Rose-breasted Grosbeak Species Dossier

by Carl Strang

As usual, the dossier begins with the paragraph that established the file in the mid-1980’s. In this case I didn’t have much to say because my experience with the species was limited. Since then, dated notes have appended observations that I felt added to my understanding of the species.

Grosbeak, Rose-breasted

This species was relatively rare around my home town of Culver, Indiana. My first were a pair in my neighborhood in the town. The male sang from high in trees or TV aerials. His song began with a phrase much like the theme of the “Guestward Ho” TV series which was current then. That mnemonic has helped me recognize it elsewhere in Indiana as well as Pennsylvania and Illinois. They also have a loud “pick” call distinctive in quality from their close relative the cardinal. Foraging movements are slow, taking their time while visually searching for insects at mid to high elevations in trees. They are uncommon during the breeding season (though abundant in migration) in DuPage County, with occasional single pairs here and there in savannah-like forests. They are especially common for a couple of weeks during migration in May.

Adult male rose-breasted grosbeak

Adult male rose-breasted grosbeak

5MY87. First song of the year heard at Willowbrook Forest Preserve.

25JL87. Hartz Lake, Indiana: An adult male fed 10-15 feet up in saplings. Deliberate: about 10 seconds per perch, looking apparently over a radius of several feet, moving 2-5 feet between perches.

A male reaches for a food item. They can look very parrot-like in this maneuver.

A male reaches for a food item. They can look very parrot-like in this maneuver.

13SE87. A female was in a mixed flock with a red-eyed vireo, a Tennessee warbler, and several catbirds and robins.

7MY88. First song of the year, Culver, Indiana.

11MY88. A female was in Willowbrook Forest Preserve.

8MY89. I saw grosbeaks today and on May 6th at Willowbrook.

Singing posture

Singing posture

4MY99. First migrant noted at Willowbrook. Last observed there 14MY.

26AU99. First migrant noted at Willowbrook. Last one noted 29SE.

4SE99. A grosbeak in female plumage at Willowbrook produced “pick!” notes and bits of low-volume warbling song.

11JE00. Rose-breasted grosbeaks were in a diverse forest near Langlade, Wisconsin, associated with the Wolf River riparian edge and with savanna-like areas where trees were more scattered. Deciduous trees were abundant in those areas. Other birds in those habitats were least flycatcher, Baltimore oriole and black-throated blue warbler.

23-4SE00. Grosbeaks were numerous along the Prairie Path just east of Industrial Drive and bordering the West Chicago Prairie, in the hedge-like edges.

21MY08. Fullersburg Woods. A rose-breasted grosbeak nest was on Willow Island, midway along the east side. It was 10 feet up in the top of a buckthorn, 15 feet in from the trail, female incubating. The nest structure resembles that of the cardinal but thinner so you can see through it in places.

Literature Review: The Aleut Story

by Carl Strang

As mentioned in yesterday’s post, I got to spend some time in the Aleutian Islands as a graduate student. I heard a few things about the Aleut people at the time, but a news review in Science last year provided the opportunity to learn more about this interesting chapter in the human story of our continent.

Balter, Michael. 2012. The peopling of the Aleutians. Science 335:158-161. This article reviewed recent and current research into Aleut archeology. Archeologists have found that the Aleuts spread into the islands from the Alaska Peninsula rather than from Siberia, and they did so in two waves. The Paleo-Aleuts had skeletal features with some European influence, a simpler social structure (for instance, houses had only one room), and a simpler economy (they ate mainly fish, seabirds and sea otters). They reached Adak Island in the middle of the chain by 7000 years ago (glacial remnants made living in the Aleutians impossible until 9000 years ago), and the western islands around 3500 years ago.

The Aleutian Islands have some dramatic scenery.

