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.

Canada Goose Roost Shift

by Carl Strang

Over the last two winters the Canada geese wintering in DuPage County have, on the whole, continued the pattern of activity I have described in the past (for instance here). This winter one of their roosts had to move, thanks to mitigation and restoration work in the West Branch of the DuPage River at McDowell Forest Preserve. The roosting area used to be the large shallow pool created by the old McDowell dam.

Geese at the former roost area prior to departing for the morning feed.

Geese at the former roost area prior to departing for the morning feed.

Dredging to remove toxic thorium from the riverbed, coupled to notching the dam and reconfiguring the channel, have eliminated that pool.

The site of the former pool, which will improve in appearance over time.

The site of the former pool, which will improve in appearance over time.

Not far downstream from the old McDowell dam is the Fawell Dam, a more modern flood control structure. It allows plenty of water to flow through, but it widens the river enough to provide a new safe roosting area which the geese now are using.

Geese in their new roosting area.

Geese in their new roosting area.

On January 1, when I visited McDowell and took these photos, I was surprised when some geese in the channel near the former roost came up onto land and approached me.

Hm, I thought, someone’s been feeding you, haven’t they?

Hm, I thought, someone’s been feeding you, haven’t they?

I told the geese they were out of luck with me.

One pair settled practically at my feet and began to nibble at grass seedlings.

One pair settled practically at my feet and began to nibble at grass seedlings.

At least that was a safer, more nutritious diet than they are likely to be getting from handouts.

Ready and Waiting

by Carl Strang

The parking lot marsh at Mayslake Forest Preserve holds many muskrat mound houses this winter.

Two large mounds are plainly visible in the north end.

In each of the past two breeding seasons the only Canada goose nest on the preserve has been on a muskrat mound in this marsh. Thanks to presence and absence of leg bands, I know that it has been a different pair each year. Both nests were successful. Three seasons ago the muskrats had only bank dens, the water was shallower, a pair of geese nested on a low, exposed island, and the preserve’s pair of coyotes waded out and killed the incubating female and got her eggs.

Here are 3 more mounds in the center of the marsh.

With so many potential platforms this year, there is the possibility that more than one pair will nest there.

Add one more in the south end.

It’s not a big marsh, though, and an aggressive pair of geese may be able to keep others out. I’ll be interested in seeing what develops.

For the moment, Canada geese still are in their winter pattern. I have not followed them as closely this winter as in past years, but clearly more roosts have stayed active and more birds have hung around in this milder season. I checked out the Blackwell roost earlier this week, and found that though the geese continue to use it, the water has been drawn down.

Most of the roost area is in mudflats.

This is not simply the result of low precipitation.

The gate has been removed from the dam. There are plans to enlarge the zone of marsh-edge vegetation.

This could be a good place to see migrant shorebirds later in the spring.

Fox River Goose Check

by Carl Strang

I have not had much time to check Canada goose roosts in DuPage County this winter. On the surface, at least, it appears that the pattern of recent years has been repeated, with severe cold freezing up most of the roosts in December (Hidden Lake exceptional) and pushing most geese out of the county. On New Year’s Day I found the Blackwell and McDowell roosts still empty despite being newly re-opened by a thaw. Remembering my observations at the Fox River last year, I drove out there on the morning of the 2nd. I found no large roosts, but there were numbers of geese in smaller groups along the river’s edge. At Red Oak Nature Center, a couple hundred birds could be seen.

Canada geese rest on ice at the edge of the Fox River while floes pass on a cold morning.

I was impressed by common mergansers as they dodged the newly formed ice floes and dove after fish in the frigid river.

Common mergansers stay close to the edge of open water in winter.

Another place I found geese both last year and this was at Glenwood Park Forest Preserve just south of Batavia.

Several hundred geese lined the shore across from Glenwood Park Forest Preserve.

People have been reporting bald eagles along the Fox River all winter, so it was invigorating, if not surprising, to have one perch nearby as I surveyed the geese.

