Goose Roost Patterns

by Carl Strang

A severe winter storm in early December quick-froze the surfaces of ponds, marshes and many lakes. This was disappointing, as I hoped for waters to stay open longer than they did last year. On the other hand, the repeat may allow me to get a sense of how consistent the behavior of wintering geese will be under similar conditions.

One departure from last year was evident on December 12 at the Blackwell roost. About 1200 geese were roosting on the frozen surface of Silver Lake.

Among them was one bird with the orange neck collar that marks it as a goose that nests in the Hudson Bay region.

I am not sure why these geese roosted where they did, given the availability of open water in last year’s roosting area on the nearby stream, where I counted an additional 2300 birds (including 3 more with orange collars).

Otherwise, patterns on that day were familiar. Around 700 geese were at the McDowell roost, 2500 at Hidden Lake, and geese were absent from frozen Herrick Lake and Rice Lake at Danada Forest Preserve. At the moment, counts are higher at all three of these roosts than my highest counts last year (which were 3000 at Blackwell, 500 at McDowell and 880 at Hidden Lake). The geese were moving out in familiar directions from the roosts to feed.

Whether these numbers will stay so high remains to be seen. On the days following the storm, which affected most of eastern North America, many geese from farther north were passing high over DuPage County and, according to reports from birders, continuing on at least to central Illinois. If last year’s pattern of severe cold and freezing roosts continues, the numbers of local birds will drop.

A respite of two warm days opened up the Blackwell roost and part of Silver Lake. On December 15, I found geese again on that lake, resting on the edge of the open area.

The main roost pond above the dam, just north of Silver Lake, also had opened.

I was able to photograph one of the collared geese from close enough range to read its collar.

The identification code for this individual is M8R1.

I have passed this information on to the Canadian Wildlife Service. The weather is turning cold again, so the possibility remains that DuPage geese will be forced to shift south.

Winter Comes to Mayslake

by Carl Strang

November had been unseasonably warm. I heard Carolina and Allard’s ground crickets singing on December 1, the latest I have heard any singing insects in DuPage County. But it wasn’t to last. A major winter storm, complete with strong winds, a significant snowfall, and temperatures dropping to the single digits Fahrenheit, arrived in the second week of December.

Mayslake Forest Preserve, like most of the eastern U.S., received its blanket of snow, though only 2-3 inches accumulated locally. The low temperatures froze the lakes. Coyotes again could use the ice for quick short cuts.

The snow revealed that the coyotes were covering the entire preserve, though apparently singly; I saw no signs of tandem hunting. Birds in evidence were mainly consumers of seeds, like these mourning doves,

and this cardinal,

here caught in the act of reaching for fruit.

Black-capped Chickadee Dossier

by Carl Strang

I have mentioned black-capped chickadees from time to time in this blog, most notably when introducing the topic of mixed flocks. Today I want to share my dossier on this species. In my dossiers I try to summarize what I know of a species from my own observations, as opposed to information from the literature or other outside sources. I began writing the dossier in the mid-1980’s. Observations begin with my date codes.

Chickadee, Black-capped

Ca. 1979. I remember sitting on the hawk watch at Reineman Sanctuary in PA in fall and watching as a sharp-shinned hawk zipping along the ridge suddenly turned its course so as to enter the tree canopy and caught a chickadee.

Boiling Springs, PA, 1980. A pair nested in hollow Ailanthus branch. One bird was electrocuted by a nearby electric fence. The other completed incubation and at least began to rear the brood alone. “Cheeseburger” call (more formally known as the fee-bee call) used early as apparent territorial signal.

Lombard, IL, 1981. A pair nested in a wren house, raised a brood, then returned and raised a second brood in the same house. In both cases, the pair traveled the neighborhood with their groups of fledglings.

Maple Grove Forest Preserve (F.P.), 1986. A pair was cleaning out an old cavity in a 10 foot snag in the maple forest. The excavating bird periodically removed beaks full of sawdust. Other bird remained nearby, giving occasional “chickadee” contact call.

Meacham Grove F.P., 24MY86. For the first time, I saw a chickadee taking advantage of tortricids hidden in folded leaves. One individual moved from one folded leaf to the next, vigorously tearing them open. I expected to see it more frequently than I have, given the lack of other birds with the appropriate foraging behavior in their repertoire, and the abundance of this food resource.