The Neo-Aleuts began to arrive 1000 years ago, and blended with rather than replaced the Paleo-Aleuts, with today’s people showing a ratio of about 2/3 to 1/3 Neo-Aleut to Paleo-Aleut genetics. The Neo-Aleuts brought innovations of multi-room houses, and preyed on larger sea mammals including seals, sea lions and Steller’s sea cows. The population was estimated at 16,000 in 1740, but Russian enslavement for fur harvesting knocked them down to about 1600. They increased after American acquisition of Alaska, but were removed from the Aleutians during WWII as it appeared that the war would endanger them. The naval base on Adak closed in the late 1990’s, some Aleuts have moved back there and to other islands in the chain, and culturally they have conserved some of the distinctions of different island populations despite the mixing imposed by the Russians.

The returning people found a mix of resources and wreckage left behind from the military chapter of Aleutian history.

Aleuts are closer to Siberians than to Yupiks (the nearest “Eskimos”) genetically, apparently having crossed the Bering Sea independently and remaining culturally distinct through their spread into the Aleutians. Though their facility with sea travel has been cited by some as evidence for a coastal spread southward of Native Americans in glacial times, others point out that the Aleuts came along much later.

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.

Grama and Onions

by Carl Strang

This week’s addition to the winter botany gallery is of two quite different plants. The first is a dry-soil grass, the side-oats grama.

The fruiting head is distinctive, as was the grass when blooming.

When I think of this plant’s flowers, I remember the brilliant red of its stamens.

I need to get a better photo. This one was just starting to bloom, and only gave a hint of that striking color.

Here is the other plant I want to feature today.

It has a more or less spherical head, and black seeds.

I knew that these plants had to be onions when I noticed them last week, but Mayslake has two fairly common species, the wild onion and the nodding wild onion. Most of these were not obviously nodding, though they did appear to have a slight flex in the top part of the stem.

Others clearly were nodding.

When I went back to check references, I learned that all the ones I had seen were nodding wild onions. The other species does not have nearly so many flowers. Apparently these often straighten up after blooming.

Here is a nodding wild onion flowering.

I did not notice any wild onions in fruit. That is one of the species for which I will need to note exact locations if I am to know what they look like (or whether any parts of them remain visible) in winter.

Skunk at Mid-day

by Carl Strang

Twice in November, when my noontime walk has taken me into the former friary site at Mayslake Forest Preserve, I have seen a striped skunk out and about. The first time it was close to a known den hole, and the sighting was a novelty. Occasionally I have encountered other nocturnal mammals, including raccoons and opossums, out in the middle of the day over the years, and though I had not seen a skunk doing so, it’s also true that skunks are less common than those other animals. But then I saw the skunk the second time.

At first the skunk looked normal enough.

It was moving in the usual gait at the usual speed, apparently stopping frequently to pause, dig a little, apparently eat an insect, and continue. But then at one point it stopped and lifted its head, turning it in various directions and sniffing. The eyes looked strange.

Was it simply squinting in the unaccustomed light?

Another possibility is that the animal is blind. This likewise would not be unprecedented. When I worked at the Forest Preserve District of DuPage County’s Willowbrook Wildlife Center, I knew of several opossums that had been brought into the clinic over the years, opossums that had been congenitally blind. They were healthy otherwise, and had functioned well enough to achieve adulthood, but had wandered into places where they got into trouble. They could not be released, however, into an unfamiliar area, and so were kept on as exhibit animals.

Skunks, likewise nocturnal, also live largely by their noses. If this one is blind indeed, it seems to be staying in a part of the preserve where it will be able to maintain itself without negative encounters with dogs or people. There is no point in trying to trap it and take it to Willowbrook. The Wildlife Center’s permit from the state requires its staff to euthanize any skunks or bats that come in, because they are the animals most likely to have rabies. I will be interested in following this skunk’s career. After all, it may not be blind at all, just odd.

Two Winter Grasses

by Carl Strang

This week’s winter botany focus is on two more grasses. This time the species look quite different, so as to emphasize the diversity of winter plant appearance.

Little bluestem has reddish stems that form well defined tufts, standing out from their surroundings.

Up close, the fruiting structures are complex and beautiful.

The seed strands have a delicate, feathery structure.

Little bluestem is a native grass of dry to mesic prairies. The next species, orchard grass, is an Old World import that prefers somewhat shaded areas.

