American Tree Sparrow Dossier

by Carl Strang

Today’s feature is my dossier of the American tree sparrow, a wintering bird that still is with us but soon will head back to the northern nesting grounds. The following notes reveal my interest in the complex range of this species’ vocalizations.

American tree sparrow. The black spot in the clear chest is a helpful identification feature.

American tree sparrow. The black spot in the clear chest is a helpful identification feature.

Sparrow, American Tree

This songbird is a common winter resident in old fields and residential areas with some bushes, in Culver, around Lafayette, in south central Pennsylvania and in DuPage County, IL. Usually they occur in loose flocks, often mixed with juncos. They feed on the ground, especially, taking seeds. Note: “tsew,” “tsoo” or “tsee” in a slightly melancholy minor key, hint of downward slurring. Has a 3-syllable call, a hair slower and more flowing than junco’s, very musical and pleasant in contrast. Single-note call has a descending tail, is much like white-throated sparrow’s.

26FE87. Song heard in Willowbrook Back 40: “Tsoo-too-doo-doo-dee-chew-chew-chew-chew.” Song loud and clear, of water thrush quality.

7MR87. Another song: “tsee-tsoo-bye-tsee-tsoo-tsoo.” First note held longer than others. Tsee syllables highest pitched, tsoo’s lowest. Sang from perch in top of willow clump, 6 feet up, at West Chicago Prairie.

13MR87. Still hearing them singing.

22MR87. Still present and singing at Culver Fish Hatchery.

15OC99. First tree sparrow of the season at Willowbrook.

20DE99. Tree sparrows eating Indian grass seeds at Fermilab. Sometimes their call notes are simple and flat, but sometimes they add a trailer that so far I cannot tell from white-throated sparrow’s. In conflicts they have beautiful, musical clusters of notes.

29JA00. A flock of 30 tree sparrows and 2 juncos feeding on the gravel berm edge of Swenson Road, Fermilab.

5MR00. A single still at Fermilab, in thick grass area with a few shrubs, beside trail.

The red on the top of the head, the white wing features and yellow lower bill mandible are additional distinctions.

The red on the top of the head, the white wing features and yellow lower bill mandible are additional distinctions.

23NO04. Willowbrook. A flock of tree sparrows in tall prairie vegetation using a call I don’t remember hearing before, a pardalote-like “wee’dah.”

16NO10. Mayslake. Many tree sparrows are in the west stream corridor along the southern edge of the mansion grounds. Giving an unusual call, less than a second long, beginning at a high pitch, slurring to a lower one, and quickly back up to the starting pitch.

6JA11. The more complex tree sparrow call can be difficult to pick out when many birds are producing it at once. When a single bird is isolated, the call has the rhythm of a quick, “tit willow,” i.e., three dominant syllables with the last two close together and a little more separated from the first.

2FE12. American tree sparrow call: dedjidu, quickly pronounced.

15NO12. Mayslake. Tree sparrows eating seeds of Canada goldenrod and annuals.

25JA13. Mayslake. On the ground in the off-leash dog area, an enormous flock of at least 100 tree sparrows, 30 juncos with at least one white-throated sparrow mixed in, doing the double-foot scratching to get through the snow and then reach, presumably for seeds.

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Mayslake Update

by Carl Strang

Mayslake Forest Preserve has been quiet, and for the most part remains in winter mode. Large numbers of American tree sparrows still are present, though they are wandering into an expanded portion of the preserve. For instance, one day in late January they shifted to the off leash dog area and, joined by some juncos, a couple song sparrows and a white-throated sparrow, fed on weed seeds.

Here is one tiny portion of the flock that contained more than 100 tree sparrows. One of the song sparrows is in the center.

Here is one tiny portion of the flock that contained more than 100 tree sparrows. One of the song sparrows is in the center.

In another part of the flock the tree sparrows are joined by a few juncos.

In another part of the flock the tree sparrows are joined by a few juncos.

At long last the stream corridor marsh has begun to refill.

A tiny, shallow pool had gathered by January 29.

A tiny, shallow pool had gathered by January 29.

That initial pool was perhaps 30 feet across.

That initial pool was perhaps 30 feet across.

A front brought heavy rain, then cold that froze the collected waters.

Here is the marsh two days later.

Here is the marsh two days later.

We continue to get periods of rain, and the river bulrushes have begun to collapse.

By the end of last week, perhaps 80% of the marsh had water in it again.

By the end of last week, perhaps 80% of the marsh had water in it again.

With the ground frozen, much of the rain is running off, but some is collecting in depressions like the marsh. We can hope for the rain to continue and perhaps avoid a repeat of last year’s drought.

In the meantime, skunk tracks have begun to appear, one of the early signs that spring is coming.

