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.

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SJF February Summary

by Carl Strang

Beginning in the middle of the month, I went through all of St. James Farm Forest Preserve seeking the great horned owl nest. I did not find it, but did create an inventory of 25 large tree cavities where an incubating owl might not be visible from the ground. An additional possibility would be a hawk nest in the dense top of one of the spruces. Twice I saw an owl, presumably the male if they are nesting this year, in the same north central portion of the main forest. In past observations elsewhere, the male usually perched in the vicinity of the nest. I will continue to monitor the suspect cavities, but may need to see branched young later in the season to narrow down possibilities further.

I was able to eliminate this cavity, as it was otherwise occupied.

I was able to eliminate this cavity, as it was otherwise occupied.

Some photo processing in the computer makes the raccoon easier to see.

Some photo processing in the computer makes the raccoon easier to see.

I had not seen or heard a pileated woodpecker on the preserve for more than 6 weeks (though occasionally I heard suspicious loud, spaced tapping sounds), but in the second half of February heard or saw one on three different days. The one close sighting was of a male.

The pileated’s tongue-spear in action.

The pileated’s tongue-spear in action.

American coots and large numbers of mallards were a continuing presence on the stream. For much of the month the Canada geese roosting at Blackwell frequently passed over St. James Farm in large numbers, occasionally stopping to graze the lawns and meadow areas. Geese began to break off into pairs as ponds opened up during the last third of February. Interesting bird sightings included a bald eagle flying over, and a hermit thrush on February 16. Migrating sandhill crane flocks began to pass over beginning on the 21st. A small group of white-throated sparrows in the eastern part of the main forest were the first observed on the preserve this year. The first red-winged blackbirds arrived, and eastern bluebirds became a more consistent presence in the last part of February.

This male eastern bluebird seemed to be staking a claim in a corner of the grounds adjacent to a pair of bluebird houses.

This male eastern bluebird seemed to be staking a claim in a corner of the grounds adjacent to a pair of bluebird houses.

Fox squirrels fed heavily from Norway spruce cones in the south forest, and on tree buds elsewhere. Skunk and deer activity was much as described for January. The preserve’s deer minimally are a group of 3 does, a group of 2 deer which occasionally associate with those does, and a single buck. The snow was never deep enough to discourage raccoons. A mink used a den off the south edge of the pond in the preserve’s northwest corner.

Along the way during the owl nest search I found this curiosity.

Along the way during the owl nest search I found this curiosity.

The deer pelvic bone was well gnawed by rodents.

The deer pelvic bone was well gnawed by rodents.

The bone has been on this buckthorn twig long enough for the twig to grow several long branches.

The bone has been on this buckthorn twig long enough for the twig to grow several long branches.

The large area of restoration brush clearing in the main forest was expanded greatly by District staff, generally following the route of the new trail mapped in the preserve’s master plan. Among the more interesting plants encountered during the owl nest search were two of the most massive black walnuts I have ever seen, and a prickly-stemmed greenbrier (Smilax tamnoides).

American Coot Species Dossier

by Carl Strang

This week’s featured species is a water bird that was an iconic migrant in my childhood, appearing in huge, raft-like flocks on Lake Maxinkuckee during the spring and fall migration seasons. Then, we often referred to them by the old hunter’s name: mudhens.

American coot

American coot

Coot, American

This rail relative is a migrant and rare summer resident on Lake Maxinkuckee at Culver, Indiana. They migrate at night, spending time on the lake in large rafts of up to hundreds of birds. Occasionally some come onto shore to graze, but usually they dive for aquatic plants in water 1-15+ feet deep, close to or far from shore. They run on the surface to take off, and their landings are not particularly graceful: they fly to within a couple feet of the surface, stop flying, and plunk into the water. Coots breed in cattail marshes with some open water, making nests in the cattails. Their vocalizations in migration consist of simple soft, high-pitched peeps or chuckling sounds. On breeding grounds they produce a louder, raucous multisyllabic call, commonly in early evening.

Rafting coots, Lake Maxinkuckee

Rafting coots, Lake Maxinkuckee

29NO86. Culver. Coots didn’t steal from canvasbacks, but they weren’t diving, either. They followed the cans around, occasionally reaching for dropped scraps of aquatic plants.

7MR87. Coots have arrived at McKee Marsh, Blackwell Forest Preserve.

27FE00. One seen at McKee Marsh.

Coot on Deep Quarry Lake, West Branch Forest Preserve

Coot on Deep Quarry Lake, West Branch Forest Preserve

12MR00. Several at McKee Marsh.

9NO01. A flock of perhaps 100 coots on Red Rock Lake in Iowa, just above the dam, was in an odd-looking, very tight group with none diving. They stayed that way, appearing to touch or nearly so, for the greater part of an hour. Bald eagles were in the area and may have inspired this unusual formation. It looked especially odd since the lake is very large, and they were far from shore with no other birds on the water nearby.