Willowbrook F.P., 1984-86. Chickadees have broods in the wooded riparian strip each spring. One pair appears to control the entire 1/4 mi. X 100-foot strip. Groups of more than 2 chickadees stay together through the winter. “Chickittaperk” vocalization appears to be an interspecific agonistic (dispute) display.

Chickadees weren’t common in Culver, Indiana when I was growing up. I remember being pleasantly surprised that a pair was present, nesting, at Miracles’ house in summer. This implies they were more easily seen in winter, at the feeder. Old trees and branches were scarce in our neighborhood.

Alarm call: one used a sharp “chiburr,” another answered with the same call.

11FE87. Willowbrook. Widely scattered chickadees in the Back 40 old field are maintaining contact mainly via the feebee call.

28FE87. A group of a half-dozen chickadees in trees: much sneeze-calling and chick-chick-chick-chick, but few chickadee calls, with much chasing and displacement. Later, many individuals made chickadee calls from widely separated perches. Then a period of silence followed.

14MR87. Maple Grove F.P. Seven chickadees moved together with a mix of chickadee and sneeze calls, occasionally briefly chasing one another. The group spread out widely, then used very high-pitched brief “cheeks” for contact.

29AP87. Chickadee caught adult noctuid moth, pecked body (scales puffed into the air), removed wings one at a time and they drifted to the ground, landing at least 3 feet apart.

1JL87. Willowbrook F.P. Chickadee pecking at mulberries.

10SE87. 0.5-3 seconds per perch in foraging, flying or hopping a few inches to 6 feet or occasionally 10 feet between perches, acrobatic hanging or hover-gleaning, pecking at dried leaves, turning and lowering body almost to upside down position to peer different ways.

13SE87. At West DuPage Woods F.P., several chickadees in a mixed flock with a redstart and a bay-breasted warbler.

17JE89. A broad-winged hawk callied repeatedly, in north end of Maple Grove F.P. Jays, flickers and grackles were highly agitated, flickers the most continuously vocal with “keels” every 2 seconds (2 birds). Grackles gacking frequently, too. A great crested flycatcher near, also vocal, but not clearly in response to the hawk; same with chickadees. Robins definitely disturbed, with nervous dee-dee-dee’s every 20 seconds or so. Jays in bursts, with several birds mobbing.

10JE90. Warrenville Grove. Chickadee saw me at sit near edge of woods. Alarm call “chicka-chicka-…(rapid)-dee-dee-dee”

3JL90. Chickadee plucked 2 unripe (white) mulberries from the branches. Dropped the first, then went for the second. Worked on it several seconds, holding it against a twig with its toes. I couldn’t tell if it ate the whole berry or just extracted seeds. Suspect latter.

7SE90. 2 chickadees eating dried crabapples, eating, pulling out and eating little bites.

30SE90. Chickadee and downy woodpecker eating poison ivy berries at Ann’s business property near Lafayette.

8FE00. Chickadees heard singing for the first time of the year at Willowbrook, and continuing in the following days. Also vigorously chasing each other this day, with agonistic vocalizations.

10FE00. Chickadees singing (feebee song) at Willowbrook.

1AP00. Morton Arboretum, Heritage Trail. A mixed flock with at least 1 brown creeper, 2-3 chickadees; juncos and robin in area. Chickadees longer on each perch than golden-crowned kinglets observed yesterday. A lot of looking around, not so constantly moving between perches, and making larger jumps between perches, 3′ common. Later, another association of chickadees, golden-crowned kinglets and a white-breasted nuthatch. These mixed flocks stand out because after going through a long segment of forest path where there are essentially no birds, suddenly there are many at once of several species. Again, chickadees sitting longer in one place and moving farther between perches. All moving together in same direction through forest, and moved away from me as I observed them. Later still, a couple of chickadees without associates. Perhaps this is the kind of observation that led to the local core species idea.

25JE00. This spring I have observed 3 chickadee groups with parents and fledglings, one at the Arboretum on 1JE, one yesterday at Willowbrook, and a third in another part of the Arboretum today. Instead of being spread out, in each case the groups were clustered in a small area no more than 20 feet in diameter, and they moved only very slowly. Feedings were frequent, so apparently the parents directed or led their young to food-rich locations.

11MR01. A chickadee at Timber Ridge Forest Preserve with a variation on the fee-bee song: the “bee” syllable is repeated, and each syllable has the usual hinged quality, i.e., “fee-bee-ee-bee-ee.”