One of the more positive developments of recent decades has been the increase in bald eagle numbers.

As far as I can tell, these geese are feeding mainly in Kane County, and so I am limited in what I can learn in DuPage for now.

Christmas Bird Count 2010

by Carl Strang

Saturday was the DuPage Birding Club’s Christmas Bird Count, which centers on Fermilab, the famous physics research facility that straddles western DuPage and eastern Kane Counties. Here my group pauses attentively as yet-to-be identified birds call and flutter in the brush.

Group leader Urs Geiser, far right, is very good at pishing, a method for calling in small birds.

For a group portrait go here to the account of the 2008 outing. The weather has been very cold, most bodies of water are frozen, and for the most part the count was unremarkable. One exception for our group was this purple finch that Linda Padera spotted just before our lunch break.

The heavy facial stripes distinguish the female-plumage purple finch.

In the afternoon we stopped at West Branch Forest Preserve, home to one of the county’s major Canada goose roosts until it freezes over. Some birds had kept a hole open in the ice.

Most of the birds around the hole are Canada geese.

While we watched, the main swimming activity keeping the hole open was provided by 14 common goldeneye ducks and a coot.

Here, 8 of the goldeneyes rest on the surface between foraging dives.

On the ice fringing the nearby West Branch of the DuPage River, we noticed these remarkable traces in the snow.

What do you think would make marks like this?

A close look revealed distinctive footprints of a great horned owl close to the bank. It looks like the bird came in for a landing at speed, with most of the lines drawn by the bird’s tail feathers as it put on the brakes. Undulations suggest the owl made two strong backsweeps with its wings as its tail feathers dragged. It stood for a moment before springing back into the air.

Geese Shift Gears

by Carl Strang

The goose family from the parking lot marsh nest returned to Mayslake Forest Preserve’s mansion grounds for a few days in mid-September. Dad is recognizable by the band on his left foot, the two surviving kids can fly now.

For now they are staying to themselves, but the last two weeks have seen goose families across DuPage County coalescing into flocks as they shift toward their winter pattern.

Last Friday this flock on Rice Lake at Danada Forest Preserve numbered close to two hundred birds. The coming couple months will see such flocks build on many lake, river and marsh roosting grounds. From there they will radiate out to lawns and fields to feed during the day. Soon they’ll be joined by northern geese, and the flocks will build to their peak sizes until the freeze concentrates them on the major roosting sites, at which time some will shift south. After that, much depends on the severity of the winter. Winter may not be my favorite season, but the past couple of years I have been enjoying my study of Canada goose winter behavior. As the weather turns frosty I can at least look forward to learning whatever new lessons the geese will have to teach me.

The Geese Say It’s Spring

by Carl Strang

Circumstances have prevented my following DuPage County’s Canada goose roosts as well as I would like this winter, but the weather and observed behavior both seemed similar to the winter of 2008-9. The roosts nearly all froze over in January, except for the Hidden Lake roost on an expanded portion of the East Branch of the DuPage River. Most geese departed the county, either for downstate Illinois or possibly for open portions of larger rivers, as I mentioned earlier.

By the end of January, open water had reappeared at some roosts, and some geese returned. At Blackwell, for instance, where 2500+ geese had been present in mid-December, the number dropped to 300 in the first half of January when the roost was reduced to a relatively small pool of open water. Thawing raised Blackwell’s numbers back to 1500 by month’s end, and that number held in the first half of February. Geese began to disperse from that roost by February 20, when the number had dropped to 1100, and there were only 700 on March 1. The McDowell roost followed a parallel pattern, with the roost freezing over and pushing out the geese entirely for much of January. At Hidden Lake, mid-December numbers of 2000+ had dropped to 1100 by January 1, but then remained roughly constant through the rest of the winter. As that roost remained open, its reduced count on New Year’s Day probably represents the end of migration.

The diminution of numbers in the last half of February was accompanied by changes in the birds’ behavior. Increasingly, pairs were appearing around potential nesting sites, or at least breaking off from the flocks, as this grazing pair at Mayslake Forest Preserve exemplifies.

