One More For the List

by Carl Strang

One product of my continuing natural history survey at Mayslake Forest Preserve is a set of species lists. As of the start of this year, I had observed 14 species of mammals or signs of their presence on the preserve. In addition, there is evidence of past activity by beavers, in the form of old beaver-cut trees.

No beavers are presently on the preserve, however. When I moved my office to Mayslake in late 2008, it was past the time when woodchucks would have entered hibernation. I fully expected to find them on the preserve. The habitat looked right. However, I have yet to see one or any tracks there. The closest woodchuck I have seen to Mayslake is one that is active along the edge of 31st Street a quarter mile or so to the west.

On one of my recent lunchtime walks I found an old skull fragment in the prairie just north of the stream corridor marsh.

The skull’s size, the arrangement of the molar tooth root holes, and the flattened or slightly depressed top of the head all point to a single identification: woodchuck. So, they have been at Mayslake, and could well appear again, but for now I have to include the species on the preserve list as a past presence only.

I close with a koan: Groundhog or ground hog? Woodchuck or would Chuck?

Fox and Gray Squirrel Habitats

by Carl Strang

There are two species of tree squirrels in my county, the gray squirrel and the fox squirrel. Both occur at Mayslake Forest Preserve. The gray squirrel is regarded as a forest species, living in woodlands where the canopy is closed. It is a little smaller than the fox squirrel, and its fur has dominantly white and gray tones, as modeled by the Phantom of the Mansion.

Fox squirrels are regarded as a savanna species, living where the canopy is more open. With their greater exposure to weather extremes, and their greater need to forage on the ground (where they are exposed to more predators), fox squirrels have evolved a larger body size. They have fur tones that are more orange, especially in the tail and undersides.

This is the conventional understanding, but scientific ideas always are open to repeated testing. I was interested in looking at the squirrels’ habitat preferences at Mayslake, and so for an entire year that ended March 19 I noted the habitat where I observed each squirrel. The Forest Preserve District of DuPage County has all its preserves mapped out into habitat blocks, so it was easy to record and summarize the data. Seven of the preserve’s 15 habitat blocks are open wetlands, prairies and meadows. I counted no squirrels in any of these. Four habitat blocks totaling 21.4 acres qualify as forest, though I should mention that these are low quality, with a dense invasive shrubby understory. Over the year I counted 92 fox squirrel and 24 gray squirrel observations in these areas. The remaining 4 habitat blocks are better quality savanna, and cover 34.8 acres. The counts there were 414 fox and 64 gray squirrels.

A first approach, which does not require consideration of the different sizes of the forest and savanna habitats, is to look at ratios of species counts: 3.8 fox to gray in forest, 6.6 fox to gray in savanna. Though both species are using both habitats, fox squirrels are more dominant in their expected savanna habitat.

Further data interpretation needs to take into account the different habitat sizes. In the savanna I saw an overall 11.9 fox squirrel observations per acre, and 1.8 grays. In the forest the respective numbers were 4.3 and 1.1. If we just look at these numbers, it appears that fox squirrels are dominant in both habitats, and both species prefer the savanna. This is reasonable, given the low quality of the forest blocks. However, I felt it necessary to conduct statistical tests, especially given the relatively small difference between the numbers of grays in the two habitats. For those interested in the technical details, I used chi-squared tests with one degree of freedom based on the full squirrel counts, with expectations based on the relative sizes of the respective habitats. As always is my preference, I chose a 1% error level. Chi-squared values were 85.5 for the fox squirrel, more than enough to indicate statistical significance, but only 4.79 for the gray squirrel, so no habitat preference is indicated for that species.

Mayslake’s history, and recent restoration work, clearly have favored fox squirrels. Over time the “forest” areas, which in fact are pretty trashy ecologically, will be converted to savanna and open habitats. As that happens, future counts of squirrels may reveal what impact, if any, the change has on Mayslake’s two squirrel species.

Winter Campfire 20

by Carl Strang

Winter is a time when we slow down and become introspective. Sitting and staring into the fire, we ponder the big questions. If you have been following this blog, you know that the focus here is science, science that can be done simply in outdoor settings. But we are more than scientists, and science has well defined limitations that need to be understood by everyone who does science or studies its findings. This winter I am using one post per week to develop my own viewpoint and biases, in particular sharing my take on the relationship between science and spirituality. In part this defines for me what these two realms of human experience are all about, and also develops the separate methods used for inquiry in each realm. I plan to place this paragraph in front of each entry in this series, so that those who are interested only in natural history or in scientific practice can skip these posts.

The Eternal Tapestry

It may not be possible for our thoughts and visualizations to go beyond the limits imposed by our experience in space, time, and Umwelt. This is what we would need to do, however, if we were to view this world from God’s eternal perspective, encompassing every thing and all times at once. What would one of us look like from that perspective, which is consistent with relativity’s block-space-time? A worm, twisting through space-time, with one end at birth and the other at death? That’s just the part of ourselves projected into this world, though. And it’s a visual image, a physical-sensory one, defined and thereby limited by physical laws that are themselves limited by space and time. (Also, not a particularly pleasant comparison if you’re not a worm).

