Closing the Book on Green-winged Cicadas

by Carl Strang

The green-winged cicada (Diceroprocta vitripennis) provides a favorite example of why I need to include 22 counties in my survey of Chicago-region singing insects. I checked a final two locations recently, and am satisfied that I have a good sense of where this species occurs.

Black dots indicate counties where green-winged cicadas can be found.

The most important habitat feature appears to be sandy soil. Cicadas spend most of their lives underground, so it is not surprising that soil texture can influence their distribution. The mapped area contains two sandy regions: the dunes edge of Lake Michigan in Indiana and Michigan, and the Kankakee River corridor. The cicadas do not, however, extend throughout those soil areas. They thin out quickly in western Starke and Pulaski Counties, Indiana, and do not reach into the sand soil portions of St. Joseph and Marshall Counties.

Green-winged cicadas had an important lesson for me this year. Previously I had thought of them as a woodland species, having observed them singing in trees, especially in black oak savannas and woodlands. Then I came to this spot in Newton County, Indiana:

A single large cottonwood and two smaller trees towered above clusters of shrubs.

I was surprised to step out of the car, expecting to focus on sand-soil grasshoppers, and hear green-winged cicadas singing. As I approached them I found that they were singing, not from the big trees, but from plants no taller than me, winged sumacs and a small black oak.

This discovery provided a welcome opportunity to photograph live green-winged cicadas.

They were very alert, and required a glacially slow stalk.

Feel free to wave back. No one is watching.

I also found a site in Jasper County where the cicadas were singing from shrubs. They can be fairly loud at close range, but they are small, with bodies not much more than an inch long, so the song quickly attenuates over distance. It seems to carry better when the singing perch is in a tree. The song is a distinctive pulsing rasp:

These early season cicadas sing mornings to mid-afternoons, and largely are done by the end of July.

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Gray Squirrel Species Dossier

by Carl Strang

For several winters, now, I have been sharing my notes on various species of our vertebrate wildlife. The main idea is to step away from the literature and other second-hand sources, and document what I know about each species from my own observations. At last I have reached the end of the list of dossiers which contain enough information to post here. There may be more in the future, as I add to the limited notes presently in unshared dossiers, but this will be the last for a while. I hope the main point has been clear: to remind you, as well as myself, to pay attention and learn from experience rather than rely on the sometimes limited or misleading second-hand reports (I shouldn’t need to point out that from your perspective, this dossier is itself a second-hand report!)

Squirrel, Gray

Gray squirrel

Gray squirrel

This species is more typical of larger forests and cities. Its relative the fox squirrel is the savanna and small woodlot species, though both can occur together (this one is not found around Culver, Indiana, however). Many notes from the fox squirrel dossier also apply to this one.

27JL77. Gray squirrels fed on unripe red oak acorns at Reineman Sanctuary, Perry County, Pennsylvania. The next day, one was eating Nyssa (black gum) seeds (discarding the fruit).

29JE86. One gray squirrel foraging on the ground in an old pine plantation at Waterfall Glen Forest Preserve, DuPage County, IL. It moved slowly (diagonal walk), nose to the ground, sometimes pushing the nose beneath the litter and walking several inches with the face thus submerged. Stopped and ate 3 small objects. Later investigation of the site revealed small oval shells with tough skins, possibly coccoons, flattened ovals viewed from side with a circular cross section, with one end neatly removed and empty inside.

20OC86. Squirrels in dense brushy old field of Willowbrook Back 40. Sounds, when alarmed, like 2-3 steps or jumps, the last louder, then quiet. Is squirrel getting to bigger shrub or a tree, jumping onto trunk then freezing and watching?

23FE87. Much renewal of nut-digging (removal) past few days (and continued next 10 days or so).

28FE87. Wayne Grove Forest Preserve. Gray squirrel stuffing itself with American elm buds in top of 8″dbh tree. Later another, also in a 5″dbh American elm. Much recent excavation of buried nuts. A third individual ate a few black cherry buds.

6MR87. Squirrel high in a black willow, cutting twigs 4-12 inches long and carrying them one at a time to the top of a major 3-branch crotch high in the tree, where it was stuffing or sewing them into a mass of them.

