundant.

1AP00. Red fox scats on Heritage Trail, Morton Arboretum, near its southern boundary with Hidden Lake Forest Preserve.

In the 2000’s I seldom have encountered red foxes or their signs. Based on reports from phone calls to the forest preserve district, and occasional sightings of my own, I have the sense that red foxes now are mainly animals of residential neighborhoods, and are much less common than they once were in the county. Their place on the preserves has been taken by coyotes.

Eastern Chipmunk Dossier

by Carl Strang

 

The first chipmunks began to show themselves at Mayslake in the second half of March. Today I’m sharing my dossier  on the species. The codes are my representations of dates, the day followed by my month code, finally the year. The dossier was established in late 1986 or early 1987, entries added thereafter as needed. Since this one is relatively long, I have edited out some entries that simply give date and location observations.

 

chipmunk-1b

 

Chipmunk, Eastern

Lives in underground burrows; often plugs some entrances with debris. Vocalizations include “chip-chip-chip…” and chip-trill alarm “chip-chip-churrrrr.” Single “chip,” birdlike. Lives in forests and at forest edges. Also savannahs with some bushy cover. Can climb trees but usually forages on ground. Disappears for most of the winter, apparently plugging burrows. In presence of red fox (passing with another chipmunk dead in mouth), they gave a couple quick chips and were silent (MY86). I have had one “singing” while watching me.

6MR87. Newly opened chipmunk burrows in Willowbrook Back 40 the first signs of that species this year.

7AP87. Chip-trill at my approach produced response by gray squirrel: jumped onto low branch, looking alert.

10MY87. Chipmunk pursued by another, stopped with 3 high chips in a lily-of-the-valley patch within forest at North Blackwell, as the other turned back. Then the first one came out into deep oak litter and foraged. Frequently stuck head under leaves, a few times burrowed completely under. In one spot munched several invertebrates, only remains found later were part of a striped slug (1/3 of head end missing, recently bitten off). Ate at least 3 items, 2 appeared to be slugs, the other had legs.

23AU87. When running hard (e.g. crossing open space), hold tails vertical. One ate an acorn.

27AU87. Chipmunk drank from small pool: barely put mouth in water, remained still until done except for rapid fluttering of cheeks. It drank for about 20 seconds.

16AP88. Morton Arboretum. An old chipmunk’s hoard of acorns, now reduced to shells, inside the hollow root of a dead oak. The top of the root has rotted away, exposing the shell fragments.

29MY88. Hartz Lake, in woods. A chipmunk saw me move my arm laterally, gave 3 chips increasing in speed, and ran. Immediately 2 jays feeding on the ground flew up. They were 40-50 feet away.

4AU88. Willowbrook Back 40. Chipmunks active. Early estivation this year because of drought?

 

chipmunk-2b

 

31AU88. Willowbrook Back 40. Chipmunk 15-20 feet up, on slender branches of a 25-30-foot-tall black cherry, cheeks full.

1SE88. Willowbrook. Active past couple weeks, sniffing over the ground and quickly climbing high into cherry trees (and quickly down, head-first), filling cheek pouches.

5MR89. A cold (20F) windy day, ground frozen with crusted snow layer, yet some chipmunks active in a firewood pile at McDowell.

12MR89. Hartz Lake. An area hotly contested by 4-6 chipmunks, in low wooded area with many fallen trunks, standing hollow stems, and brush. Much chasing, sometimes turn around and chase back. Often make squeaking calls. I stalked successfully within 5 feet, lay down with arm alongside log for a while without being recognized, but none came close enough to touch (they had pretty much settled down by then).

 

chipmunk-3b

 

8MY89. A foraging chipmunk appears to find its food mainly by smell, sticks nose into vegetation with eyes closed, takes object with mouth and pulls out to eat.

31AU89. Chipmunks producing lower “chuck” call with great horned owl above.

7SE89. Chipmunk eating a small (less than 0.5″ diameter) red crabapple fruit.

28JE&1JL90. Chipmunks up in mulberry tree canopies (15 feet up) at Willowbrook and West DuPage Woods (mulberries ripe more than a week now).

Late MY90. Hartz Lake. Chipmunks foraged by nosing and digging among oak leaf litter in area of scattered trees.

30AU90. Chipmunks in cherry trees, Willowbrook.

5SE90. Willowbrook. Chipmunk tracks, clear, in fine mud. 3-lobed heel. Hind tracks less clear; pushing off harder from hind feet.

 

chipmunk-track-sketch

 

18JE91. Chipmunks on ground, Willowbrook, stuffing themselves with fallen mulberries at midday.

13SE94. Chipmunks climbing high into box elder trees and eating seeds, this week. Go out to the finer twigs, look a little clumsy but undaunted.

5AU95. On Red River in WI, mink hunting along shore. As it came close, chipmunks gave a single loud “chip” apiece and were then silent (see red fox entry, in MY86).

Summer 1999. I listened and watched daily, and did not detect a time when there were no chipmunks active. No estivation, or overlapping among individuals?

2MR00. Willowbrook. First chipmunk of the year seen.