More recent observations have focused on the role of black-capped chickadees in mixed flocks.

29AU01. Algonquin Park, Ontario, Mizzy Lake Trail. Flock 1: Golden-crowned kinglets, a young-of-the-year black-throated green warbler, black-and-white warbler, black-capped chickadees. Flock 2: At an edge between mixed forest and a lake. Black-capped chickadees, several black-throated green warblers (appear to be sticking together to form their own group within the flock), at least 1 blue-headed vireo, 1 female or young blackburnian warbler, 1 chestnut-sided warbler, and 1 Tennessee warbler. The black-capped chickadees are very abundant here, the most apparently numerous birds in the forest (because of their frequent calling and frequent presence). It is easy to see how migrant birds accustomed to forming mixed flocks with them here in the north could attach to resident birds they encounter on the trip south. Flock 3: Black-capped chickadees, Swainson’s thrush.

30AU01. Algonquin Park, Bat Lake Trail. Flock 1: Black-capped chickadees, a black-and-white warbler, the latter singing. Flock 2: Black-capped chickadees, red-breasted nuthatches, golden-crowned kinglets, 1 or 2 black-throated blue warblers, at least 1 Tennessee warbler, yellow-rumped warbler. The first three species are the vocal ones. These flocks are distinctive: you go for hundreds of yards seeing or hearing no small birds, then suddenly there is one of these diverse groups in a small area.

31AU01. Algonquin Park, Spruce Bog Trail. Flock 1: Yellow-rumped warblers, black-capped chickadees, red-breasted nuthatches, golden-crowned kinglets. Do more northern birds, living in more open forests, either not have chickadees to associate with, or perhaps the scattered trees (if they are) remove the advantages of mixed flocks? See if it’s true that the non-mixed-flock species tend to be more northern.

12SE01. Willowbrook. Flock 1 around west end of cross trail. 2 chickadees and 1@ of black-throated green, magnolia, Tennessee (sang a couple times), and 1 unidentified species. Flock 2 near the NW corner of nature trail, a magnolia warbler apparently alone.

13SE01. Willowbrook. A large but difficult to view mixed flock near office building: 3 chickadees, 2 redstarts, a blackpoll warbler, a red-breasted nuthatch, and many others.

14SE01. Willowbrook. Flock 1 around NW corner of nature trail: redstart, chickadee, downy woodpecker, Tennessee warbler, black-throated green warbler, magnolia warbler, red-eyed vireo. Flock 2 between eastern part of animal exhibit and bridge. Chickadee, 3 redstarts, downy woodpecker, blackpoll warbler (it is possible that the one seen earlier joined this flock; it was near this location).

17SE01. Willowbrook. Flock 1: 3 chickadees, 1 redstart, others perhaps; near west end cross trail. Flock 2, base of savanna, 2 palm warblers only. Flock 3, brush area east of Nature Trail, 2 chickadees only. Flock 4, another part of same brush area, 2 chickadees, a magnolia warbler, 1 other unidentified.

19SE01. Willowbrook. Flock 1, east exhibit area to bridge: 2 chickadees, 1 black-throated blue warbler, 1 redstart, possibly others. Flock 2, west end cross trail: staying around berry-feeding robins, waxwings and catbird, with no chickadees around: a black-and-white warbler, 2 downy woodpeckers, a redstart, a blackpoll warbler, possibly others.

25SE01. Elsen’s Hill, plateau above river. Flock 1: at least 8 vocal, active yellow-rumped warblers, and a ruby-crowned kinglet. Flock 2, very large and diverse, only some individuals identified: 2 chickadees, black-throated green warbler, blackpoll warbler, 2 Nashville warblers (1 low in an aster thicket another in low tree branches), downy woodpeckers, a parula behaving like the Nashville, 2 redstarts, a chestnut-sided warbler.

26SE01. Willowbrook, between bridge and animal exhibit. 2 chickadees, and at least one @ of vireos (Philadelphia, red-eyed, yellow-throated), warblers (Tennessee, magnolia, parula, black-throated green), scarlet tanager, red-breasted nuthatch.

27SE01. Willowbrook. Flock between bridge and exhibit fence. 2 chickadees, 1 Tennessee and 1 magnolia warbler.