7AP87. A gray squirrel on the ground responded to chipmunk’s chip-trill at my approach, jumping onto low branch and looking alert.

28SE87. Lots of them on the ground in Willowbrook old field. Old and young of year, both.

23JA88. McDowell Forest Preserve. Gray squirrel dug up shallowly buried hickory nut, cutting a 1.5′-tall elm to get face in close for leverage in digging. Carried nut into tree, spent about 4-5 minutes consuming it, then ate snow off top of branch it was sitting on (about 1′ worth, a powdery, thin 0.5″ wide), went down tree and continued. Paused and looked back at me.

20MR88. A gray squirrel at Meacham Grove gathering dry leaves from ground, stuffing them into its mouth with its paws then taking them into cavity nest up in old white oak. Also gathering from among the few leaves still attached to the tree itself.

10AP88. Touched a squirrel at Hidden Lake Forest Preserve (tips of his tail hairs as he “hid” on the other side of a tree trunk barely too big for him to look around).

17AU88. A chase between squirrels, apparently not play. Gray squirrel pursuing a larger fox squirrel, which jumped out of trees twice from 15-20 feet up, landing hard, to escape (in the second jump it leaped out, seemed to sail a bit, and its fall was partly broken by a small shrub). The fox squirrel uttered a harsh call, short and sharp, like part of a mobbing call, on 2 occasions. There was an un-play-like seriousness about the pursuer.

27MY89. Young gray squirrels very curious, approach when you hold still (yesterday in the park at the Newberry Library in Chicago, today in Maple Grove Forest Preserve). They have a buzzing call, precursor of the adult’s bark.

22JE89. 2 gray squirrels eating red (not quite ripe) mulberries at Willowbrook. The berries began to ripen the previous weeks, so many other ripe ones were available.

29AU89. Many twig ends, some more than 1 foot long, cut from a sugar maple in Back Yards exhibit by Sciurus sp. The twigs were laden with developing new seeds, but only a few of these were eaten. Happened in last 24 hours (lawn mowed yesterday). No nest visible in nearby trees, and this tree 25 feet from edge of lawn, similar distance from nearest other tree.

3SE89. Gray squirrel youngster (from spring litter) passing through yard, east to west (not a neighborhood where squirrels lived).

20MR90. Gray squirrel chased fox squirrel away from Willowbrook crow cage area, then came back (note: squirrels often enter Willowbrook cages to take food from dishes. A squirrel nest has been found in the bullwinkle in that cage).

22AP90. Winfield Mounds Forest Preserve. 2 gray squirrels eating enlarged cottonwood buds high in the tree. They ascended together, the larger almost seeming to pursue, certainly to follow, the smaller. The smaller climbed in 2-foot spurts, the larger following, beginning its move as soon as the smaller’s ended. Larger flicked tail in rippling pattern reminiscent of fish or salamander courtship. The smaller may have done so once or twice, but less forcefully. Slow and deliberate, not a rapid play chase. When they were high up, it appeared the smaller would leap to another branch to escape. Larger broke off chase, and they fed. Didn’t take every bud, examined many without taking. Later, larger followed smaller to ground, then up another tree, same way. Larger sometimes sniffed where smaller had been. Larger got ahead of smaller and turned to face it, flicking tail. Smaller turned away. Etc.

1JL90. Gray squirrel in mulberry tree, feeding on ripe berries, West DuPage Woods.

26JA92. Hidden Lake Forest Preserve. Lots of nut digging by squirrels, last 24 hours. Fresh snow, overnight low 20F.

21SE97. Gray squirrel eating gilled mushroom cap, Petoskey State Park, MI. Both gray and black individuals common. One chased by red squirrel briefly.

4MR99. At mid-day a gray squirrel emerged from a hole in a large, dead willow across from the Safari Trail/Glen Crest Creek junction at Willowbrook to drive away an approaching fox squirrel. The gray immediately returned to the hole.

