Species Dossier: Brown-headed Cowbird

by Carl Strang

Cowbirds haven’t arrived in our area yet this spring, but it won’t be too long. The following represents my limited knowledge of this, our main local nest parasite.

Cowbird, Brown-headed

Male brown-headed cowbird

This blackbird has been common essentially everywhere in the eastern U.S. I’ve gone. They feed in and around open areas and fields. Females lay eggs in other birds’ nests, early examples observed in warbler nests of a few species. They sometimes stayed around Culver, Indiana, in winter, taking seeds from feeders.

31MR99. First of season noted at Willowbrook.

29MR00. Willowbrook. Cowbird males displaying in high, bare tree tops: a group of 5, and a group of 3 (one of the latter had left the first group). No females were present with the group, but a female was present elsewhere on the preserve. The display consisted of fanning the wings out to the side, fanning the tail and lifting it above back level, then bowing or leaning forward to the point of sometimes losing balance. While performing the display, the bird at least sometimes gave its high‑pitched call. (I call this the falling-down-drunk display.)

Falling-down-drunk display, closely watched by a female.

1JL00. A female yellow warbler fed a cowbird fledgling near the south end of Silver Lake at Blackwell. Earlier this week a pair of scarlet tanagers fed a cowbird at Willowbrook, and half a dozen times this spring I have seen male cardinals feeding them (some were the same pair, but at least 3 different broods were involved), also at Willowbrook.

12OC02. After not seeing many in recent weeks, a couple individual cowbirds appeared earlier in the week at Willowbrook, and today, a number of them, especially young ones, were at Fermilab.

19JE08. A pair of gnatcatchers fed a cowbird fledgling at Fullersburg.

20JE09. Last year I also saw song sparrows feeding a cowbird at Fullersburg. This year at Mayslake I have seen cowbirds fledged by phoebes and Baltimore orioles.

Fledgling cowbird being fed by a female Baltimore oriole.

15JL09. Mayslake. Yesterday in the south savanna a cowbird fledgling was being attended by a song sparrow. Today another fledgling was in the north savanna being fed by a phoebe, clearly a different brood or pair than the earlier one (last observed 3 July).

Common Grackle Dossier

by Carl Strang

In anticipation of spring, this week’s choice of species dossier features a bird that winters not so far to our south, and so is one of the first to arrive in spring.

Grackle, Common

Courting group of grackles in a quiet moment.

Typically this is a colonial nester in tall trees, although I have seen low nests (e.g., at Purdue gravel pit). Birds radiate out from the colony to feed, traveling at least up to ½ mile. They feed mostly on the ground, in tall (at least 6″) grass in summer in Pennsylvania, in forests in early to mid-spring in Illinois. Latter birds feed in groups, noisily throwing leaves aside with beaks as they walked. Former ones fed more commonly as individuals.

Squeaky, rusty-hinge voice. In early May 1986, at West DuPage Woods Forest Preserve, Illinois: A large male grackle, perched on a bare branch beside the river, periodically gave his squeaky “erlik-geck” call. Each call was accompanied by elevation of the feathers of the head, neck and upper back and chest. Feather elevation began slightly before vocalization. Alarm call is a series of rapid “geck” notes.

Migrates south for winter, forming large flocks mixed with other blackbirds (especially red-winged) in fall, disappearing in November from northern Illinois and Indiana, reappearing in March. The male holds his long, wedge-shaped tail vertically in long straight flight. That tail also can be held in a V-shape.

Migrant grackle flock, foraging on Mayslake mansion lawn.

Both parents participate in feeding. Nestling grackles at Willowbrook’s hospital were unusual in their lack of aggressiveness in taking food. They would not bite food off its holder (implying regurgitation by parents into the nestling’s throat?). The inside of the mouth is dark red on older youngsters.

7MR87. First arrival of year noted at McKee Marsh, Blackwell Forest Preserve.

7MY87. Grackle caught moth it flushed from lawn, removed wings before eating.