30SE01. Fox River and Island Park, Batavia. Many yellow-rumped warblers spread out all over, some hover-gleaning, some flycatching, others reaching for poison ivy berries. With them, a chickadee, a male Cape May warbler in the top of a silver maple, very active in the short time I saw it.

14SE02. Elsen’s Hill. I walked for several minutes, seeing apparently independent Tennessee warblers (2 together) and a Nashville warbler before encountering a large flock. This flock seemed to be changing composition over time, i.e., after my initial observations I walked a short distance away, then returned, and when I came back, some birds were the same but there were several new ones, as well. Later, after following the flock for 50 minutes or so and losing them in a direction I did not want to pursue in the brush, I returned to the starting point and a small mixed flock was there, with some of the birds I saw initially (apparently, none were marked of course) and a couple added ones. Initial group: a blackpoll warbler, 2 red-eyed vireos, 2 redstarts, an essentially silent chickadee, a black and white warbler, a Tennessee warbler, a Swainson’s thrush, a female or young black-throated blue warbler that was the only flock member calling consistently, all foraging in brush understory within 15 feet of the ground (the redstarts were the only ones consistently going above 10 feet; this was after 9 a.m.). Flock after my return: golden-winged warbler (like the redstarts, up higher, and very active, including flush and pursuit), a male and 2 female or young black-throated blue warblers, 2 Tennessee warblers, a black-throated green warbler, 3 redstarts, 2 blackpoll warblers, a black and white warbler, a blackburnian warbler. After it had warmed up some, later, a magnolia warbler foraging 20-25 feet up and the other birds also have gone higher. Doing a lot of reaching, and spending much time looking from each perch. At 10:45 I returned to the starting point: 4 noisier chickadees, 2 red-eyed vireos, a blackpoll warbler, a male redstart, a magnolia warbler, all except the chickadees foraging higher, throughout the tree canopies. Also a downy woodpecker, black-throated green warbler, Swainson’s thrush.

25AU08. Fullersburg Woods. First mixed flock of the fall migration has 2 chickadees, a downy woodpecker, a Tennessee warbler and a Canada warbler.

28AU08. Fullersburg Woods. Mixed flock just S of Willow Island bridge: 2 chickadees, 2 Tennessee warblers, 2 magnolia warblers, a gnatcatcher.

29AU08. Fullersburg Woods. Mixed flocks: One with four chickadees, two Tennessee warblers, a magnolia warbler and a black-and-white warbler. Also, 2 Tennessee warblers together apart from mixed flock. At mid-day a mixed flock near the junction of trails with 3 chickadees, 3 Tennessee warblers, a white-breasted nuthatch, a magnolia warbler, a parula. Chickadees were doing a lot of hanging upside down, Tennessees less acrobatic running along tops of branches and reaching, magnolia and parula more rapid movements, hopping between branches, nuthatch on bark, all in top half of canopy.

13SE08. Kettle Lakes Provincial Park, Ontario. Large, mixed flock in an area around 75 yards in diameter: at least 2 black-capped chickadees, 5 golden-crowned and 4 ruby-crowned kinglets, 4 yellow-rumped warblers, 2 red-eyed vireos, downy woodpecker, black-and-white warbler, black-throated green warbler, redstart, red-breasted nuthatch. I’m hearing white-throated sparrows, but they seem all near the ground rather than up in the trees with the others. Weak songs from ruby-crowneds, the black-throated green and the black-and-white. This is mainly an area of aspens with some jack pines. Mixed flock: at least 2 chickadees, at least 2 golden-crowned kinglets, 2 ruby-crowned, and a yellow-rump. Aspen grove again with some jack pines and a couple white pines.

15SE08. Nagagamisis Provincial Park. On trails, encountered a little flock of at least 7 ruby-crowned kinglets. Nothing up with them first time through, but white-throated sparrows lower down in that area (on the way back a chickadee, a brown creeper, 3 golden-crowned kinglets and a Swainson’s thrush added). Birds have been few, and I cannot discount the possibility of an association of the white-throated sparrows with this group. On the Time Trail, balsam fir the dominant tree with plenty of white spruces, some black spruces, white cedars, paper birches. Another mixed flock with at least one chickadee, 2 ruby-crowns, 3 golden-crowns.

21SE. Mayslake. A mixed flock at edge of Area 9 and grounds containing a black-throated blue warbler (new preserve species), black-throated green, 2 redstarts, 2 blackpolls, chestnut-sided, Nashville, black-and-white, magnolia, and a chickadee.