27OC99. Fox and gray squirrels active. Former have been eating nuts in recent days, one this morning in a box elder eating seeds, another appearing to work on a broken down old nest. Gray squirrels on ground this morning, some in woods, at least one in base of savanna finger at Willowbrook.

28OC99. Gray squirrel with nut, fox squirrel eating box elder seeds.

17NO99. A gray squirrel (young) and a fox squirrel both eating box elder seeds at Willowbrook.

2DE99. Several gray squirrels and 1 fox squirrel foraging on ground.

9FE00. Gray squirrel using an exposed (though low) leaf nest at Willowbrook.

14FE00. Many gray and fox squirrels this winter in nests only 12‑14 inches outer diameter at Willowbrook.

4MR00. A gray and 2 fox squirrels feeding on the expanding buds of an American elm near the Joy Path of Morton Arboretum. As I left the path to approach the tree to ID it, the gray squirrel immediately left and ran to other trees. As I walked up to the trunk, the lower of the fox squirrels finally left, but the higher one remained.

15MR00. Willowbrook. A gray squirrel carrying a walnut, in vicinity of trail willow den (have seen a squirrel eating a walnut near there recently).

11JE00. In a morning’s hiking south of Langlade, WI, 1 gray squirrel seen.

21OC05. Willowbrook. Gray squirrel, tail curled over its head, giving its growling-snarling-whining call with an education raptor volunteer holding a red-tailed hawk on a glove nearby. Squirrel holding still, oriented so that its right side is toward the hawk.

25JA06. Fullersburg. 2 pairs gray squirrels chasing one another, probably courtship.

10JL06. Gray squirrel eating ripening hackberries, Fullersburg’s Willow Island.

5OC10. Mayslake. A fox squirrel chased a gray squirrel on the ground in the south savanna.

Yellow-rumped Warbler Dossier

by Carl Strang

Today’s species dossier selection focuses on the yellow-rumped warbler, the species in its family that winters the farthest north, with a few sometimes staying through the winter in northern Illinois. Mainly we see them in migration, however, as they nest in the North Woods.

Warbler, Yellow-rumped

Yellow-rumped warbler

Yellow-rumped warbler

This is a very abundant warbler, observed around Culver and Lafayette in Indiana, DuPage County, Illinois, and Cumberland and Perry Counties, Pennsylvania. Usually they travel in flocks, foraging from the low understory to the canopy top. Many stay late in fall, and some appear early in spring. They retain the yellow rump patch (an obvious “follow-me” signal) year-’round. Call of fall birds “tseeet,” slight slur down in pitch early in call, then up at end, again slightly.

21AP87. Has appeared at McKee Marsh, Blackwell Forest Preserve.

26AP87. Song “tsew, tsew, tsew, tli-tli-tli-tli” (short I’s). In late morning at North Blackwell, these are sitting on perches and looking, as palm warblers did, but traveling farther between perches, working higher (mostly mid tree canopy) and not hover gleaning so much as flycatching.

29AP87. Some have songs composed entirely of the “tli” syllables, others place “tsew” syllables in the middle, others have more “tsew’s” than “tli’s.” Any combination of those two syllables seems possible, 8-15 syllables total in a song.

1MY87. Still a predominantly sit-and-wait foraging style.

4OC87. First fall migrants observed at Maple Grove.

12OC87. A yellow-rumped warbler foraged on the ground, hopping, probing, and peering under the leaves of the plants. It moved slowly, less than 1 foot per minute, turning all around.

13OC87. I observed 2 in Willowbrook’s Back 40, and on the 16th, several in the old field there.

17AP88. A couple at Blackwell Forest Preserve.

29AP88. One observed foraging in trees, spending 1-5 seconds per perch scanning, and moving 3-several feet between perches. It pursued prey once, and also tore apart a cottonwood flower. Then it sally-foraged a while. Later, it switched to reaching and probing in the flowers, moving shorter distances (mostly 1 inch-1 foot). The song was relatively weak for a warbler, accelerating through its 2-3 second duration.

7MY88. Indian Trails, Culver. One flycatching.

8OC88. Hidden Lake Forest Preserve. Abundant in woods, and in fields.

11OC88. Observed in Willowbrook Back 40.