4JE87. Broods out of nest, not strong fliers, still begging hard.

11JE87. Mother grackle fed youngster several items, apparently brought up from her crop although some she picked up nearby on the ground. After she flew off, the fledgling pecked at the ground, picking up dropped bits, and also did some close looking of its own into the grass.

14SE87. Migrants in Willowbrook Back 40, also one on 28th.

6MR88. Numbers of grackles are back.

2AP88. Grackles flying in pairs and showing much courtship activity in past week.

8AP89. Grackles mostly in pairs.

17JE89. A broad-winged hawk calling repeatedly, in north end of Maple Grove. Jays, flickers and grackles highly agitated, flickers the most continuously vocal with “keels” every 2 seconds (2 birds). Grackles gacking frequently, too.

18JE89. Grackles foraging in forest litter, Maple Grove and Meacham Grove Forest Preserves.

Grackles perched near a nesting colony.

30JE96. As I paddled my sea kayak on Lake Michigan, just north of the IL-WI border, I saw many grackles along that 2-mile stretch foraging over the surface of the water. Both genders. The birds flew pretty much straight out from shore, 100-200 yards, and then flew back and forth until they saw something on the water to pick up. Then the bird dropped down and reached for the item with its bill. There were lots of dead and dying small fish, and on at least 2 occasions these clearly were what the grackles picked up. At other times the objects appeared to be too small or the wrong shape. Sometimes a grackle dropped down and appeared to miss, or not even quite reach the surface, but it seemed that after a single try, successful or not, the bird headed straight back to shore (sometimes dropping down to the water on the return trip, though). They flew along as high as 30 feet, usually 10-15, and when seeing objects they spun on a wing and often hovered, looking surprisingly tern-like. They minimized contact with the water, though one that dropped down close to me, where I could see clearly, plunged its head into the water, and its tail tip dipped in as well. Their fluttering flight appeared clumsy and energy-gobbling when compared to the purple martins, gulls and terns also cruising those waters.

22FE99. First of year noted at Willowbrook.

12AU99. 2 grackles hunting up in trees.

2NO99. Last of season at Willowbrook.

31OC01. Flocks of red-wings and grackles remain (Nelson Marsh, Kane Co.)

4NO01. An enormous flock of red-wings and grackles along Kirk Road in eastern Kane County. The species were staying apart, on the whole, and there were mainly grackles, but there were hundreds of each. They were landing in a harvested corn field.

18MR09. Both red-wing and grackle include tail fanning and wing spreading in their displays. In the red-wing, these movements accompany the song but are expressed in a range from not at all or nearly so, to slight fanning of tail, slight tail fanning and spreading of wings, and finally much tail fanning and wing spreading.

Grackle courtship flock, displaying

1JE09. Mayslake. First grackle fledglings.

18MR11. Mayslake. Most grackles still are males, but a female often is among them from the start (when a pair forms do they leave, so males always outnumber females?).

29MR11. Mayslake. Displaying grackle group. Often there is only one female with the several males. In the past week or two I frequently have noted trios of flying grackles, one female with 2 males.

Mallard Species Dossier

by Carl Strang

Today I share my dossier on one of our most familiar birds, the mallard duck. This is one case in which my initial entry in the 1980’s was large enough that it remains the bulk of the file.


Adult male mallard

Widespread, common marsh bird, also frequenting suburban ponds, lakes and streams. Singles and pairs occasionally appeared in western Alaska, but the mallard was not a common species there.

Adult female mallard and ducklings

Courtship begins in September in Illinois and Pennsylvania, as drakes come out of eclipse, but (at least in northeast Illinois) may not peak until January. The male has a large variety of courtship displays, generally preceded by preliminary shakings of the head from side to side, tail shaking, and lifting and shaking the entire front half of the body (the last seems to represent a higher intensity). The most common of the male’s displays is the Grunt Whistle, beginning with lifting the front half of the body (note similarity to the most intense form of the Preliminary Shake). While the body is lifted the neck is arched forward and down, and the tip of the bill is used to flick out an arch of water drops. As this happens the bird emits a high-pitched peeping sound. Frequently several males Grunt Whistle together, and in fact courtship displays generally occur when several males plus at least one female are close together on the water.

