Birds in Transition

by Carl Strang

Soon the first wave of birds that overwintered in the tropics will reach northern Illinois. April has brought a transition from wintry weather to the warmth, plant growth and insects that make the trip worthwhile for the many species whose ancestors were content with tropical conditions.

For most of the month we see birds that are year-round residents or are newly arrived from their wintering grounds in the southern states. They have to deal with the season’s variability, though. Early in April a cold spell brought a thin snowfall. There still were insects to be found, but they were on or close to the ground. A selection of species foraged on the banks of the stream at St. James Farm Forest Preserve.

These included an eastern bluebird that abandoned his practice of hunting from tree branches, and shifted to hopping around in the open.

These included an eastern bluebird that abandoned his practice of hunting from tree branches, and shifted to hopping around in the open.

The preserve’s first yellow-rumped warbler of the year also searched for prey there, though such bank foraging is a common practice for that versatile species.

The preserve’s first yellow-rumped warbler of the year also searched for prey there, though such bank foraging is a common practice for that versatile species.

Even an eastern phoebe was forced to a ground-foraging interval.

Even an eastern phoebe was forced to a ground-foraging interval.

On other days, getting set for the nesting season was a priority.

Cooper’s hawks occasionally called in wooded areas, considering whether to nest at St. James Farm.

Cooper’s hawks occasionally called in wooded areas, considering whether to nest at St. James Farm.

Song sparrows sang as they began to sort out their territories.

Song sparrows sang as they began to sort out their territories.

Cardinals have been singing since January, as they are the songbirds most sensitive to day length change.

Cardinals have been singing since January, as they are the songbirds most sensitive to day length change.

Pairs of hooded mergansers hung out on ponds where there are wood duck boxes.

Pairs of hooded mergansers hung out on ponds where there are nest boxes.

The preserve’s red-tailed hawks completed their nest and were good to go.

The preserve’s red-tailed hawks completed their nest and were good to go.

A second pair of geese chose St. James Farm for nesting, but their site is a risky ridge beside the stream, with water on each side but reachable from either end by a coyote.

A second pair of geese chose St. James Farm for nesting, but their site is a risky ridge beside the stream, with water on each side but reachable from either end by a coyote.

April 21 was warm enough that the great horned owl young did not need brooding. This was my first look, and I could not be certain there was more than one.

April 21 was warm enough that the great horned owl young did not need brooding. This was my first look, and I could not be certain there was more than one baby.

And now, with the warm days forecast ahead, the big push of migrants soon will diversify the preserve’s avian picture.

 

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Mayslake Burns

by Carl Strang

Smoke rose in thick columns on Thursday as the Forest Preserve District’s controlled burn program reached Mayslake Forest Preserve. Mayslake has well-established restored prairies, and the burn cleared off the dead tops of last year’s growth. The fire released minerals back to the soil, opened the way for the living roots to send new, unimpeded shoots skyward, blackened the soil further to facilitate plant growth by soaking in solar heat, and knocked back undesirable, competing woody plants.

A prairie burn is an impressive thing to watch.

A prairie burn is an impressive thing to watch.

Goldilocks would appreciate the decision to burn on a given day. Everything has to be just right. There needs to be some wind, but not too much. The area has to be large enough but not too large, and bounded by mowed areas or other fire stoppers. The vegetation needs to be dry enough. Finally, the burn crews need to be sufficiently equipped and trained to manage the burn safely.

Ranger staff keep watch from all sides.

Ranger staff keep watch from all sides.

Sometimes burns are incomplete due to the plants being too wet, but this time the prairies burned well. A walk through a recently burned area is worth taking, as it reveals what was hidden by all that herbage: the microtopography of the land, which can help determine exactly which plants grow where; the networks of animal trails, large and small; skeletons of animals that lived their last moments there. No freshly killed animals, though. They have their ways of escaping the flames.

Tiny low spots can host a few plants that prefer slightly wetter soils.

Tiny low spots can host a few plants that prefer slightly wetter soils.

The day after the Mayslake burn I found a number of animals taking advantage of the change. Killdeers and robins ran unimpeded over the cleared ground. Migrating sandhill cranes took advantage of thermals rising from the blackened soil to gain altitude during their journey north. In a few days, the warming soil will release and activate insects, and eastern phoebes likely will congregate to feed on them.

A robin hunts on the newly opened ground.

A robin hunts on the newly opened ground.

Sandhill cranes on the thermal elevator above the burn site.

Sandhill cranes on the thermal elevator above the burn site.