Some Mayslake Winter Birds

by Carl Strang

Yesterday I posted an update on the goose roost at McDowell Forest Preserve. At the other end of the county, a large flock of Canada geese roosted in a hole they kept open at Mayslake Forest Preserve. This probably was the group whose center of operations in midwinter is Salt Creek at Fullersburg Woods Forest Preserve, a mile or so farther east. Lake roosts last only as long as daytime temperatures are warm enough to keep the holes open when the geese leave to feed. That opportunity ended with the recent cold spell.

The location of the former hole is marked by the snow-free patch of ice in the center of Mays’ Lake.

The location of the former hole is marked by the snow-free patch of ice in the center of Mays’ Lake.

More than 300 geese rested on the Mays’ Lake ice at mid-day last Thursday. I am guessing that they shifted their overnight roost to Fullersburg when the lake froze, and were using Mays’ Lake as a mid-day resting place.

They stood mainly where the hole had been.

They stood mainly where the hole had been.

This is supported by their flying west after taking off for their afternoon feed. Mayslake is closer to their feeding areas than Fullersburg, and saved them a couple miles’ flying. On the other hand, they did it only the one day.

Meanwhile, up at the former friary site, a large flock of American tree sparrows has taken up its early winter residence.

The brushy western edge provides safe shelter.

The brushy western edge provides safe shelter.

The friary site is filled with weedy seed-bearing plants.

The friary site is filled with weedy seed-bearing plants.

Tree sparrows are inclined to wander in winter, though, so I am not assuming they will be there through the entire season.

Tree sparrows are inclined to wander in winter, though, so I am not assuming they will be there through the entire season.

Otherwise, Mayslake is very quiet these days.

Bird Habitat Preferences: Winter Residents

by Carl Strang

The dark-eyed junco may be our most familiar winter visitor among the birds. They nest in Canada and the northern states, so we see them here only from September to April. 

Juncos are gray and white sparrows, close enough relatives of white-throated sparrows that the two occasionally hybridize.

Their nesting habitat is forests, especially forest edges. What do they prefer in winter? Yesterday I showed how two local breeding birds prefer woodlands, to the near total avoidance of open areas. Such is not the case for juncos. At Mayslake Forest Preserve over two years I have a total of 36 observations in open habitats, 307 in savanna, and 61 in forest. Expectations based on the proportional acreage in those habitats are 125, 174 and 105, respectively. Though they spend some time in the open, and some time in forest, like Goldilocks they find the intermediate mix just right. Given that their winter diet is mainly seeds they pick up off the ground, this is not surprising as savannas provide both seeds and shelter, forests provide shelter but fewer seeds, and open areas have abundant seeds but limited shelter of the kind juncos like.

The other winter species for which I had enough data to look at habitat preference is the American tree sparrow.

The black spot on the chest, red cap, and 2-toned bill distinguish the American tree sparrow.

Here the observations number 62 in the open, 55 in savanna, and 37 in forest. Corresponding expectations based on habitat areas are 48, 66, and 40. It will come as no surprise to readers familiar with this species that the open appears to be preferred, but these observations are not far from the expectations and in fact the difference is not statistically significant. It appears that the tree sparrows are taking full advantage of the seed stocks available in the open as well as the shelter provided by wooded habitats. They nest north of where juncos spend the summer, in open tundra areas and zones of mixed tundra and scattered trees, so the differences between the two species on their wintering grounds are consistent.

Mayslake’s Winter Birds

by Carl Strang

An interesting mix of bird species wintered on Mayslake Forest Preserve this season, through the storms and the cold. Among them was a yellow-rumped warbler that mainly was active around the south and east shores of May’s Lake.

This warbler often chowed down on the berrylike cones of red cedars.

There always seemed to be jays around, and sometimes when a few became agitated their calls drew in as many as 10 of their kind.

I didn’t see the jays feeding, but there was a good acorn crop last fall and my guess is that the jays stored a sufficient supply.

Some winter residents were steady, and expected. These included cardinals

Cardinals sang for an unusually extended period this winter.

and juncos.

Mayslake’s juncos wandered widely, and I never got a sense of how many groups there were or how their home ranges were distributed.

American tree sparrow numbers fluctuated greatly, but there always were at least a few around. A common redpoll showed up one day and was gone the next. There also were rare appearances by white-throated sparrows.

I saw white-throated sparrows so seldom that I think they were wanderers rather than residents.

Though no red-winged blackbirds have shown up at Mayslake yet, I have seen them elsewhere in DuPage County and expect some at Mayslake any day. An equally sure sign of the transitional season was the arrival of this Canada goose pair at the stream corridor marsh yesterday.

Sure enough, the male had a band on his left leg. I take it that this is the same pair that nested successfully on the preserve last year. I saw no sign of the two surviving young that were with this pair the last time I saw them in the fall.

I am so ready for spring and the progression of migrants. Bring it on!