Mallard Preliminary Shake

Down-Up is another display, in which the male lowers the front of his body into the water while lifting the tail end. The bill points down as the bird dips, then it is pointed upward. This is an especially beautiful display when several males, facing one another, bow simultaneously.

In Head-Up-Tail-Up, the body is contracted while the neck stretches upward (bill kept level). This always ends with a bout of Nod-Swimming, with the bird swimming rapidly low in the water, neck stretched low and forward, pumping slightly as the bird swims.

Sometimes several courtship displays may be performed simultaneously. Here, the two males on the left are performing the Down-Up display, the one on the far right is performing a Grunt-Whistle, and the one just left of him appears to be in a Head-Up-Tail-Up.

Males and females can be seen together more and more in pairs as winter and spring pass. The female continues to test the drake with Inciting, a display in which she mechanically waves her bill back and forth to point toward another nearby mallard. The male commonly responds by chasing that bird away. Rarely and inexplicably, drakes perform the Inciting motion.

Female mallard performing the Inciting display.

Copulation begins usually with the male performing an exaggerated vertical pumping of his neck with the bill held parallel to the water surface. If the female is receptive, she identically pumps her head. After the two have done this together a few seconds, the male swims behind her, then climbs onto her back. Head pumpings cease as the male achieves a grip on the back of the hen’s upper neck with his bill. She sinks low in the water, he swings his tail around to the side of hers as she pulls hers out of the way, and genital contact is made. Post-copulatory displays are bathing motions by the female and Nod-Swimming by the drake.

The presence of a male with the brood may be a sign that these birds have some domestic mallard in their ancestry.

Pairs appear on land in mid-spring, usually with the female leading the search for a nest site. The nest is built of grasses mixed with down. Generally one pale blue-green egg is laid per day until the 8-13 egg clutch is complete, then the female incubates the eggs and usually raises the young alone. After the ducklings hatch and dry, they follow the hen on an early-morning trek to water, sometimes a mile or more distant. On 8JE86 I saw a drake with a female and large downy ducklings on land, an exception to the rule that males stay away from broods which females raise alone. This was in DuPage County, where ducks are unusually dense because of artificial feeding, and there is considerable domestic mallard in the gene pool. Single failed-nest females sometimes become injured from rape attacks by multiple males. Possibly this male was insuring against the loss of the brood. Young ducklings are distinguished from those of wood ducks by a dark line between the eye and bill, and a darker yellow base color.

Female incubating a nest

General vocalizations include peeps of ducklings, loud call of adult females (series of quacks, first one long and successive ones shorter), and a chuckling continuous call occasionally performed by flocked birds on the water. Mallards winter in DuPage County. Occasional large flocks spent the early winter in the center of Lake Maxinkuckee in Indiana, flying out to harvested corn fields to feed. Mallards feed on the surface of water or tip up to take food from the bottom.

Occasionally an incubating duck leaves the nest for a time. When she does so, she covers it with the mixture of down and grass for camouflage.

Once a hen had a nest in my fenced-in yard in Warrenville, but abandoned before incubation was complete.

Mallard eggs are a pale green in color.

19AP99. Mallard nest at Willowbrook under a columbine, against east wall of garage/bird nursery building (was gone, abandoned or destroyed, by 30AP).

14MY99. Mallard female with 7 young ducklings in stream at Willowbrook.

17SE99. Some mallards at Willowbrook appear to be in eclipse plumage, or perhaps young are molting into their first adult plumage.

29OC00. McKee Marsh. A green-headed male with a group of black ducks has a very dark gray body, no curly tail feathers, and no white neck band, apparently a hybrid.

4MY09. Mallard male with female and duckling chased away another male that showed interest in the female.