Another month, and the ground will be thick with new green shoots. The prairie always grows better in a burn year. (Note: This post first appeared last week as a Nature Note in the Forest Preserve District of DuPage County’s Observe Your Preserve website. )

Eastern Phoebe Species Dossier

by Carl Strang

The eastern phoebe is the earliest tyrant flycatcher to appear in our area, thanks to its overwintering in the southern U.S. rather than the tropics. It won’t be long now, though the snow must go away first.

Phoebe, Eastern

Eastern phoebe

Eastern phoebe

(Initial paragraph establishing this dossier in the mid-1980’s) Phoebe locations have included the Bird Sanctuary near Culver, Indiana, along streams around Lafayette, and at Reineman Sanctuary in Pennsylvania. Usually nests have been near water (streams). The nest, built with much mud, rests on a small shelf against a wall under an overhang (e.g. on cliff, bridge or against building). They catch insects with normal flycatching foraging behavior, sallying from perches into openings. Song “fee-bee” or “fee-beehee” (last 2 syllables sounding like a hiccup), with equal accent on the 2 syllables.

21OC89. A phoebe foraged from low perches in forest, West DuPage Woods Forest Preserve (perches no more than 8 feet up).

8MR92. A phoebe called near Hartz Lake in Indiana.

6-7AP96. Phoebes are passing through in woodlands, despite the late spring: 2 together at Elsen’s Hill on a slope overlooking the West Branch of the DuPage River on the 6th, one at Fabyan Park, Kane County, on the 7th.

16OC96. Phoebe singing high in tree at Willowbrook.

1AP99. First phoebe of the year, Willowbrook.

26MR00. A phoebe foraged high in trees near the river at West DuPage Woods, flycatching a good 30 feet up.

12AP00. A migrant in the savanna at Willowbrook.

Phoebe fledglings

Phoebe fledglings

27AU00. Migrants were common today in the Natural Area at Illinois Beach State Park.

3AP02. Willowbrook. Soil blackened by the prairie burn proved attractive to the early migrant eastern phoebes, which took advantage of sun-warmed activity by insects to collect food in the prairie.

21MR04. Willowbrook. Two phoebes in the prairie.

3NO04. Willowbrook. A phoebe still present on the preserve.

MY05. Willowbrook. For the first time, nesting was confirmed on the preserve for eastern phoebes. The flycatchers built their nest in the beams beneath the bridge over Glen Crest Creek, and 4 large nestlings still were present on May 31. (They fledged by mid-June).

13AP09. Phoebes at least in migration commonly produce a loud sharp call note, “tsewp!”

5OC10. Mayslake. Singing: white-crowned sparrow, phoebe, cardinal, song sparrow.

Phoebe incubating a nest on the former friary building at Mayslake Forest Preserve. Phoebes have taken advantage of bridges and other human structures to provide foundations for their nests of mud and vegetation.

Phoebe incubating a nest on the former friary building at Mayslake Forest Preserve. Phoebes have taken advantage of bridges and other human structures to provide foundations for their nests of mud and vegetation.

6AP11. Mayslake. Phoebe calling continuously from the tip of a tree close to where they nested last year at the now removed friary. Trying to connect with mate before searching for a new spot? (The previous 2 years they had nested on the friary building. Two years ago they had 2 broods, produced only a cowbird each time).

Migrant Bird Arrivals

by Carl Strang

Today I conclude my review of early season phenology by considering arrival dates of migrant birds at Mayslake Forest Preserve. A few of these data are from late February, most are from March.

The eastern phoebe usually begins to arrive in March. This year, the first phoebe appeared at Mayslake 6 days earlier than in 2011, 11 days earlier than in 2010, and 9 days earlier than in 2009.

Bird arrival dates did not show quite the dramatic differences from previous years as did first flower dates or first insect appearances. Nevertheless, birds were showing up early in February and March. Relative to 2011, 16 bird species appeared a median 4.5 days early in 2012 (range 23 days earlier to 21 days later). The difference was larger in comparison to 2010: 15 bird species arrived a median 11 days earlier (range 0-31 days earlier). Finally, 16 bird species appeared a median 3 days earlier in 2012 than in 2009 (range 9 days earlier to 13 days later).

So far, the birds we are seeing are species that spent the winter in the southern U.S. They are expected to be much more responsive to weather conditions than the tropical migrants, which could not know about the early season. Therefore I expect differences in arrival dates to diminish as the migration season progresses.

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).