18OC88. Observed at Hartz Lake, foraging with or at least near chickadees and golden-crowned kinglets.

17AP89. First of year seen, Willowbrook Back 40. Next mentioned 30AP, McDowell.

9MY89. One at Willowbrook, flycatching low beside stream.

21OC89. Lots of them in West DuPage Woods Forest Preserve. Foraging mainly by flycatching and hover-gleaning. Air cool, 50F or less, sunny, breezy.

Male breeding colors are much brighter, but I have yet to photograph one.

Male breeding colors are much brighter, but I have yet to photograph one.

17AP90. First of year seen, Willowbrook Back 40.

23AP90. One foraging in silver poplars at Willowbrook, probing etc. in canopies, with song: “we-see’-we-see -we-see -we-see -we-see” very fast, with slight emphasis on 2nd syllable and 20-30 seconds between songs. Afternoon.

19AP99. First of season noted at Willowbrook. Last spring migrant there 13MY.

30SE99. First yellow-rumped warblers of the fall, many at Willowbrook, 2 eating poison ivy berries. Also seen eating them on 5OC, 12OC.

20AP00. First spring migrants at Willowbrook. (I saw my first of the year 18AP while running near Warrenville).

22AP00. East Woods Trail, Morton Arboretum. Several yellow-rumps feeding high in forest canopy. One observed in crown of a sugar maple in flower. The bird was mainly sitting still, reaching into flower clusters for insects. They are singing the weak sounding song that alternates between two notes, beginning weakly, crescendo and decrescendo into a trailing, weak ending. Also calling: a harsh, “pick” sound, dull and flat in tonal quality but a sharply pronounced, sparrow-like note.

7AP01. First yellow-rumps of the season at Greene Valley Forest Preserve, feeding in trees in chickadee style, with much searching of twigs and bark, and a flush-and-pursuit seen.

30SE01. Many yellow-rumped warblers along the Fox River and on Island Park, Batavia. Spread out all over, some hover-gleaning, some flycatching, others getting poison ivy berries.

27DE01: Yellow-rumped warbler at Willowbrook, foraging at the edge of the open stream, seen to catch a small worm prey.

19DE03. A yellow-rumped warbler at Willowbrook feeding on poison ivy berries and calling, the first seen there in weeks.

28SE10. Mayslake. Some yellow-rumps eating cedar berries.

26OC10. Mayslake. In recent days I have found that yellow-rumped warblers can produce the common warbler call-note (high pitched, briefer) in addition to their lower species specific note.

10DE10. Mayslake. Yellow-rumped warbler eating cedar berries near the mansion.

Yellow-rumped warbler eating a red cedar berry

Yellow-rumped warbler eating a red cedar berry

25AP11. Mayslake. A yellow-rump singing a patterned song repeatedly, very similar to Nashville warbler song but ending just different enough to distinguish.

29AP11. Mayslake. Another distinctive yellow-rump song, this one ending like the one earlier in the week but beginning with a rising sequence of notes as in a scale.

Beaver Species Dossier

by Carl Strang

The species dossier idea came from my realization in the 1980’s that much of what I “knew” about wildlife came from the scientific and popular literature rather than personal experience. I went species by species, writing what I could remember about each one from memories of my own observations. Then I built the dossiers with added notes. The dossier begins with the initial paragraphs, followed by notes dated by a code that uses two-letter combinations to signify months.

Beaver

Beaver, Salt Creek at Fullersburg Woods

This aquatic rodent lives in ditches, rivers, and lakes. Observations to date have been in the Culver, Indiana, area (Maxinkuckee, Tippecanoe, Yellow River, Fish Hatchery), southern Ontario, and DuPage County, Illinois. The signs are seen much more often than the animals themselves; they are crepuscular/nocturnal for the most part, although the Canadian ones occasionally appeared in daytime, and I have seen them during the day in northern Lake Michigan and the West Branch of the DuPage River (mid-winter). Alarm signal: dives noisily, augmenting the splash with its flat tail.