Mallard ducklings approaching maturity

23NO09. Mayslake. A dozen mallards were diving for food in May’s Lake, coming up with aquatic vegetation after being completely under water 3-5 seconds. A pied-billed grebe was with them, also diving.

Cedar Waxwing Dossier

by Carl Strang

One delightful bird which can be seen in northeast Illinois throughout the year is the cedar waxwing. Today I share my dossier for the species, consisting entirely of my own observations. Though references are valuable it also is important, I think, to keep track of one’s own experiences with a species.

Cedar waxwings are smaller than robins but larger than sparrows, crested, soft brown and yellow in color with bright yellow follow-me bands on the tail tips.

Waxwing, Cedar

My principal childhood memory is of waxwings that nested around brushy thickets and willow clumps along the Tippecanoe River near Monterey, IN. Adults hunted insects in flycatcher fashion from bare twigs over the river. In DuPage County they are evident in wandering flocks through all parts of the year except the breeding season. They travel in flocks, staying one to many days in an area and feeding on berries in fall and winter. This also occurred in Cumberland County, PA. Mountain-ash berries were a favorite food in both places. Also consumed are dogwood, and buckthorn berries. Flock cohesion is aided by the bright-yellow tips of the tail feathers, and by the unique high-pitched thin contact call. First winter birds have breasts striped longitudinally with cream and the soft brown adults’ breast color. At the Willowbrook Wildlife Center clinic, waxwings frequently came in with broken wings and other injuries suffered in collisions with windows. In the cages they showed an open-mouthed threat display, possibly made more effective by the black facial markings. In mid-September at Herrick Lake, a single waxwing perched in an old-field treetop gave a single loud note and flew away into thicker trees. Several seconds later a sharp-shinned hawk flew by the waxwing’s original perch, heading in the same direction. (This first paragraph, written from memory, established the dossier in the early 1980’s. Subsequent additions begin with date codes.)

When not feeding, cedar waxwings typically perch high in trees.

30OC86. Willowbrook Back 40. Waxwings feeding heavily from honeysuckle (berries and leaves still on bushes).

16OC87. First autumn appearance of a flock at Willowbrook Back 40.

13JA88. Lots of waxwings in Back 40.

27OC88. Feeding on honeysuckle berries, Willowbrook Back 40.

13DE88. Waxwings abundant in Back 40, stuffing down rose hips.

3SE89. Mixed young and old waxwings eating honeysuckle berries, Island Park, Geneva.

JA99. Waxwing flocks frequently at Willowbrook. Eating, among other things, Asiatic bittersweet (Celastrus) berries.

11MR99. Last of winter waxwings noted. Not seen again at Willowbrook until 25MY. Then after 1JE another gap until 12&20JL. Became a frequent visitor again in early August.

These waxwings are drinking meltwater where snow is being warmed on a roof at Mayslake Forest Preserve. Much energy is saved by drinking, even if the water is cold, instead of eating snow.

7JA00. Waxwing eating buckthorn berries.

31JA00. Waxwing, again at Willowbrook, again eating buckthorn berries.

8FE00. Waxwings eating buckthorn berries at Willowbrook.

17FE00. Several waxwings on the ground eating snow (buckthorn berries available on bushes nearby).

19MY01. Many flocking waxwings spread out over a large area at the Arboretum, mainly in treetops in forest as well as more open areas.

12MR06. Cedar waxwings delicately picking anthers from silver maple flowers in the yard. [Note: studies have shown that waxwings use protein from pollen to render certain berries more digestible]

13JE06. Tri-County State Park. Cedar waxwing working on a nest in the topmost leaf cluster in a 25-30-foot box elder within 30 yards of Brewster Creek. Weaving, using long slender strands, at least some of which are stripped from grape vines. Spending considerable time with each strand. Mate perched in same cluster of trees. Bird completely concealed when weaving.

This is the tree where waxwings built a nest at (then) Tri-County State Park in 2006.