The Grebe and the Mallards

by Carl Strang

For more than a week, a migrating pied-billed grebe stayed on May’s Lake in late November.

This bird was constantly in the company of a group of mallards. Even when the ducks were standing on fallen logs near shore, the little diving bird floated close by. Here the grebe is at the far edge of a feeding mallard group.

The ducks were diving for aquatic plants. Mallards are not very good divers. The splash in the following photo is characteristic of their inefficient plunges.

They stayed beneath the surface 3-5 seconds, which in the relatively shallow water was enough for them to acquire a snack. If I were a children’s book author, I might be inspired to write a story about how the grebe was lonely, made friends with the ducks, then taught them how to dive for food in exchange for their companionship. While that story has emotional appeal, I’m pretty sure none of it was taking place.

Notice how two of the mallards are taking a peek below the surface before diving. The area where they are feeding is only a little farther out from depths where they can get food by tipping up. Mallards don’t dive often, but do so occasionally when bathing or when chasing one another. I’m pretty sure the ducks would be diving for food even if the grebe weren’t with them.

So what of the grebe’s behavior? This is a fairly solitary species, except during the breeding season. They don’t travel in flocks, or even family groups. Young make their way south on their own, entirely by instinct. Nevertheless, a grebe wanting others to hang out with could find them, and wouldn’t need to affiliate with ducks (grebes are now known to be more closely related to flamingos than to ducks, thanks to genetic comparisons made at the Field Museum).

Pied-billed grebes frequently can be seen in the vicinity of flocks of diving ducks or coots on larger lakes during migration, and my impression is that this is more than a random association, though some grebes also are off by themselves. I think the affiliation probably is more like what we see in mixed flocks of migrant songbirds than a social expression. There is evidence that mixed flocks have two advantages for their members. First, they provide more sets of senses for detecting the approach of predators (and the lucky bird that first spots such an approach can place itself on the far side of the flock). Second, the activity of so many birds foraging in close proximity stirs up prey which may escape the individual that first flushed it, but then can be caught by one of the others. It seems likely to me that something like this is going on with the grebes, too.

Downy Woodpecker Dossier

by Carl Strang

This is another of my dossiers, a collection of observations that represents what I know about a particular species from my own experience. Following an initial description that summarizes what I remembered when I set up the dossier in the mid-1980’s, each individual entry begins with my date code.

Downy Woodpecker

This is an abundant, year-round resident of forested areas and savannas. They nest in small tree cavities. Feed by searching on small twigs up to the size of tree trunks, on shrubs, sturdier weed stems, occasionally on the ground. They crawl rather than hitch along. Voice a rapid whinny, individual tones mores musical than hairy woodpecker’s and lower in pitch; reminds me of a movie witch’s cackle. When feeding, they pick at twigs or flake bark. They do much pecking under bark edges, when foraging on a tree trunk. Nest in hollow branches or main tree stems.

30MR86. 2 male downy woodpeckers in an aggressive encounter. Frequent flicking of wings and spreading of tail. Assumption of posture in which body is upright and neck arched back so bill points straight up. Appeared to be trying to get above one another. Generally faced one another when in bill-up posture, and both did it at once. Red feathers conspicuous.

Late summer 1986. As a flock of ground-feeding grackles flushed at the approach of people, downies and jays at Meacham Grove Forest Preserve emitted contact calls, apparently as a final check of location and status before possible flight.

8MR87. Waterfall Glen Forest Preserve. Male appears to be exploring the acoustic properties of a white oak limb. Spiralling up it, drumming frequently. Full drum about 1 second, poor spots drummed 0.5-0.75 seconds. Repeatedly drummed fully the spots that gave the greatest volume and lowest pitch. As I wrote the above, I heard vocalizations. Three downies now in that tree. The drummer and a second, presumably its mate, chased a third which gave fragments of the whinny call. They held themselves flat against branches, tails fanned, and gave whinny fragments and a more chattering, flatter sort of vocalization. The third bird left, but a few seconds later I heard a brief drumming about 50m in the direction it had gone. The other two immediately flew in pursuit, and after a few brief whinnies all was quiet.

7MY88. Indian Trails area, Culver. One systematically probing and pecking bases of hickory buds, open with leaves about 1/4 expanded.