Its denser clusters of seed-bearing structures have a relatively heavy, solid look.

The yellow-brown color of orchard grass in winter is more typical of grasses generally. When blooming, orchard grass likewise shows a clumped floral structure.

Orchard grass in the summer is tinged blue-green.

Orchard grass has some visual interest, but if I had sunny space to fill in a landscape plan, little bluestem would be my choice.

Literature Review: Earliest Animal Life

by Carl Strang

Yesterday’s post featured reef communities of today and the distant past. Today I want to stay in those early times when multicellular animals first entered the fossil record. The first paper was published about a year ago in Science.

Erwin, Douglas H., et al. 2011. The Cambrian conundrum: early divergence and later ecological success in the early history of animals. Science 334:1091-1097.

They used a variety of improved molecular clock, fossil, developmental and ecological data to look at animal diversification which seemed to appear full blown in the Cambrian Period at the beginning of the Paleozoic Era. They concluded “that the major animal clades diverged many tens of millions of years before their first appearance in the fossil record,” with basic developmental toolkits appearing in the Cryogenian Period of the Proterozoic Eon (before that eon’s final, Ediacaran Period). The researchers place the split between sponges and other animals in the mid-Cryogenian about 750 million years ago (mya), with Cnidaria (the group that today includes corals, sea anemones and jellyfish) appearing around 700mya, Chordates around the beginning of the Ediacaran, arthropods around the beginning of the Cambrian, and vertebrates in the late Cambrian. Only some of the well-known fossil Ediacaran organisms can be tentatively tied to the animals of today: some possible sponges, mollusks and placozoa. Otherwise, there are only some suggestive trace fossils (e.g., burrows) from the Ediacaran Period that point to metazoan animals. Erwin’s group attributes the apparent “Cambrian explosion” to the evolution of predation, which applied selective pressure resulting in protective shells and other structures that were better preserved in the fossil record.

Barnacles, arthropods that protect themselves with shells.

Another paper, published earlier this year, added another dimension to the story.

Shanan E. Peters, Robert R. Gaines. Formation of the ‘Great Unconformity’ as a trigger for the Cambrian explosion. Nature, 2012; 484 (7394): 363 DOI: 10.1038/nature10969

As reported in a ScienceDaily article. This study focused on the largest gap in the geologic record worldwide, dividing the Proterozoic Eon from the Cambrian Period which opened the Paleozoic Era, and tied that unconformity to a hypothesis about the sudden appearance of diverse life forms and skeletal features. They suggest that the erosion of preCambrian rock that produced the unconformity had the effect of adding concentrations of dissolved minerals to the sea. The resulting altered chemistry of their environment posed a challenge to living forms. The first production of biominerals thus was to remove those substances from organisms’ tissues. Having evolved that capability, animals then had the foundation for evolution of various uses of those minerals in shells and other skeletal formations, teeth, etc.

Thus the geological processes that grew the early continents, and lifted them above the sea, altered the chemistry of that sea. There were no land plants to resist the erosion. The marine animals, in addressing the challenge posed by the increased mineral content, found ways to create hard parts which in some were useful tools for predation, and in others were armor to resist that predation. The visible result of this biological arms race was the “Cambrian explosion,” in which multicellular life forms suddenly began to appear as fossils. But now evidence exists that points to those animals’ ancestors having diversified much much earlier.

Lessons from Travels: Reefs

by Carl Strang

One of the most breathtaking experiences is that of tropical coral reefs. Whether you explore them by snorkeling, as I have done a few times, or take the plunge and scuba dive, the beauty of reef communities is so far removed from our everyday experience that it safely can be described as “out of this world.”

The shapes and colors of the corals and other fixed life forms are sufficient to satisfy the aesthetic need. But then add the diverse, colorful fishes and other freely moving animals, and the experience is transporting.

Beaches near reefs may be filled with the rubble from eroded coral formations, as well as mollusk shells and other remains of ocean life.

The pieces are reminiscent of fossils.