Phoebe Frustration

by Carl Strang

Late last week I was walking around the friary exclusion fence when I heard a phoebe calling.

Photo of a phoebe from an earlier year.

He was perched in the very top of a tree, close to where a pair of phoebes nested for at least the past two years at Mayslake Forest Preserve.

Their nest, built on a security light fixture, was deep in an enclosed ramp near the northeast corner of the main friary building. The light was dim, but you can just make out the incubating bird’s head.

Sadly for him, while he was spending his winter in the South, this happened.

As I related in a series of posts last fall and winter, the old friary buildings were demolished.

Was his incessant calling a displacement of his confusion at not finding last year’s nest where he left it? Was it a more practical attempt to connect with his mate so they could go house hunting? Hard to say. It seemed to be more than the usual spring calling. I have a hard time thinking of this as a tragedy, though. As far as I know, all that pair ever raised out of that nest were cowbirds.

On Monday I saw a pair of phoebes perched close together on the friary site’s exclusion fence, at the point closest to last year’s nest site. I’m inclined to think that this was the pair that nested there last year, that they have connected now, and soon they will seek a new nest site.

 I wish them good fortune in their future reproductive efforts.

Song Sparrow Dossier

by Carl Strang

I established my vertebrate species dossiers in the 1980’s as an antidote to relying too heavily on the scientific literature and the stories of others for my natural history knowledge. I wrote everything I could remember about each species from personal experience, which generally was embarrassingly little. Then I began to add notes as I made new observations to beef out the files. Each subsequent entry begins with my date code: the day of the month, two-letter month code, and year. The song sparrow’s song is one of my favorites, evocative of my childhood in a small rural town. Hm…as I read this it is clear that I still can’t say I know all that much about this shy species.

The song sparrow is one of our common birds. The dark streaks and long rounded tail are among its physical features.

Sparrow, Song

Common in weedy to brushy old fields, railroad rights-of-way, etc., around Culver, Indiana, in south central Pennsylvania, and DuPage County, Illinois. Sings from a high perch in a bush, on a weed, or in the low branches of tree. Song consists of many short, musical chirping notes, accelerating somewhat toward the end. First song in 1980 in Cumberland County, Pennsylvania, was on 19FE. A year-round resident at Culver, visiting feeders. Also in Pennsylvania. Song sparrows at McKee Marsh, Blackwell Forest Preserve (and one I heard at Waterfall Glen) have a “chew-beecha” phrase which they include in their song (note: this seems less true in recent years). That phrase has a squeaky, raspy quality, loud and interjected clashingly.

6FE87. Heard first song of year, Warrenville back yard.

22MR87. Fish hatchery, Culver. Fights frequent between song sparrows. Tumble together on the ground between short chasing flights. Vocalizations during fight a rapid-fire mix of toops, cheeps and bits of song.

11OC87. One still singing at Pratts Wayne Woods.

Song sparrow singing posture.

23MR88. A song sparrow sang from the end of an oak branch, halfway up a large tree, 15 feet off the ground, at edge of woods. Song: “chick turr, turr, turr-turr-turr, chick-tee-tiddle-tump” (last part variable). Switched to another song after a while: “cheedle, cheedle” was its beginning, but it stopped after a few of those. Throughout, alternated with a nearby male.

30JE90. Willowbrook. Some song sparrow calls have close similarity, even in tonal qualities, to some of chickadees’.

30SE99. Song sparrow at Willowbrook. Also seen 11&12OC.

27FE00. First song sparrow songs of the year heard near west branch of DuPage River at North Blackwell Forest Preserve.

4MR00. Morton Arboretum. A song sparrow displaced another and then sang, in brush beside a pond.

31MR00. Waterfall Glen. A song sparrow singing in tops of isolated 8′ shrubs beside railroad. Did not lift head to sing, but held head normally at 10-20 degrees above horizontal and maintained that angle while singing.

29AP00. Morton Arboretum. The call note is sharply bounded on each end, doesn’t trail off, is very high pitched.

Song sparrow nest on the ground in meadow area, Mayslake.

18JE00. Herrick Lake. A pair was very nervous about my presence, and though one had an insect in its beak they would not go to the nest though I was 20 yards away. A pair at Willowbrook earlier in the month behaved the same way.

22OC00. Song sparrows singing at Blackwell Heron Trail area. Some also were singing in Culver yesterday and the day before.

11MR01. Song sparrow singing at Timber Ridge Forest Preserve.

13OC01. Several at McKee Marsh.