15MR00. Willowbrook. One chipmunk chasing another.

12NO01. Chipmunks still foraging, on a sunny day in the 50’s, Morton Arboretum.

Mink Dossier

by Carl Strang

 

Last weekend I paid a visit to Fullersburg Woods Forest Preserve. I was surprised to find mink tracks, representing at least 4 individuals, all over the preserve. In the three years my office was there I had seen tracks only once or twice per winter, with only one individual in each case. Today I thought I would share my entire dossier  on that species. Here’s a photo of the critter, then on to the dossier.

 

212-mink-1b

 

We saw them frequently in daytime when floating the Tippecanoe River in Indiana when I was a child. Usually they ran along the shore or appeared in drift snags. Occasionally one dove under the water. I first identified the tracks at Fullerton Forest Preserve in 1985. Five toes each foot, very round appearance in sand or mud, larger than one would expect for the size of the animal (paddle feet for swimming). Winter tracks in snow at McKee Marsh, Blackwell Forest Preserve, early 1986: nearly all in trot or lope patterns (actually a bound with offset feet). Dropped to straight bound once when passing through an area of deeper (6-8″) snow.

25MY86. One observed traveling through a small, cattail-choked waterway at Herrick Lake Forest Preserve. Moving, body seems to flow, even on dry land. It saw me, turned around, and after going back upstream 10 yards or so climbed back over the embankment that separated the smaller waterway from a larger marshy area.

28NO86. At Culver Fish Hatchery:

 

mink-track-drawing-1b

 

11JA87. Waterfall Glen Forest Preserve, Sawmill Creek near mouth at Des Plaines River. Mink dug leopard frog up from somewhere beneath trunk of fallen tree resting on bank. Mink carried frog on a twisting path before digging hole in the 8″ snow and depositing the frog without filling hole. Frog not yet frozen, tracks very fresh. Tracks restricted to area around that tree, with many burrow-like holes entered. Mink has shelter there or else emerged from and entered river under tree roots.

21JE87. Tracks crossing muddy road at Herrick Lake Forest Preserve. Photos: in first picture, left track 1.125″ long x 1.25″ wide, right 1.375 long x 1.25 wide. Stride ~13″ in bound. In second picture, front? definitely smaller, hind? aligned more with previous set. If front’s supposed to be larger, animal turned right. In drawings, #1 1.125W x 1.25L; #2 1.25W x 1.125L; #3 1.25L x 1.125W; #4 1.25W x 1.0625L.

 

mink-track-drawing-2b


27JE87. I was picking chickweed in a rank patch at McKee Marsh at about 9am as a mink passed. It was so buried in the chickweed I thought it was a woodchuck, but it seemed to be shaking plants less and making less noise than I would expect, and moving faster. Caught glimpse of its hindquarters and tail. Had passed within 5 feet of me as I stood still. Was moving toward woods, away from marsh, ~40m from marsh.

16JA88. In shallow snow over ice of river, mink did much bounding in travel (mostly). In bound may lead with one side so that some tight “lopes” are actually bounds. Several photos to illustrate this, after fox trot photos. Photos of mink gallop. Sets 2 feet separate, and each set well spread out (bounds on the same ice were 16-18″ apart).

17JA88. See meadow vole entry.

23JA88. McDowell Forest Preserve. Mink trail wound in and out of fence row along edge of brushy/small tree area and grassy field, with some sorties into either but no more than 10m from boundary. Once went down burrow, once apparently slid on belly. Last photo on roll shows separate front and hind feet (otherwise mainly bounding with hind feet landing on fore). FF ~1.125 x 1.125, HF ~1.5 x 1.25W. Entered and exited several more holes. Eventually went into the river. These tracks were made early last night: some in water that later froze; also, I had noticed crystals had formed in tracks, when I tried to blow snow away. Backtracking: had climbed into low (3′) crotch of large willow, crossing to the other side before jumping down. A tangle of trails where a very small stream (6″ wide) flows into river. If the mink I had followed went no farther, its evening home range included ~0.25 mile of shoreline and inland up to 100m.

I picked up another trail consistent with age of first, and followed it back inland, through logs, in and out of holes, etc., until it led to where mink had pulled out of water, on other (N) side of parking lot. Toward end, at least, mink mostly led with left side, though it sometimes led with right.

13FE88. I spotted mink tracks from U.S. 31 between S.R. 110 and Rochester, IN, got pictures. Had tunnels and slides.

 

mink-hieroglyphics-b

 

15JA89. A mink at Herrick Lake Forest Preserve was dragging something, sometimes leaving only a thin mark atop the bounding set, sometimes a wider (3/4″) mark that was continuous between and over sets. The mark was on top of the tracks, therefore following them, but was on the right side while the hind feet were on the left, implying that the marks weren’t made by the tail. (See red fox 19DE89). Last month at McDowell, I found where a mink had apparently dragged something for a considerable distance, but this time the dragging was continuous and the heavy mark was more than an inch to the left of the bounding tracks. In both instances the animals were moving along the edge of a frozen lake, on the ice.