18OC88. Hartz Lake area, Indiana. A vigorous, repeated displacement of one individual by another, though they stick together.

7MR89. Extended confrontation between 2 male downies. Mostly jerkily hopped up small tree stems within 3 feet of one another, flicking wings almost constantly, approaching, withdrawing, occasionally expanding and flashing the red patches, changing trees together, occasionally getting out of sight of one another momentarily, overall appearance of jerky movement. After more than 5 minutes of this, one displaced the other several times in rapid succession, but then they returned to the jerky maneuvering, with occasional rests on opposite sides of the trunk, out of sight of one another. Before all this, one of them called repeatedly, loud single-note reps. Another bird (female? Not seen) called or drummed a couple times during this from at least 50 feet away.

26-31MY90. Hartz Lake area. A nest in a river birch, entrance 12 feet up. Both parents fed, about 10 minutes between arrivals for each parent. Young still small, faint cheeping voices. When screech owl family passed by early one morning, one adult mobbed at a distance with alarm notes.

30SE90. Downy woodpecker eating poison ivy berries near Lafayette, IN.

10FE99. Two pairs of downy woodpeckers are actively engaged in drumming, calling, displaying and chasing in an area that centers on the Willowbrook bridge but extends most of the way to the marsh in one direction, and up to the big willow near the marsh’s water intake pipe in the other.

23MR99. The situation has become very complex at Willowbrook and difficult to follow, with displaying and chases, drumming and calls going on all day. It appears that at least 3 pairs are involved, with the center of the activity between the creek and the center of the outdoor animal exhibit. A downy woodpecker also was drumming in the big cottonwoods in the center of the Nature Trail circle, the first I’ve noticed there this year.

29MY99. Maple Grove Forest Preserve. Young audible in nest.

5OC99. Willowbrook. Downy eating poison ivy berries.

23FE00. Willowbrook. Male downy woodpecker displaying toward female, body in a stiff posture, tail fanned, unusual chattering vocalization, following or chasing her, matches Stokes’ description of Bill Waving.

1-2JL00. Juvenile downies have large red patches on top of head.

27MR06. Downy woodpecker drumming is so rapid that individual strikes cannot be followed. Hairy woodpecker drumming very rapid, individual strikes can be distinguished. Red-bellied rapid but slightly less so.

2009. Mayslake. One successful nest was in a large weeping willow branch in the SE corner of the mansion grounds. Young were vocal for several days before fledging. There was at least one other successful nest on the preserve.

Another One Bit the Dust

by Carl Strang

Restoration work that clears ground, whether through controlled burns or brush removal, can reveal stories from the past in the form of skeletal remains. Last week Mayslake Forest Preserve restoration co-steward Jacqui Gleason showed me part of a skeleton exposed through recent brush clearing performed by Forest Preserve District staff in the prairie area near the stream.

Fuzzy brown feathers around the feet, as well as the size and proportion of the bones, identify the remains as belonging to a great horned owl.

I don’t have the skill to age the remains, either in the sense of when the bird died or how old it was. Most animals die young, so if I had to guess I would say this probably was a youngster that died in its first year. If so, it wasn’t from 2009. As I reported earlier, the most recent great horned owl nest on the preserve met with tragedy.

Miscellaneous Mayslake Events

by Carl Strang

November is moving along, and I have some observations to report from Mayslake Forest Preserve that characterize the season. First is a casualty of the migration.

Hermit thrush dead b

I found this hermit thrush on the paved path that runs along 31st Street at Mayslake’s north boundary. Probably hit by a car, the bird looks peaceful but sadly still.

Though I haven’t seen the animals themselves, deer have been active on the preserve lately. Here a buck prepared for the rut by attacking some defenseless sumacs in the north savanna.

Buck rub Mayslake 1b

Deer also have been frequenting the orchard on the mansion grounds, snacking on fallen apples.

Deer tracks & apple b

Finally, with the water table dropping during the recent dry spell, crayfish have had to tunnel down to keep pace with it, hence the new chimneys on their holes.

Crayfish chimneys b

These notes begin my second year at Mayslake.

Mayslake Species Counts

by Carl Strang

Earlier this week I completed my first year of observations at Mayslake Forest Preserve. Many of the posts in this blog, which also is approaching its first birthday, have shared pieces of Mayslake’s ongoing natural history. It’s appropriate to look back at what I have learned there so far. Today I’ll simply share some numbers, the counts of species I have observed on the preserve to date.