22OC01. Several song sparrows singing, sometimes seeming to answer one another. Heron Trail, South Blackwell Forest Preserve.

3NO01. A single song sparrow song at Herrick Lake F.P., near big south marsh.

12OC02. At Fermilab, 2 kinds of calls from different individuals in different places. One had calls indistinguishable from the high one of white-throated sparrow. Bits of song, too. Another individual, perched in the open on top of a bush, exposed, had a call much like house sparrow’s.

Summer 2008. Song sparrows were among the species at Fullersburg raising cowbird young.

5OC10. Mayslake. Singing: white-crowned sparrow, phoebe, cardinal, song sparrow.

Northern Cardinal Dossier

by Carl Strang

This time I share my dossier for a common and beloved species. As usual, it begins with the general account I wrote when I established the file in the 1980’s, then additional entries begin with my date codes.

Cardinal, Northern

The cardinal is the first bird I studied with any intensity, as a child mapping song perches of males in my neighborhood and connecting them into “territories.” Generally they selected highly exposed perches in treetops and on television antennas. The song is highly variable, but tonal qualities of voice and type of song pattern are distinctive. The alarm note is a sharp “teek,” again of a distinctive tonal quality and pitch. The female also sings, the songs following the same pattern as the male’s but sometimes lower in volume.

They nest usually in thick bushes within 10 feet of the ground. A nest at Boiling Springs, PA, was in a rain gutter closely overarched by spruce branches. Young birds in a brood observed in Lombard, IL, were kept together and off the ground by the parents.

Both sexes have bright red beaks surrounded by black feathers. When viewed head-on this has an imposing effect, the bird’s weapon thus being highlighted. No doubt this is of significance in agonistic display. Field guides, with their emphasis on lateral views, lead us away from this kind of discovery.

Cardinals feed in bushes, in trees, and on the ground. They are not acrobatic foragers. They consume large seeds at feeders in winter. Cardinals appear to show some territoriality through winter.

Songs vary among locations, individuals, and times. Each male has more than one song. Some rendered songs are: “chibone, chibone, chibone, chibone;” “What-cheer, wheet wheet wheet wheet;” they beging singing in late January (as early as 23JA83 in DuPage); “pul’see pul’see …” (~7 reps).

17JL84. Male foraging in black cherry tree spent 5-8 sec. on a perch, moving head to look at nearby leaves and twigs in small turning movements, moving 0.5-1m between perches (Willowbrook Back 40).

NO84 they were often feeding on ground, scratching in leaves.

12FE87. Heard first song of year.

5MY87. Nest with 3 eggs, of twigs (slightly loose structure) beside trail in riparian strip at Willowbrook. In honeysuckle, 5 feet up, in fork of branches. Deep cup. Eggs bluish with brown mottling. By a few days later only one egg left, nest apparently abandoned (too close to trail?).

5JE88. In the middle of Geneva I stood under a tree in which a pair of Cardinals suddenly began to alarm-call rapidly. They were close to me, but not paying attention to me. The calls were directed at a blue jay which the cardinals chased from the isolated streetside tree to a clump of trees and brush, and continued the alarm calling and chasing until the jay left. The jay resisted some, was not driven off easily.

19JA89. First Cardinal song, on Willowbrook early morn. In an unusually warm January.

9MR89. Cardinals all singing today through midday (first warm day, 40 degrees F, after a long cold spell). There seem to be too many Cardinals singing, and I see 3 males chasing each other. In this year with such a mild January and no super-severe weather, unusually high survival?

17AP89. A cool, cloudy day. Cardinals all over the Back 40 are giving constant series of “alarm” (?) notes.

29JA90. First cardinal song of year, Willowbrook.

1990. The year of the 17-year cicadas, I caught some at Fullersburg and released them at Willowbrook. One of these flew across a small forest clearing, and a cardinal flew out and caught it with its beak, in mid-air.

26JA99. First cardinal song of year, Willowbrook.

4MR99. Many cardinals singing at Willowbrook, including a female near the Nature Trail head.

3MY99. Cardinals fighting in area of white cedars at Willowbrook.

13MY99. Cardinal nest at Willowbrook in honeysuckle shrub overhanging creek. May still be under construction, though birds agitated when someone is nearby. Female incubating 17MY, 27MY.

10AU99. Cardinal songs distinctly reduced in number, length. Only a few weak, partial songs this morning.

25AU99. Last cardinal song of year noted at Willowbrook.

26AU99. Cardinal fledgling, with rapid notes, similar in pitch to adult’s note but not as sharp, and rapidly repeated rather than separate.