Coot and gadwall in a Nevada marsh

Coot and gadwall in a Nevada marsh

11NO01. Large numbers of coots were on the Mississippi River and flooded areas beside it, just north of Lock and Dam 13.

20OC02. Many coots have been on Maxinkuckee for weeks. This morning, 2 engaged in an agonistic encounter well off shore, paddling with their feet so as to lift the front parts of their bodies high out of the water, perhaps 60 degrees, facing one another, lifting heads on extended necks in an apparent effort to get beaks above the other, close together, uttering rapid high-pitched clucks.

Coots, Maxinkuckee

Coots, Maxinkuckee

27NO10. Coots had been feeding near shore all afternoon, but as dusk deepened they all moved far off shore.

Lessons from Travels: Adak Eagles

by Carl Strang

One side study in my Ph.D. thesis work with glaucous gulls in Alaska was an exploration of apparent hybridization with another gull species. I’ll get into that another time. For now, the point is that it gave me the opportunity to spend some time on Adak Island in the middle of the Aleutian chain, where I studied glaucous-winged gulls. I was hosted by the naval base there, which was a legacy of WWII. One of the unusual sights in early spring on Adak was a concentration of bald eagles.

In summer the eagles scattered around the Adak coast, but in winter they congregated at the naval base.

What drew them? The dump.

Here an immature eagle picks at a bit of garbage.

At the time, bald eagles in most of the continent still were at a low point thanks to metabolites of DDT which interfered with eggshell production, and so it was truly novel to see so many in one place. Now that the eagles have recovered, we find concentrations of them along rivers in Illinois in winter, where they feed mainly on fish. The ones on Adak were not exclusively garbage-eaters, however. One day I watched a young eagle as it flushed a flock of roosting gulls (likewise concentrated by the dump), chasing one down in mid-air and killing it.

It brought its prey to shore, where it was joined by an adult.

The adult chased the youngster off its catch, and ate the gull. As I will elaborate tomorrow, the naval base since has closed, and the eagles no doubt are making do without those easy winter pickings.

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.

Literature Review: Food Web Stability

by Carl Strang

Though my annual scientific literature review focuses on the current year’s publications, sometimes I have to backtrack because I learn of a significant paper I missed in a previous year. My most recent time in the Northern Illinois University library included the search for such a reference. I learned of it through a review or news article in Science, which I count on to keep me informed about significant papers in the journal Nature. I don’t have the time to follow both.

Neutel, Anje-Margriet, et al. 2007. Reconciling complexity with stability in naturally assembling food webs. Nature 449: 599-602.

Random models of communities predict that complexity will lead to instability. If such models were correct, there would be fewer species in wild communities than we observe. This study looked at soil communities in which increasing primary productivity correlated with increasing biodiversity. Critical to stability were interactions involving omnivores and diet switching. If a significant predator became too abundant, threatening food web stability, its numbers were reduced when its own predators switched their diet to concentrate on it. An example involved bacteria, a bacteria-feeding nematode, and another nematode that could feed on either of the others.

Diet switching is a common behavior in animals. Gulls, like the glaucous gulls in the photo, have a very broad diet. In my graduate study of these birds in Alaska, I found them flexibly switching among such diverse foods as fish, marine invertebrates, small rodents, bird eggs, young birds, carrion and berries as these different foods became available in different seasons and different places. Gulls have predators of their own, as I observed on Adak Island.

The young eagle caught the glaucous-winged gull in flight, but shortly after I took the photo the youngster was rewarded for its effort by the adult eagle driving it away from its catch. Neutel et al. point to diet switching as a mechanism for maintaining biodiversity. I also have seen an example of what happens when systems lack such switching. In earlier posts I have described my study of the trailing strawberry bush and ermine moth at Meacham Grove Forest Preserve. 

The ermine moth caterpillars have only one food, the trailing strawberry bush, in this forest, and apparently their own specialist parasites lag behind them. There is no capacity for switching, and the result has been boom-and-bust population dynamics.

Spring Bird Count

by Carl Strang

Saturday was the Spring Bird Count in DuPage County. I explained the principle in my description of last December’s Christmas Count . I have less to show you on the spring count. The area was much the same, and again was led by Urs Geiser. There were enough of us to split into two subgroups. I was joined in my subgroup by Michael Marlow and Bruce Struckman. We covered Kline Creek Farm and the nearby North Woods subdivision, a beautifully wooded area surrounded on all sides by forest preserves. The only bird photo I managed to get was of our first scarlet tanager.

Scarlet tanager b

Other highlights were a vesper sparrow, a bald eagle, and three golden-winged warblers, plus a variety of other beautiful birds briefly glimpsed or heard through the dense vegetation in the gusting winds that impaired us that day.

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