6JL90. At Hidden Lake Forest Preserve, the largest mink I’ve ever seen, moving from a perennial-old field area backed by forest into the new large marsh area.

5AU95. Red River, WI, near kayak put-in. Mink hunted along shore, on land, within 8 feet of water, moving downstream. Sniffed ground, looked into vegetation. Sometimes stopped, sometimes diagonal walked, sometimes bounded, covered 150 yards of shore before it caught a large crayfish and carried it inland. Chipmunks responded as they did to red fox at Arboretum.

8AU98. Red River, WI. Across from lunch area at first drop: beneath a group of river’s edge white cedars was an old stump with a 4″ hole. Nose of my boat touched a foot away from it, and a mink’s head appeared. I sat still and watched it for more than 3 minutes. It mostly sniffed, looked around, yawned a couple times, stepped its front legs out to sniff my boat, ducked back in a couple times.

30OC99. Dead mink, not dead too long, red blood still around mouth but no other sign of damage, on a mudflat near a stand of cattails at Fermilab. Internal injury, or self-biting during convulsions associated with illness?

21FE99. In the 3 days since the last snow, no mink tracks at McKee Marsh. Was the dead one at Fermi last fall the sign of a diseased, crashing local population?

14OC00. A mink seen at Fermilab, not far from the location of last year’s dead one. 80 yards from water, in upland old field.

31AU01. Algonquin Park, Ontario. A small one, probably an adult female, using the boardwalk of the Spruce Bog Trail, in the bog, to travel on. I was standing still, she did not notice me until 15 feet away, then turned around, went back a few steps, and got off the trail into the bog, disappearing quietly into the dense vegetation. When hunting, she sniffed frequently, and occasionally looked to the side.

20AU05. A mink and I startled one another in the early afternoon as I walked the pond in my dragonfly monitoring route at Songbird Slough. It made a brief loud squalling sound as it turned and ran away, a sound very similar to that made by a complaining juvenile raccoon.

4SE06. A mink visited my camp on the last night of my Georgian Bay sea kayak trip. I was able to get some photos.

 

214-mink-3b

 

14FE09. Fullersburg. Mink tracks are all over the preserve on the morning after a 1” fresh snow over bare ground. There appear to have been 4 individuals active last night: 2 traveling together between Sycamore Peninsula and the York Road bridge, one on and around Willow Island (on both sides of Salt Creek), and one in the west part of Butler Woods. This is in marked contrast to the rare observations of single individuals at Fullersburg over the past three years. Recovering from decimation by disease?

Sketching Mayslake’s Trophic Structure

by Carl Strang

 

 

As I familiarize myself with an area, there are several big conceptual nets with which I try to comprehend that place. These lack fine detail, but provide first approximations that can be filled in as I learn more. One conceptual frame for an area is its general topography and drainage pattern. Another is the general human history and influence on the land. A third is the mosaic of vegetation communities. A fourth is the geology. Today I want to focus on yet another frame, the trophic structure. This is a broad-brush first stage in constructing a food web. The trophic levels of an ecosystem are the steps through which energy “flows” (the quotes are a field ecologist’s recognition that abstract food pyramid diagrams, and the arrows that connect food web elements on the page, cover up a certain amount of desperate flight-and-chase, crunching, and screaming. All our lives continue at a cost, but I digress).

 

In earlier posts I have documented some of Mayslake’s animal life. The top predators mentioned already include coyotes and mink. A day seldom goes by without me seeing a red-tailed hawk or two. I also have seen tracks of great horned owls, and the Mayslake staff have observed these birds at that preserve for years.

 

Great horned owl tracks, Mayslake

Great horned owl tracks, Mayslake

 

 

Note that in this photo, the great horned owl tracks are farther apart than in the photo I took on the Christmas bird count. This is the more typical spacing, but again there is that odd asymmetry in the toes.

 

 

Mayslake’s part-time predators include raccoons and skunks, among others.

 

Skunk tracks (far right), Mayslake

Skunk tracks (far right), Mayslake

 

On a smaller scale, I have seen tracks of short-tailed and masked shrews, which are predators of small animals including invertebrates but also mice.

 

Common plant-eating animals at Mayslake include deer, mice, voles, squirrels, chipmunks and cottontail rabbits. There are also the wandering winter birds eating seeds (as in the paper birch account).

 

Rabbit trail, Mayslake

Rabbit trail, Mayslake

 

 

Over 50 kinds of trees, shrubs and vines, along with uncounted herbaceous plants, are the preserve’s primary producers, solar energy harvesters that form the foundation for the whole trophic shebang. In the warm months, each kind of plant hosts several insect consumers that in turn are food for predators including an influx of migrant nesting birds.

 

And let’s not forget the scavengers. Some of the animals listed already, the coyote and skunk for instance, along with opossums such as the young one whose tracks I saw in the southern part of the preserve recently, are happy to clean up the odd dead carcass they encounter.

 

Mayslake is not a huge property as forest preserves go, but it’s big enough and diverse enough in vegetative structure to support a complex community for which I have here provided only the broadest of introductory sketches. More detail to come.

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