Stand-alone lodge, Canada

They feed on bark and twigs of willow and other woody plants, storing large underwater piles of branches in fall for winter use. They also stripped bark from the 1-4″ diameter X 1-3′ long sticks used in building dams and lodges. The den can be in a bank or in a stand-alone built lodge. Bank dens are used in larger, deeper rivers and lakes, although built lodges also can be seen in such places. I have seen built lodges in Canada, Lake Maxinkuckee (Venetian Village), DuPage Co. (e.g., Churchill F.P.), Isle Royale. They have a distinctive appearance because of the white sticks, though some lodges on riverbanks are not rounded and so at first glance resemble piles of drift from the last flood. Mud also is used in construction. Lodges have been 8-15′ in diameter, 2-4′ high, usually on a bank.

Beaver dam, Tri-County State Park

Small streams may be dammed to create a pool (the most ambitious dam I’ve seen was on the West Branch of the DuPage River at Blackwell in mid-winter). Dams, like lodge coverings, are built of stripped sticks, mud, vegetation, usually have a slight U-shaped bend pointing downstream, and are not particularly high above the contained water level, though some on Isle Royale were taller than me on the downstream side. Very long dams can have a more sinuous shape; I’ve seen them more than 50′ long.

High beaver dam with trail, Canada

Beavers will carry branches from other bodies of water to the home pool. Cut trees are distinctive with large tooth marks and pointed (cone-shaped) ends. Beaver tracks are large, and have the rodent formula (4 toes front, 5 back), the webs of the hind feet not always making noticeable marks.

Beaver front footprint

31AU86. Beavers at Culver’s fish hatchery have reinforced the base of their dam with a heavy plastering of marl.

18DE86. Month-old beaver sign, Willowbrook Back 40: several black cherry trees had their bark chewed off on the stream side of the trunk. No others in the vicinity (willow, box elder) were damaged.

11JA87. At the mouth of Sawmill Creek, Waterfall Glen F.P., beavers this morning fed on bark of a box elder 7″ dbh, they had cut down earlier. They had made a trenchlike single path in 6″ snow between stream and trunk.

8MR87. 2 ash trees 8″dbh cut down but only some bark removed from trunk. Otherwise untouched, for months.

Beaver-felled tree, Fullersburg

28MR87. Beavers at Waterfall Glen cut three 8″ dbh bur oaks, ate much of the bark from 2 of them, in an area with much willow.

23JA88. McDowell F.P. Beavers built a long winding dam on Ferry Creek, 20-30 yards long

15MR90. McDowell. Beavers were active in the evening dark during my night hike program. We heard one chewing: identical to the sound of a squirrel gnawing a nut, and as rapid, but much louder. Several of us shined lights on it. It was on the opposite side of the river, standing up on its hind feet, against the tree. After at least 30 seconds of being illuminated, it abruptly ran into the river. It swam for another 20-30 seconds, still in lights, then walked up the bank back to the same tree, and resumed gnawing. The alarm splash is like a big rock being thrown in. I didn’t detect a tail slapping component.

13NO99. A beaver dam has been built across the very low West Branch of the DuPage River, Elsen’s Hill at the eastern horse ford.

29MR00. While running past the borrow pit at McDowell Grove Forest Preserve, I frightened a beaver into the water. It swam under the surface for 20 feet or so, a stream of bubbles revealing its position, then surfaced. Immediately it dove again, but as it did so I saw it deliberately lift its tail and slap it on the water. I could detect the sound of it, but the splash made by the posterior part of the body (spread feet?) was the louder sound. Perhaps the double sound makes it a communication for beavers, to distinguish it from other splashes.

11MR01. A beaver lodge is on the shore of the old gravel pit on Timber Ridge Forest Preserve (at the intersection of County Farm and Geneva Roads). There has been much recent gnawing of nearby woody plants.