This brings us back home. Our bedrock in northeast Illinois and northwest Indiana is Paleozoic in age. It formed when our part of the world was a shallow sea, and was in fact punctuated by reef communities. There were corals, though they were not the ancestors of today’s corals. For most of that time fishes were absent or few. I think, though, that snorkeling or diving in those reefs would have been just as transfixing as today’s experience. The trilobites and other animals were diverse and active, some swam, and they well may have been as colorful and patterned as the reef animals of today.

Winter is edging in, and so we enter the season when tropical reefs seem most remote in time and space. One brief respite can be found in the prehistoric life exhibit at Chicago’s Field Museum of Natural History. There is an enormous animated wall that shows what a Cambrian reef might have been like, with the fixed forms, the slowly moving ones, the fast swimmers, the episodes of predation, all with a very relaxing background sound. I cannot visit that museum without spending a few minutes enjoying that scene. Sometimes lessons don’t need distant travel.

Ridge Trim “Mohawk”

by Carl Strang

As I tell the story of Mayslake Forest Preserve, from time to time I have to insert a focus on the outstanding effort by the volunteer restoration team. Led by stewards Conrad Fialkowski and Jacqui Gleason, this group is largely responsible for the high quality plant communities on the preserve, their maintenance and their enlargement. One of this year’s foci has been the south end of the savanna ridge, above the east end of May’s Lake. Long covered by an understory of dense buckthorn, in recent years the ridge gradually has been exposed through the patient techniques Conrad has tested over the years. The end is drawing near.

The many brush piles and the cleared ground attest to the volume of intense physical labor put in by these dedicated people in recent months.

Only a topknot stand of buckthorn remains at the peak of the ridge’s south end.

The remaining buckthorn in the background stands above soil as bare as in the cleared foreground. The cleared area will be seeded with bottlebrush grass, beginning to establish the native vegetation that will claim the space beneath the oaks.

Clearing is only part of the work, as the team gathers tens of pounds of seed from the preserve’s native plants, which they then spread in the opened areas. This effort cannot be praised enough.

Beaver Species Dossier

by Carl Strang

The species dossier idea came from my realization in the 1980’s that much of what I “knew” about wildlife came from the scientific and popular literature rather than personal experience. I went species by species, writing what I could remember about each one from memories of my own observations. Then I built the dossiers with added notes. The dossier begins with the initial paragraphs, followed by notes dated by a code that uses two-letter combinations to signify months.


Beaver, Salt Creek at Fullersburg Woods

This aquatic rodent lives in ditches, rivers, and lakes. Observations to date have been in the Culver, Indiana, area (Maxinkuckee, Tippecanoe, Yellow River, Fish Hatchery), southern Ontario, and DuPage County, Illinois. The signs are seen much more often than the animals themselves; they are crepuscular/nocturnal for the most part, although the Canadian ones occasionally appeared in daytime, and I have seen them during the day in northern Lake Michigan and the West Branch of the DuPage River (mid-winter). Alarm signal: dives noisily, augmenting the splash with its flat tail.

Stand-alone lodge, Canada

They feed on bark and twigs of willow and other woody plants, storing large underwater piles of branches in fall for winter use. They also stripped bark from the 1-4″ diameter X 1-3′ long sticks used in building dams and lodges. The den can be in a bank or in a stand-alone built lodge. Bank dens are used in larger, deeper rivers and lakes, although built lodges also can be seen in such places. I have seen built lodges in Canada, Lake Maxinkuckee (Venetian Village), DuPage Co. (e.g., Churchill F.P.), Isle Royale. They have a distinctive appearance because of the white sticks, though some lodges on riverbanks are not rounded and so at first glance resemble piles of drift from the last flood. Mud also is used in construction. Lodges have been 8-15′ in diameter, 2-4′ high, usually on a bank.

Beaver dam, Tri-County State Park

Small streams may be dammed to create a pool (the most ambitious dam I’ve seen was on the West Branch of the DuPage River at Blackwell in mid-winter). Dams, like lodge coverings, are built of stripped sticks, mud, vegetation, usually have a slight U-shaped bend pointing downstream, and are not particularly high above the contained water level, though some on Isle Royale were taller than me on the downstream side. Very long dams can have a more sinuous shape; I’ve seen them more than 50′ long.