Recent Animal Activity

by Carl Strang

Autumn has transitioned to winter at Mayslake Forest Preserve. Sandhill cranes still were migrating in late November, and I wouldn’t be surprised to see more before the end of the year.

But most migration seems to have passed to our south. Sparrow flocks have been stabilizing.

Last week the first bit of sticking snow drew my eyes to the ground. The season’s first snow tracks were a cottontail’s.

Then, over the weekend we got our first covering snow, 3 inches worth.

But even in winter there can be surprises. On December 7 I heard a cardinal singing.

This is one reason to build species dossiers. Consulting mine, I could find no record of a singing cardinal between October 15 and January 7 in past years. Usually they are done in August and don’t start up again until the second half of January. This is a true oddity. Cardinals are relatively sensitive to changes in daylight hours, and usually can be counted on to start singing before the end of January, but in early December the days still are shortening.

Mayslake Birds

by Carl Strang

Birds still are showing migratory activity at Mayslake Forest Preserve in the second half of November. As I wander the preserve early in the morning or on my lunch break, the birds I find often are changing significantly from one day to the next.

Some, like the golden-crowned kinglet in the photo, come and go day to day. Others may be settling down, as they are present each day and their numbers are more stable. These include dark-eyed juncos and American tree sparrows.

One promising sign that this may be a livelier winter than last is that I have seen pine siskins on three occasions. There were none last year, but the winter before last was a good one for winter finches from the North. That will make for a more interesting season if it happens again.

Winter Departs from Mayslake

by Carl Strang

The time has come to say farewell to winter. At this time of year most of us are glad to turn our backs on the coldest season, but it had its beauty. Here are some views of Mayslake Forest Preserve’s stream about a month ago.

A forest preserve district crew took advantage of the frozen ground to clear unwanted brush from part of the 31st Street Woods.

The ice finally melted away from May’s Lake in mid-March.

Enjoy the American tree sparrows. They won’t be with us much longer.

The traces of last year’s nesting season remain, including this Baltimore oriole nest (first mentioned as it was built, here).

Here’s the current state of another old oriole nest.

This is the one a squirrel helped me find. It also is the one that produced a cowbird. Winter traditionally was a time of storytelling, and seeing those nests has brought back their stories to me through the winter. But now I’m looking forward to the return of the orioles from the south, and the coming season’s new stories. In the meantime Maylake is experiencing many earlier signs of spring that I’ll share in the next post.

A Slow Start to Winter

by Carl Strang

Compared to last winter, this has been a slow one at Mayslake Forest Preserve in terms of animal activity. Last year, flocks of siskins and occasionally of white-winged crossbills frequented the preserve’s conifers. This year there have been only the year-round resident birds joined by a few American tree sparrows, and birds generally have been quiet.

Coyotes have been active, and we have seen them more frequently. I saw three together once, so at least one of last year’s pups has stuck around. Their tracks indicate the animals usually hunt individually, however.

In the deeper snow of January, the coyotes as always took advantage of human footprints and other depressions to make their own travel easier.

I did not see any mink tracks until January 12, where an individual was traveling along the little stream and went up onto the bridge.

Muskrats, as I believe I mentioned in an earlier post, have gone more to mound nests than to bank tunnels this year. There are two of these in the parking lot marsh.

A single such den in the stream corridor marsh projects only a little above the ice, and that animal may have been forced into a bank den.

I continue to enjoy my lunchtime walks on the preserve, and always am hopeful that I will find interesting animals or signs of their activity.

CBC 2009

by Carl Strang

One annual highlight as the end of the year approaches is the Christmas Bird Count. Last year I introduced the group to which I belong. Here our party proceeds along the Prairie Path in the 4-mile hike that filled Saturday morning.

Urs Geiser, our leader, is on the left. Behind him, Frank Padera converses with Marcia Nye (who walks behind a smiling Linda Padera). Lee Nye’s clipboard reveals that as recorder he had the challenge of keeping the data sheet dry. A very light snowfall was a constant through the day. Judy Morgan was with us, too, but doesn’t show in this photo. Chuck Drake couldn’t make it this year.

As you can see, the accumulated snow made the landscape beautiful.

The beauty had to compensate for a relative absence of birds. Nearly every species was down in numbers compared to last year, and to the area’s average. One species that was present in typical numbers was the American tree sparrow.

Among the 29 species we found were a few robins.

On the other hand, there were a few highlights. We saw our area’s first tufted titmouse in years (but no photo). Also, the area’s first-ever hooded merganser and coot (the latter shown below) cheered us in the afternoon.

I should clarify that when I refer to “area” I mean the bit of geography assigned to our little group. Our area was part of a much larger circle centering on Fermilab and covering significant parts of DuPage and Kane Counties. Ours was one of eight groups collectively covering that circle. Circles like this are one part of the continent-wide standard that allows CBC data to have some merit in long-term monitoring of birds across North America.

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