1NO99. Cardinal eating buckthorn berries. 

14JA00. Cardinal sang a half song in afternoon, Willowbrook.

2FE00. First full cardinal song of year, Willowbrook.

21FE00. McKee Marsh, north Blackwell Forest Preserve. A male cardinal singing from a very exposed perch at the top of a 25-foot-tall cottonwood. Doesn’t change posture much when singing. Thrusts face forward a little, but keeps bill level. Sang back and forth with other audible cardinals, answering with full songs, “What-cheer, wheet wheet wheet wheet.” The others stopped singing, it paused for some seconds, then gave a “what-cheer,” paused, did so again, and gradually added “wheet” syllables until it was singing full songs again, even in the others’ absence. When not singing, turned head to look all around.

25FE00. Willowbrook. Several juncos and cardinals singing this morning. A display by a male cardinal that was singing at the service road junction with the Nature Trail. A female was in the same tree, and for a minute or two the male faced her, occasionally adopted an extended, stretched out body posture unlike the normal singing pose, moved with body held rigidly, and emitted a chattering dry trill between some of the songs, all the while facing the female. She stayed in place, he never approached within less than 5 feet, and he then turned away from her and resumed singing normally.

1JL00. A female yellow warbler feeding a cowbird fledgling near the south end of Silver Lake, Blackwell. Earlier this week a pair of scarlet tanagers were feeding 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 involved) also at Willowbrook.

2SE05. Had to re-learn fledgling call of rapid high notes lacking sharpness of adult alarm. May have been contact call rather than alarm, though adult nearby gave very occasional alarm, too.

7JA08. Fullersburg. A cardinal sang, briefly and uncertainly, but definitely. My earliest noted song (previous earliest 14JA00). Temperatures in the 50’sF past couple days.

15JA10. Culver. First cardinal song of the year.

5OC10. Mayslake. Singing: white-crowned sparrow, phoebe, cardinal, song sparrow.

7DE10. Mayslake. A cardinal singing, full strong song repeated a couple times. Sunny day but cold, teens F. (I have heard cardinals singing on occasion all through the middle of this winter, the first time I have observed such an extended singing period).

Another observation in recent years is that cardinals in our area seem to raise mainly cowbirds early in the season, but a final August nest nearly always produces only cardinals. If this is correct, it implies a strong selective pressure, at least locally, for shifting the nesting season later.

Friary Demolition Begins

by Carl Strang

One day last week I drove into Mayslake Forest Preserve and saw something new sticking out above the trees.

The time had come for the friary to be demolished. The building was constructed during the property’s time as a Franciscan center. On the outside it is interesting looking.

Inside, by all accounts, the friary has become rotten, deteriorated past recovery, and could be regarded as an attractive nuisance. Demolition is beginning with the outbuildings.

I have not heard how the land is to be restored once the building is gone. Naturally I will follow that with interest. The friary was housing a raccoon, and during the breeding season its walls supported nests for a pair of eastern phoebes and a few chimney swifts. Whatever habitat replaces the friary will be home to a greater diversity of life.

There has been some confusion. The friary is not the Peabody mansion or the retreat wing which the Franciscans appended to the mansion. It is not the chapel. Those buildings all are safe, and much in demand for Forest Preserve District programs as well as rentals.

Bird Arrival Dates Through April

by Carl Strang

Two days ago I reviewed flowering phenology at Mayslake Forest Preserve, which demonstrated that spring is progressing about two weeks ahead of last year. Today I want to consider whether migrant birds are showing a similar pattern. There are two questions that interest me. First, is there a difference between species that winter in the tropics versus those with at least a significant presence in the southern U.S.? If weather is a factor, we might expect the closer birds to be more responsive. Second, did the U.S.-wintering species arrive earlier in March and April this year than last? Here’s one of those species, an eastern phoebe, already incubating a nest at Mayslake.

As of the end of April, not many tropical migrants had arrived. All four of those that I observed were within 6 days of their last year’s arrival date (two were earlier, two later; median 1.5 days earlier). Since they are responsive to physiological clock and day-length signals that are the same between years, this is the kind of tight pattern I would have expected.

The 27 species that wintered in the southern U.S. showed a lot more scatter, with arrival dates ranging from 40 days earlier to 21 days later. The median difference was only 2 days later, however, which leaves me thinking that these birds, as a group, likewise did not respond to the early spring. This, like the flowering phenology, I will want to follow in future years, with the elaboration of looking at the data on a species by species basis.

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