High beaver dam with trail, Canada

Beavers will carry branches from other bodies of water to the home pool. Cut trees are distinctive with large tooth marks and pointed (cone-shaped) ends. Beaver tracks are large, and have the rodent formula (4 toes front, 5 back), the webs of the hind feet not always making noticeable marks.

Beaver front footprint

31AU86. Beavers at Culver’s fish hatchery have reinforced the base of their dam with a heavy plastering of marl.

18DE86. Month-old beaver sign, Willowbrook Back 40: several black cherry trees had their bark chewed off on the stream side of the trunk. No others in the vicinity (willow, box elder) were damaged.

11JA87. At the mouth of Sawmill Creek, Waterfall Glen F.P., beavers this morning fed on bark of a box elder 7″ dbh, they had cut down earlier. They had made a trenchlike single path in 6″ snow between stream and trunk.

8MR87. 2 ash trees 8″dbh cut down but only some bark removed from trunk. Otherwise untouched, for months.

Beaver-felled tree, Fullersburg

28MR87. Beavers at Waterfall Glen cut three 8″ dbh bur oaks, ate much of the bark from 2 of them, in an area with much willow.

23JA88. McDowell F.P. Beavers built a long winding dam on Ferry Creek, 20-30 yards long

15MR90. McDowell. Beavers were active in the evening dark during my night hike program. We heard one chewing: identical to the sound of a squirrel gnawing a nut, and as rapid, but much louder. Several of us shined lights on it. It was on the opposite side of the river, standing up on its hind feet, against the tree. After at least 30 seconds of being illuminated, it abruptly ran into the river. It swam for another 20-30 seconds, still in lights, then walked up the bank back to the same tree, and resumed gnawing. The alarm splash is like a big rock being thrown in. I didn’t detect a tail slapping component.

13NO99. A beaver dam has been built across the very low West Branch of the DuPage River, Elsen’s Hill at the eastern horse ford.

29MR00. While running past the borrow pit at McDowell Grove Forest Preserve, I frightened a beaver into the water. It swam under the surface for 20 feet or so, a stream of bubbles revealing its position, then surfaced. Immediately it dove again, but as it did so I saw it deliberately lift its tail and slap it on the water. I could detect the sound of it, but the splash made by the posterior part of the body (spread feet?) was the louder sound. Perhaps the double sound makes it a communication for beavers, to distinguish it from other splashes.

11MR01. A beaver lodge is on the shore of the old gravel pit on Timber Ridge Forest Preserve (at the intersection of County Farm and Geneva Roads). There has been much recent gnawing of nearby woody plants.

8AP01. At around 8:30 a.m. at Red Oak Nature Center I heard a gnawing sound down near the edge of the Fox River. It was a beaver, sitting in the shallow water and feeding on the twigs of a shrub or small tree overhanging the river (intervening brush too thick to get an ID of the plant). The beaver was reaching up, biting off a branch, then consuming the twig. Less than about 3/16″ in diameter, the twig was consumed by the beaver holding it like a piece of stick candy and nibbling on it with gnawing sounds reminiscent of a squirrel working on a nut but more rapid. After 2-3 seconds of biting off the end, the beaver chewed with its molars for a few seconds, swallowed, then worked on the end some more. When the diameter of the remaining twig became greater, approaching 1/4″, the beaver turned it sideways (always holding it in the front feet) and quickly stripped off the bark.

22OC01. Beavers have been very busy in recent days at the marsh beside South Blackwell’s Heron Trail (marsh full of water thanks to heavy rains in recent weeks). They have trampled a path through the cattails all the way to Heron Trail, and have been cutting the small willows and cottonwoods into pieces, eating the bark from some of the bigger chunks, and hauling the tops into the water (drag marks visible in the mud).

6JL07. Fullersburg. A beaver swimming up the main channel along Sycamore Peninsula went to the shore at 8:30 a.m. and ate some root bark and twig bark from American elms. It continued upstream past the Visitor Center.

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