St. James Farm is Singing

by Carl Strang

Birds poured into St. James Farm Forest Preserve in mid-May as the wave crest of neotropical migrants pushed through northern Illinois. On some days, sorting through the many songs to note visiting species was a challenge.

Not all were singing, though, for example this bald eagle that stopped in the restored stream corridor.

Not all were singing, though, for example this bald eagle that stopped in the restored stream corridor.

Blue-gray gnatcatchers are common on the preserve, and are among the earliest nesters.

Blue-gray gnatcatchers are common on the preserve, and are among the earliest nesters.

I am hoping this hooded warbler, singing among the thicketed portions of the central forest, will find a mate and nest there.

I am hoping this hooded warbler, singing among the thicketed portions of the central forest, will find a mate and nest there.

I took that photo from a distance on a foggy day, not wanting to get too close and create a disturbance.

This sharp-shinned hawk was very vocal, its calls to my ear less like those of its relative the Cooper’s hawk and more like those of a shorebird.

This sharp-shinned hawk was very vocal, its calls to my ear less like those of its relative the Cooper’s hawk and more like those of a shorebird.

At one point, heavy rains flooded the stream well beyond its banks.

The engineered restoration corridor held up well to the challenge.

The engineered restoration corridor held up well to the challenge.

Among the water-loving birds that took advantage of this temporary habitat expansion was a double-crested cormorant, here taking a break between swims.

Among the water-loving birds that took advantage of this temporary habitat expansion was a double-crested cormorant, here taking a break between swims.

After the water receded, the deposited mud interested a few late shorebird migrants, including this least sandpiper.

After the water receded, the deposited mud interested a few late shorebird migrants, including this least sandpiper.

For other birds, the breeding season is well under way.

I am not sure where this goose brood came from, but they have found the restored stream corridor to their liking.

I am not sure where this goose brood came from, but they have found the restored stream corridor to their liking.

Among my happiest observations in the second half of May has been the discovery of two eastern bluebird nests in natural cavities.

Here the male stuffs food into unseen nestlings in a bur oak cavity.

Here the male stuffs food into unseen nestlings in a bur oak cavity.

Mom takes her turn. In just a few minutes I saw each parent make 3 such feeding trips.

Mom takes her turn. In just a few minutes I saw each parent make 3 such feeding trips.

The same story was repeated in a dead tree near the stream. I am relieved that not all bluebirds are dependent upon human-provided nest boxes.

A little earlier in their own cycle, a pair of red-headed woodpeckers has been setting up shop in another dead tree.

They have settled upon the lower of the two holes beside the foreground bird.

They have settled upon the lower of the two holes beside the foreground bird. (Clicking on any photo will blow it up for better viewing).

This pair energetically repelled another pair which expressed interest in their tree. I hope the other pair also will nest at St. James Farm.

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).

Mayslake Miscellany

by Carl Strang

A highlight at Mayslake Forest Preserve this year was a successful red-tailed hawk nest. The single fledgling stuck around the mansion grounds and prairie area for several weeks, frequently making its presence known with high-pitched calls (“feed me!”) or perch choice on favored high points.

The bird has been absent from that area in recent days. We wish it well.

One day in mid-August there was much activity by black-capped chickadees and blue-gray gnatcatchers among the goldenrods and Queen Anne’s lace.

Their small size and acrobatic ability allows them to exploit a temporary abundance of insects in such places. I suspect the gnatcatchers were migrants. Already the season is turning.

The red-colored saddlebags dragonflies have vanished, after being a daily presence for the early part of the season.

Like this male, I suspect that all or most were Carolina saddlebags. I wasn’t the only observer in northeast Illinois seeing more of these than usual. That’s the way it is with insects. A species has an outbreak year, for reasons we often don’t understand, then usually drops back to its typical low level the following year.

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).

Mayslake Bird Notes

by Carl Strang

We are well into the nesting season for nearly all species of birds in northeastern Illinois. The white-breasted nuthatches in the savanna have fledged their young.

Nuthatch fledge 1b

There were four fledglings. They moved about 50 yards from the nest and stayed in a small area for a few days, then drifted west out of the savanna. Nearby, blue-gray gnatcatchers scrambled to keep up with the demands of their more scattered youngsters.

Gnatcatcher b

The red-bellied woodpeckers (one pair on the preserve) have their young near to fledging. Here an older nestling peers out,

Rb woodpecker nestling 1b

and soon is gratified by Mom’s arrival.