16JE06. The nest looks complete, a significant lump in the first branching of twigs about a foot from the tip.

22MY08. Fullersburg. An interesting display between 2 cedar waxwings, appears highly stereotyped. They were perched side by side well up in a tree in SW Butler Woods. They took turns quickly hopping away from the other bird a few inches, and returning, at which point the two birds touched or nearly touched beaks, which were angled up. Each of these cycles (or half-cycles, for each bird) took 1-2 seconds, and there were perhaps 20 reps that I observed (i.e. at least 10 per bird). At first they faced the same way, at some point one turned to face the other way and they continued. Eventually one moved to a different twig, but still was close. [Note: this is called the Side-hop display in the Stokes bird behavior guide, and is part of courtship].

6JL09 Mayslake. 14 cedar waxwings foraging like swallows out over May’s Lake. (This was repeated over several days.)

1JA10. Hidden Lake. Waxwings and robins feeding on buckthorn berries.

Blackbird Activities

by Carl Strang

Though spring is well underway now, it was slow to get going. The first red-winged blackbird males appeared at Mayslake Forest Preserve weeks later than last year. Here one forages in a brushy woodland, showing how he can conceal his brightly colored wing patches when not displaying.

He checks something of interest overhead.

Female red-wings show up weeks after the arrival of the first males.

Red-winged blackbirds have a typical songbird pattern of males defending nesting territories and attracting females, who judge the strengths of the males and their territories in deciding where to raise their young. A different mating system is used by another blackbird, the brown-headed cowbird. Here (according to the literature) the territories are defended by groups of males, who have a social dominance hierarchy in which the top male gets most of the matings with females the group attracts. Certainly my own observations support this understanding. Here are three cowbirds, a female and two males.

Male cowbirds display with a high-pitched squealing vocalization that has been shown to be amazingly complex when slowed down and analyzed. What is easier for us to discern in real time is the accompanying visual display, which I call the falling-down-drunk display.

The male loosens his grip on his perch and falls forward, contorting his body as he flops open his wings and fans his tail. Perhaps what is most impressive is his ability to recover his upright position afterwards. If he succeeds in attracting the female, they will go on to mate and she will begin to seek foster nests in which to deposit their eggs. Cowbirds are obligate nest parasites.

Species Dossier: American Kestrel

by Carl Strang

This week’s species dossier focuses on a species which seems to have become less common locally than it once was. Certainly I don’t see them as often as I did along the same roads in years past.

American Kestrel

Typically I have seen this small falcon along the road or at a field with few or no shrubs. They catch voles by diving from the air and pinning with their feet. They sometimes hunt from a perch, sometimes from the air, and often can be seen hovering over an open field before diving to the ground. They can be seen year round in DuPage County IL, Marshall County IN or Cumberland County PA, though they leave if the weather becomes severe in winter. The male’s courtship display consists of high altitude flight and steep dives accompanied by a “killee killee killee killee” call slightly reminiscent of a killdeer’s. Male has red tail, black round spots on breast, bright-colored head. Larger female has brown and black barred tail, no breast spots, duller head colors.

10JA80. Boiling Springs, PA.In the afternoon I watched a crow chasing a kestrel. The birds flew high, and the crow stayed right with the little falcon’s twists, turns and dives. Finally, the crow broke off after the chase had carried the two a couple of hundred meters from the starting point. The crow flew back there, and the kestrel flew a parallel course 50m away, but continued out of my field of view.

16NO86. Herrick Lake Forest Preserve, IL. Late afternoon. Female kestrel carrying small brown mammal in talons (prey looked all brown, but maybe had long tail). In sparse fencerow beside tall grass field.

(Date not recorded). DuPage County, IL. At the edge of a construction site a kestrel perched, its attention focused on a small isolated patch of tall grass.

18AU89. Willowbrook Forest Preserve marsh. Blue jays were mobbing a kestrel, making strange, harsh, parrot-like calls and sometimes chasing the falcon. The kestrel stooped at the jays a couple times, but the jays kept mobbing until the kestrel left.