Barn Swallows b

Resident vertebrates include 14 species of mammals, 4 reptiles and 3 amphibians (though additional frogs have been observed at Mayslake by others in recent years). The bird species count is 130, many of which were migrants passing through. I saw evidence for successful nests, fledging at least 1 young, in the following 21 species: eastern bluebird, chimney swift, song sparrow, house wren, eastern kingbird, robin, northern flicker, blue jay, eastern phoebe (cowbird produced), chipping sparrow (cowbird produced), downy woodpecker, red-winged blackbird, red-bellied woodpecker, common grackle, black-capped chickadee, tree swallow, European starling, blue-gray gnatcatcher, Baltimore oriole, white-breasted nuthatch, mallard.

Banded hairstreak b

The insect species count is only 97 so far, but most of these belong to 4 groups to which I have directed most of my attention: 26 species of singing insects, 29 dragonflies and damselflies, 24 butterflies and moths, and 6 bumblebees.

Blazing star b

Likewise my attention to Mayslake’s vegetation has been limited to certain groups of vascular plants. These include 49 trees (including those planted by landowners prior to forest preserve acquisition), 23 vines and shrubs, and 184 forbs. I’ll elaborate the last a little by mentioning genera represented by 4 or more species: so far I know of 4 Asclepias (milkweeds), 6 Aster, 4 Erigeron (fleabanes), 5 Eupatorium (a diverse genus including Joe Pye weeds, bonesets, and white snakeroot), 4 Polygonum (knotweeds), 5 Ranunculus (buttercups), and 7 Solidago (goldenrods).

Cooper’s Hawk Dossier

by Carl Strang

It has been a while since I have shared one of my species dossiers. One of my practices is to keep records of what I have learned from my own observations of various species, as opposed to reading about them in other sources. Today I bring out my dossier on the Cooper’s hawk. In reviewing it I see that I have left out a lot of observations of this species, which has become common in the Chicago suburbs over the past decade or two, but those other observations would be much like the ones below. The observations begin with my date codes.

Cooper's hawk b

13SE85. Spring Valley Nature Center, Schaumburg. A Cooper’s Hawk pursued a frantic, cheeping young thrush in and out among the trees, in sharp twists, turns, and vertical climbs and plunges, for a good 15 seconds. Then the hawk broke off, and the thrush escaped. This took place in an old field between stands of trees. Could the cheeping have been a signal to the hawk that the thrush had plenty of wind? As soon as the hawk turned back into the woods, the thrush continued its flight over an open field.

2AP88. One passed through woods at Hartz Lake (in Indiana), occasionally calling “kip.” Flew and perched, flew and perched its way across woods.

12MR92, McDowell Forest Preserve. A Cooper’s flew, northerly, high above woods. Pursued by a crow that occasionally swooped at it, but the hawk itself was nearly crow-sized, and it often turned and flew at the crow. Flight faster and more twisty then, but the crow turned to pursue the hawk when the latter resumed its path. Three such cycles observed.

18AP92. Hartz Lake. Pair of Cooper’s hawks hanging around a clearing in the woods, often calling: a wild-sounding, almost woodpecker-like “eh-eh-eh-…” (15-20 repeated syllables).

20AU92. Cooper’s chased a couple crows at Herrick Lake F.P., not seriously. They rattle-called afterwards.

18MR99. An immature plumaged Coopers appeared, hung around the Willowbrook riparian area (SE corner of preserve) for the rest of March, calling frequently, but vanished in early April.

1SE99. Cooper’s hawk soared above Nature Trail area of Willowbrook, moving north to south. They soar from time to time.

15JE00. Morton Arboretum. Near Parking Lot 7, when I arrived around 8am, 3 robins were giving the high‑pitched thin call repeatedly, and the forest otherwise was relatively quiet. After 10 minutes, a Cooper’s hawk started calling nearby, then flew out away from the forest edge until an eastern kingbird started to chase it. It immediately turned around and flew back the way it had come, and kept going. The robins then were quiet.

16JE00. Willowbrook. In the afternoon, a Cooper’s hawk perched near the west edge of the prairie, drawing alarm calls from a robin (the hawk‑whistle warning call) and a cardinal, and a chorus of 7 loudly mobbing jays.