8AP01. At around 8:30 a.m. at Red Oak Nature Center I heard a gnawing sound down near the edge of the Fox River. It was a beaver, sitting in the shallow water and feeding on the twigs of a shrub or small tree overhanging the river (intervening brush too thick to get an ID of the plant). The beaver was reaching up, biting off a branch, then consuming the twig. Less than about 3/16″ in diameter, the twig was consumed by the beaver holding it like a piece of stick candy and nibbling on it with gnawing sounds reminiscent of a squirrel working on a nut but more rapid. After 2-3 seconds of biting off the end, the beaver chewed with its molars for a few seconds, swallowed, then worked on the end some more. When the diameter of the remaining twig became greater, approaching 1/4″, the beaver turned it sideways (always holding it in the front feet) and quickly stripped off the bark.

22OC01. Beavers have been very busy in recent days at the marsh beside South Blackwell’s Heron Trail (marsh full of water thanks to heavy rains in recent weeks). They have trampled a path through the cattails all the way to Heron Trail, and have been cutting the small willows and cottonwoods into pieces, eating the bark from some of the bigger chunks, and hauling the tops into the water (drag marks visible in the mud).

6JL07. Fullersburg. A beaver swimming up the main channel along Sycamore Peninsula went to the shore at 8:30 a.m. and ate some root bark and twig bark from American elms. It continued upstream past the Visitor Center.

Spring Time

by Carl Strang

It’s spring, and it’s time, time to shift into the new season. There are signs in abundance.

Downy woodpeckers have been getting feisty.

On Tuesday I saw Mayslake Forest Preserve’s first butterfly of the season.

An eastern comma, one of the butterflies that hibernate in the adult form.

Yesterday I set out the amphibian traps in the stream corridor marsh. It seems doubtful there are any salamanders to catch, but other interesting things turned up last season, and I’m willing to try again.

It’s important to make sure part of the trap is out of the water, for the benefit of air breathers that may get caught.

I also have begun to break out of my routine preserve monitoring routes. I am sure that after 3 years I am getting diminishing returns from them. Yesterday provided a case in point.

I have walked the trail past this big cottonwood (40 inches in diameter) many times, but yesterday I made my way through the brush on its backside, and saw this scar.

A close look revealed an interesting story.

Years ago, beavers had the ambition of chewing down the big tree. Their gnawing girdled it half way around before they gave up, or left.

In the first of the two photos you can see how large the area is where the tree has grown back over the scar. This is the largest such overgrowth I have seen, apart from lightning scars. Those are not as deep as this, however. This is a good example of how much of this preserve’s story I still have to learn.

Great Blue Heron Dossier

by Carl Strang

It has been a while since I posted one of my species dossiers. The idea is to make a record of what I know of a species from my own experience rather than what I have learned from others. This is a valuable exercise. When I got the idea and started it, I was embarrassed by how little I could write even for common species. It has forced me to pay more attention, to observe more, to be more discriminating in what I can claim to know about natural history. Even books and, yes, Internet sources like this blog need to be read skeptically. Today I choose the great blue heron, a species that played an important role in inspiring my interest in natural history studies. Records are dated with my code that begins with the day of the month, followed by a two-letter month code (usually the first two letters of the month’s name) and a two-numeral year. The code 16JE99 would indicate June 16, 1999.

Great Blue Heron

First observed at Hawk Lake, where several fished along the east side each evening in summer during my childhood. These were an early inspiration for my bird watching interest. Also observed in PA, along the Tippecanoe River in IN, in DuPage County, in Florida. Seek food usually in relatively deep water, sit-and-wait foraging. They quickly extend the neck to seize or spear fish or other prey. On rare occasions I have seen them briefly swimming on the surface of water too deep to wade. One in FL waited for fishermen to catch fish, then ran up in hope of getting the catch.

They have loud raucous squawking calls, a brief one in flight (often when disturbed) and a longer more rattling one when handled (i.e. at Willowbrook’s wildlife hospital).

Rookery established around 1967 south of Culver, Indiana, near the Tippecanoe River, in several large sycamores at the edge of a small woodlot near S.R. 17. That site still was used through 1986. Birds appear standing in nests in mid-March, radiate out in many directions to feed. Great blue herons then also reached all parts of DuPage County, IL, despite no rookeries there (a large rookery south of the county at Plainfield).

24JA89. A great blue heron flying east of Lake Maxinkuckee, IN.