17OC92. Vicinity of Cantigny (Winfield, IL). While driving I saw a kestrel carrying a house sparrow low across the road. It was a heavy load for the kestrel, which lost its grip, perhaps distracted by my car’s close proximity. The sparrow flew away. Many times I’ve seen kestrels searching vole habitat, carrying or eating mice. This, I believe, is the first bird capture I’ve witnessed.

8MR00. Willowbrook. In the afternoon, a kestrel calling above the Wildlife Center buildings and outdoor exhibits, perched briefly.

22AU04. Canadian side of Lake Superior. I passed through an area where there had been a big fire, and saw there both the first kestrel and the first red-tail of the trip, showing them to be associated with relatively early successional, extensive areas in this part of the northern forest.

Bufflehead Dossier

by Carl Strang

My species dossiers, containing what I know of a given species from my own observations, vary greatly in length. The bufflehead is a duck I have seen only on migration, mainly on Lake Maxinkuckee at my home town of Culver in north central Indiana.


Common migrant on Lake Maxinkuckee. Also seen at McKee Marsh in DuPage Co. IL. Generally forms small flocks of 2-10 that don’t mix with other waterfowl species. Dive for food (usually under ~15 sec. at Maxinkuckee). Stay 50-500 ft. out from shore there for the most part.

21MR65. Bufflehead 3 males 3 females. 2 males and one female going through vigorous courtship displays: all pump heads up and down vigorously, males scoot through water on tails, dive under water for a couple seconds, all fly into the wind for a few feet, etc. Once in a while they all fly around the area swiftly. Males have orange-red feet, females brown.

1&7MR87. Some buffleheads at McKee Marsh, Blackwell Forest Preserve.

10AP93. Buffleheads in groups on Maxinkuckee (observed from kayak) engaged in male displays and Inciting. Female Incited the chosen male repeatedly to chase other surrounding males who were displaying by taking flight past the female, at first as though flying away, then fanning the bright orange feet out to the sides, dropping into the water with chest raised high, then dropping the chest in a bow, doing a quick Head-up-tail-up, bathing stereotypically for a second or two, then several quick pumpings of the neck straight up and down.

4AP99. First of year seen, Culver.

(Looking at these accounts, I am struck by how my 1965 description at age 14 had some merit but lacked the better quality of my more mature 1993 account. The odd terms in that paragraph refer to certain named displays buffleheads share with mallards. I described Inciting in an earlier post, Stupid Duck Tricks).

Singles Bar

by Carl Strang


The blackbird family is an interesting study in mating systems. The red-winged blackbird  has the typical songbird pattern of separate nesting territories established by the males, who then attract one or more mates (depending on the quality of the male and of his territory), each of whom produces a clutch of eggs.


The common grackle has what I call the Singles Bar mating system. I have observed this casually in past years. This year I decided to focus a little more closely. The first grackles arriving from the south all appeared to be males. Very quickly their numbers rose enough that they began to gather in treetops and display.




Compare the above photo to the one below.




In the first photo, the birds are focused mainly on me. In the second, the one in the middle is displaying, fanning his wings while he calls. Notice how the others all are turning to watch him. The wires above the red cedars along the east boundary of Mayslake Forest Preserve provided another display area. I will be interested in seeing if those cedars become the location of a nesting colony later in the season.




Grackles are not as fiercely territorial as their red-winged blackbird relatives. Often they nest in colonies. These display groups draw in females, and the females select their mates. I had hoped to observe this in action, but apparently it has progressed more rapidly than I expected, for already these singles bars appear to have evaporated and I am seeing pairs of grackles flying around together. Next year I’ll hope to try again. I had expected a more prolonged sorting out, with many females present at once. Instead I now suspect that the females joined the males singly rather than in groups, and fairly quickly settled on their mates. Later I plan to feature a third blackbird mating system, that of the cowbird.

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