18JL00. Willowbrook. In the early afternoon, a Cooper’s hawk soared low above the marsh and areas east and west of it, while 3 red‑tails soared high. One of the visiting red‑tails called once, but the Cooper’s, which has been resident all summer, called repeatedly.

26FE01. A Cooper’s called for a long time from the top of a tree near the islands in the river at McDowell Grove. A harrier was flying overhead, but the Cooper’s did not appear to be looking at it while calling.

14AP01. 2 Cooper’s, possibly a pair, at West DuPage Woods. One made an unusual flight through the open air, with exaggerated, moth-like wingbeats reminding me very much of a short-eared owl.

5MY01. A Cooper’s hawk incubating a stick nest high in a tree at Wayne Grove Forest Preserve. Tail visible from below.

10JA02. Two jays newly arrived at Willowbrook (for weeks there had been one, at most, and these were in addition to that one). They were mimicking crow caws, with lower volume and a brighter tone that made the mimicry clear, but an interesting sound. One of them also repeatedly imitated a Cooper’s hawk’s calls, both the string of notes and the isolated single notes. Again the volume was lower than in the hawk, but tonal fidelity was very good. They were in brush, low to the ground and close to me (the Cooper’s imitator was within 20 feet and clearly knew I was there). Before long I saw a Cooper’s hawk, almost certainly the same one that we saw hunting the day before by sitting and waiting on a tree branch for a minute or 2, then moving to a new perch. Today the hawk was perched about 100 yards from the jays.

12MR02. As 2 Cooper’s hawks began to call in the woods at Willowbrook, a jay flew to the treetops above them and began the bobbing “teakettle” call. Another jay arrived and began to “jay” call as the first continued on away in the direction it had been going.

26OC07. A Cooper’s hawk still calling at Fullersburg.

2006-2008. Cooper’s hawks nested at Fullersburg. The great horned owls there prefer to use a hawk nest from the previous year. In at least one year the Cooper’s were successful, as fledglings frequently were to be seen. In at least one year, and perhaps two, the hawks started to incubate but then abandoned. In one case this happened shortly after a pair of broad-winged hawks arrived and began to advertise their territory nearby.

24MR09. Mayslake. Scattered feathers of a Cooper’s hawk in the prairie south of the stream corridor marsh. The location, and nature of feather damage pointed to great horned owl as the predator.

Coopers kill 2b

 Late summer 09. Mayslake. One day a Cooper’s hawk caught a young-of-the-year robin in the woodland east of the mansion.

 Autumn 09, Mayslake. A Cooper’s hawk, flying low, could see through the windows of the library wing, and attempted to fly through as it would a space within a forest canopy. Unfortunately the windows were closed. It was not flying fast, and after bouncing off flew away, apparently unharmed.

With the winter’s slower season arriving, I expect to be sharing more dossiers. I encourage any student of natural history to be careful in separating what you know out of personal experience from what you have heard second hand.

Mayslake Birds Update

by Carl Strang

It has been a while since I have reported bird observations from Mayslake Forest Preserve. The neotropical migrants, including the eastern wood-pewee, have departed for their winter homes.

Pewee 2b

Wandering youngsters like this great blue heron have turned up from time to time.

GBH youngster Mayslake

Some members of this species will stick around through the winter, and some will make the attempt and fail to survive. One of the more unusual sightings at Mayslake this fall was a heron relative, an American bittern, which flushed from an unusual location in the middle of an upland meadow.

Mixed flocks of warblers and other songbirds stopped by the preserve for fuel in September, and gave way in October to birds that winter in the U.S. These included blackbirds, with large grackle flocks foraging on the mansion lawns on some days.

Grackle flock 2b

Sparrows frequented the habitats suitable for their various species. Meadows and prairies attracted song sparrows, some of which had nested there in the summer.

Song Sparrow 3b

One of the more unusual looking sparrows was this one.

Savannah Sparrow 4b

It proves to be a savanna sparrow, but with very white and high-contrasting plumage compared to most members of its species. Many white-throated and white-crowned sparrows have been refueling at the preserve as well.

The most exciting “maybe” was reported by an experienced birder who got a glimpse of a tiny black bird flying near the stream. He was not willing to commit to it, because his sighting was so brief, but Mayslake may have hosted a black rail this fall.

In the past week the latest of songbirds have been appearing, including a brown creeper, hermit thrushes, fox sparrows and dark-eyed juncos. Some of these may stay for the winter.

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