10MR00. Several herons have returned to the new, small (10-nest) colony at Danada Forest Preserve.

7MY00. Great blue herons croaking in flight, traveling above West DuPage Woods Forest Preserve. An extended string of them, so the calls may be communication between flying birds.

13NO01. I count 25 nests, now, in the Danada rookery. The trees are at the edge of a pond. They are not sycamores, but I didn’t get close enough to ID. Elm shape.

21FE02. A single heron was standing on a nest in the Danada rookery at 4p.m. The winter has been mild, and it’s not inconceivable that a GBH could have survived the winter locally.

1SE02. At 10:30 p.m., a great blue heron in Geneva, standing in shallow water in the Fox River, apparently fishing in the street lights.

16JE03. This year I know of 2 large nesting colonies in DuPage County, both established in recent years. One is at Danada Forest Preserve, the other at Pratts Wayne Woods, near the intersection of Rt. 59 and Stearns Road and visible from both.

8AU03. I kayaked between Willow Springs Road in Cook County and Route 83 in DuPage on the Des Plaines River. There is a strung-out colony of great blue herons nesting over a 2-mile stretch of river that spans the county line. The nests are in scattered dead trees close to the riverbank, taller than the surrounding trees, 2-5 nests in half a dozen trees total. Though separated sometimes by more than a hundred yards, the trees each seem to have one of the others in view.

28MR06. At Tri-County State Park, the 2 nests from last year (a new satellite of the Pratts Wayne colony) gradually had lost most of their sticks. On the 23rd, herons returned (later than in the larger colonies), and now are building the nests back up. One seen carrying a long thin stick in its beak, flying up to a perch beside the nest and giving it to its mate standing in the nest, who then added it. Two additional pairs perching in those trees, but no new nest starts yet.

18JA09. Danada. Checked great blue heron rookery. Most of the 15-20 nest trees were living cottonwoods, and 90% of the nests were in these. Two were dead trees, and three were willows. One cottonwood had 16 nests, a couple had 13, one had 11. Total nests counted 142. The rookery is in a swampy area around a large pond. Last summer I also learned of a rookery at Churchill Forest Preserve, on the islands in the East Branch of the DuPage River.

11OC10. During a dragonfly monitoring run on the Des Plaines River I noticed that, in addition to the scattered great blue heron nests in tree tops along the shore, there is at least one group of trees with a number of nests in a more concentrated colony. There are more than a dozen nests in at least 3 adjacent trees. This cluster is on the river’s south bank, east of Route 83.

Another Nest Finding Technique

by Carl Strang

Animals are teachers. This is true in a variety of ways, but today I want to share a recent lesson given me by a fox squirrel and a pair of Baltimore orioles. Earlier I described  how I found Mayslake’s north savanna oriole nest by watching the female as she carried nest material. Another pair has been active in the south savanna, but I did not know the location of their nest. On a recent day as I walked into that area I heard the voices of orioles giving sharp, repetitive notes. There were two birds, and they were in a cottonwood tree. Soon I saw a fox squirrel in the same tree.

Fox squirrel worrying orioles b

The squirrel was just sitting there, but the orioles’ agitation could only mean that their nest was nearby. I searched all the branch tips of that cottonwood, and before long found the nest.

Baltimore oriole area 11 nest b

You may have to take my word for it. The nest is in this photo, but it’s not easy to pick out. The male and female oriole continued to mob the squirrel (here’s the female in mid-note).

Baltimore oriole female b

Eventually the rodent got up and jumped to another tree. Almost immediately the orioles quieted. I watched the female as she vanished back into the nest, and I celebrated the addition of another nest-finding technique to my bag of tricks.

Flower Feeders

by Carl Strang

 

Earlier  I described squirrels and a few bird species as occasional bud feeders. Last week, as the cottonwoods began to flower at Mayslake Forest Preserve, squirrels including the fox squirrel below began to feed on these fresh sources of protein and other nutrients.

 

squirrel-eating-flowers-b

 

Earlier I had noticed squirrels sniffing around the highly swollen cottonwood buds, but did not see any feeding. Either I missed it, or they were assessing how soon their flower dinner would be served.

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