I didn’t realize that one of these birds was banded until I downloaded the photos.

March thus brings the end to the winter roost pattern and the start of the breeding season for DuPage County’s Canada geese.

Fox River Geese

by Carl Strang

As I have monitored the comings and goings of Canada geese in DuPage County over the past two winters, I have assumed that when deep snow and frozen roosting areas force birds out of the county they have been heading south to warmer locations in downstate Illinois. This assumption has been supported at times by observations I have made and reports on IBET (the Illinois birding e-mail list) of high-flying flocks of southbound geese. In the back of my mind, however, has been the possibility that some of the departing birds may not be going all that far, perhaps taking temporary roosting spots along the Des Plaines River or the Fox. Last Sunday morning I decided to check out reports of large numbers of geese roosting on the Fox River west of DuPage County. I made stops along the stretch of river closest to the Blackwell roost, because of the possibility I might spot either the leucistic bird or a numbered orange neck collar belonging to a recognizable individual.

I found thousands of geese roosting along the Fox between Fabyan Park (south Geneva) and the north part of the city of Aurora. There were scattered small groups like the one shown above, but also some enormous ones. Here is a fairly large group opposite the Red Oak Nature Center.

Just downstream from that group was a larger one.

Largest of all was a roosting group on an ice shelf just above the North Aurora dam.

Though I didn’t spot any recognizable individuals, I plan to return from time to time in the future. I couldn’t see every part of that stretch of river, and I also want to gain some sense of how the number dynamics along the river correspond (or not) to those in DuPage roosts I have been following.

Geese Going and Coming

by Carl Strang

Canada goose numbers in DuPage County have been changing dynamically over the winter to date. Today I’ll share numbers from the roosts I have been following most consistently.

Blackwell roost

The Blackwell roost in west central DuPage had built to more than 1000 birds by mid-October, and peaked at 3500 in mid-December. Then came a severe cold snap that froze lakes and parts of streams, closing many of the scattered smaller roosts on lakes. On January 1 the Blackwell roost was down to 300 birds, the majority apparently having shifted south. That count was constant at least through January 9, by which time deep snow limited the birds’ access to food. By month’s end, however, a warming period had melted the snow and opened roosts up again somewhat, and the Blackwell roost had increased to 1500 geese.

McDowell roost

 The McDowell roost, a little south of Blackwell, showed a parallel pattern. The peak count of 760 birds in mid-December dropped to 90 on January 1, and the roost was empty on the 9th. On January 31 the moderating conditions had brought back 90 geese.

Hidden Lake roost

Last year, Hidden Lake in central DuPage County retained the most Canada geese through the winter, and the same has been true this season. That is not to say, however, that all the birds have remained there throughout. After a peak of 2500 geese in mid-December, the Hidden Lake roost dropped to 1100 on January 1, I made an exact count of 937 on January 9, and the rough count of 1000 indicated constancy to January 30.

Fullersburg roost

I have only two counts for Fullersburg this winter, and those suggest a break from the pattern described above. On December 29, when other roosts were at their lowest, I counted 670 geese at Fullersburg, and a month later, when other roosts had increased their numbers substantially, the Fullersburg count was only 385.

I’ll continue to follow these roosts through the rest of the winter.

The Fullersburg Roost

by Carl Strang

The main Canada goose roost in east central DuPage County is on the stretch of Salt Creek adjacent to the Fullersburg Woods  Forest Preserve visitor center, between Willow Island and the Graue Mill dam.

On December 29 I counted 670 geese scattered in groups along this roost area. In previous winters I have counted as many as 1100 in February of 2006, 2700 in January 2007, and 870 in December 2007. The pattern has been that the geese build in numbers through the winter, probably by adding geese when the surrounding lakes freeze.

Sometimes in periods of extreme cold, that relatively calm section of Salt Creek ices over, however, and the geese depart. I’ll need to return to that roost later in the winter to see if the pattern holds.

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