RB woodpecker mom at nest b

Meanwhile, a male bluebird has been favoring a song perch atop the chapel.

Bluebird cross b

(That’s the tip of a lightning rod behind his head). Several bluebird houses are near, but some are occupied by tree swallows. I have seen fledgling swallows recently, which means there are vacancies. A final bird topic pertains to chimney swifts.

Chimney swift 1b

A review of the literature on the species indicated that a given chimney will have only one nest in it. The Mayslake mansion provides for a possible inquiry on this subject. Some active chimneys have been capped, and so are unavailable.

Chimney 2b

Other chimneys are not capped. I once saw a swift drop into one of the chimneys in this pair.

Chimney 3b

Here is yet another tall chimney.

Chimney 4b

Especially intriguing are the fake chimneys.

Chimney 1b

This set of 8 stacks is entirely decorative, but I have twice seen swifts drop into one of the holes in the southwest quarter. This is where the potential for inquiry comes in. Given that a single hole will have only one swift nest, do the extra holes in clustered chimneys, fake or real, provide additional nesting habitat or will one pair claim the entire cluster? I have not seen swifts entering chimneys often at Mayslake, but I will continue to collect observations in hopes of addressing this question.

Cowbird Fledglings

by Carl Strang

Over the past 2-3 weeks I have been noticing cowbird fledglings at Mayslake Forest Preserve. These are the offspring of obligate nest parasites: brown-headed cowbirds cannot nest themselves, but rather lay their eggs in the nests of other birds. Foster parents that fail to recognize the foreign egg will raise the baby cowbird, often at the expense of their own young. The cowbird develops rapidly, and begs vigorously, gaining an advantage. Here is a fledgling cowbird raised by Mayslake’s eastern phoebes earlier this year.

Cowbird fledgling 2b

I saw no phoebe fledglings. The cowbird’s begging call is distinctive. It sounds like a chorus of baby birds, and probably qualifies as a supernormal releaser. That term refers to an exaggerated stimulus that produces a particular instinctive response by an animal. In this case, the call draws disproportionate attention, in the form of food, from the foster parents. If you hear a chorus of baby birds that all start at once and all pause for breath at once, you probably are hearing a single cowbird youngster.

I heard this call coming from the cottonwood tree bearing the south savanna Baltimore oriole nest . As I like to do, I found the cowbird and waited to see what would come to feed it. The foster parents were the orioles. Here the female feeds the cowbird.

Baltimore oriole feeds cowbird b

I watched for a few minutes, during which the female fed the cowbird three times, the male oriole fed the cowbird once, and he fed the baby orioles (still in the nest) once. A period of rain and work duties kept me from checking for a couple days, by which time there was no sign of any of these birds near the nest.

Over the years I have seen cowbird fledglings being fed by yellow warblers, song sparrows, scarlet tanagers, blue-gray gnatcatchers and cardinals. Cardinals are common at Willowbrook Forest Preserve, but for several years the only time I saw cardinal fledglings was late in the season, after the cowbirds were done. All early products of cardinal nests were cowbirds. This kind of selective pressure is what has led many birds to evolve the capacity to recognize and reject cowbird eggs. Obviously such an ability remains to emerge in many others. Incidentally, once the cowbird becomes independent, it instinctively seeks out other young cowbirds and behaves as a cowbird from then on.

Bird News

by Carl Strang

 

In my last update of bird arrivals at Mayslake I didn’t have photos of a couple of the species I mentioned. Here is the loon, which stayed for 4 days but left when the weather got nice and the May’s Lake shores became sprinkled with fishermen.

 

loon-mays-lake

 

Here the loon takes a peek to see if there are any particular fish to chase.

 

loon-looking-b

 

I also mentioned the season’s first barn swallow. The next day there were three.

 

barn-swallows-b

 

Lately the most abundant migrants have been yellow-rumped warblers.

 

yellow-rump-1b

 

A new warbler on the scene on April 23 was this palm warbler.

 

palm-warbler-b

 

That same day, the lakes enticed an osprey to stop.

 

osprey-mayslake-cropped-b

 

Later, the osprey caught a bullhead.

 

New arrivals I haven’t gotten a chance to photograph are field sparrow, swamp sparrow, chipping sparrow, Swainson’s thrush, blue-gray gnatcatcher, and eastern kingbird. For now, the rush of migration and seeing familiar birds for the first time in this new place is enough for me. These records provide a foundation from which potential future inquiries may grow.

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