Nevertheless, this is where we must start, and it’s worthwhile, even if all that is accomplished is to point out the weakness of our grasp of ultimate reality. All of us space-time worms (and I include all things here, not just human beings) together might seem, from an Eternal (all-times-at-once) perspective, to be the threads of a tapestry. These threads (there, we’ve left that worm image behind; a more correct term from physics would be world-tubes) come together at “moments” when we are together with the threads of other people and things in particular places. Intuition and synchronicity imply that the tapestry is folded, bringing bits of the threads into proximity to one another at various “moments.”

Proximity to one’s own thread in the “future,” for instance, could represent a premonition. The first time I ran Section 4 of Wisconsin’s Wolf River in my kayak, the water level was fairly high, at 17 inches on the standard gauge. We came to the final drop, the intimidating Big Smoky Falls. One of the more experienced members of our group nearly flipped halfway down, but caught himself with a heroic brace. I had the opportunity to carry around the rapid, but I was inspired to reach out emotionally, and I got a feeling of myself having completed the run safely. No doubt it was beginner’s luck, but I hit the line perfectly, and went home with the exact feeling of relaxed contentment I had touched just before the run. Often, since then, I have been able to anticipate the positive outcome of various ventures, but can’t always make such contact with my future self (if that’s what is happening) when I try.

One reason I want to explore this Eternal perspective is to develop ideas on such things as our purpose in life, predestination, fate, etc. It’s easy to get the impression that, because those threads are complete from an Eternal perspective, all choice is taken away from us. But I don’t think that’s the case. Our experience of separateness and of time makes free will possible, expressed in the decisions we make in the moments of “time.” That allows us to be self-shaped entities while also being timeless and eternal. Thus the thread that represents me is self-weaving, creating its own route, its own shape in space-time. I experience the moments of decision, in my every day life, which create that shape. God-as-a-whole may not experience sequence, but we do. Incidentally, it seems to me that a person must be a different thing entirely when regarded from an eternal perspective. Our thoughts, images, experiences and emotions in each moment don’t cease to exist, but they must somehow all be there at once. Any concept of God-as-person needs to include this difficult perspective.

This image of a tapestry, composed of threads that represent the interwoven courses of our lives and unified to form a single body, resolves for me a question that I think has gotten inadequate attention. That is the tension between the mystical intuition of the oneness of all things, on the one hand, and the apparent division of the universe into the particularized 10,000 things (Rumi: “How can I be separated and yet in union?”). The tapestry reveals the connections between particularization and time, on the one hand, and between oneness and eternity, on the other. Each thread creates its shape as it winds through time, constrained by and interacting with the threads (simultaneously creating themselves) around it (note the parallel to the fractional dimensions of chaos theory). Collectively the threads are revealed as forming an eternal, singular tapestry of oneness.

I like the image of the tapestry, but I don’t want to be too attached to a single, limiting model. Another relevant idea that, however, requires us to bring time back in, is an analogy between the physicists’ momentary virtual particles popping in and out of the energy vacuum, on the one hand, and our emerging into the physical universe to be viewpoints of God and popping back out, on the other. I’m reminded of reported “near death” experiences of one’s entire life reviewed in a flash, which might be regarded as momentarily merging with eternity.

Literature Review: Short-tailed Shrew Venom

by Carl Strang

In an earlier post  I mentioned the salivary poisons of short-tailed shrews. A paper published last year reported an analysis of the venom.

Harvard University (2009, November 2). Venomous Shrew And Lizard: Harmless Digestive Enzyme Evolved Twice Into Dangerous Toxin In Two Unrelated Species. ScienceDaily. Retrieved November 3, 2009, from­ /releases/2009/10/091029125532.htm

The paper’s authors, Yael T. Aminetzach, Hopi E. Hoekstra, John Srouji, and Chung Yin Kong, published in Current Biology. They found that the short-tailed shrew’s venom is a derivative of a digestive enzyme (kallikrein). The version produced in the salivary glands is more active, making it poisonous. The Mexican beaded lizard’s bite venom is a different variant of the same digestive enzyme, having evolved independently.

The science of evo-devo  has produced concepts that shed light on these results. Every cell in the shrew’s body contains the same genes, including that for producing kallikrein. At some point in the past, apparently the very distant past, the common ancestor of shrew and lizard (and us!) used this gene only for digestion. The steps to today include the production of a modified version of the enzyme, the increased toxicity of the modified version, and its production by the salivary glands. These steps happened twice, in the two distantly related species.

In the earlier post I mentioned that the shrew’s poison renders it distasteful to predators. I had thought that there were levels of the poison in the shrew’s tissues, but now I wonder if they simply are applied to the shrew’s fur when it grooms itself.

Three Easy Winter Plants

by Carl Strang

One reason to appreciate plants in winter is to expand one’s ability to identify them in any stage and season. Some are easier than others to identify, and today I will focus on three that are both common and distinctive. The most widely distributed of these, Queen Anne’s lace, is not native to North America.

It has the appearance of an umbrella’s ribs from which the fabric has been torn. You may find it open, as above, or closed.

When flowering, these heads likewise have two forms. In some cases there is a purple flower in the center,

and in some, that flower is missing.

Numerous experiments have failed to demonstrate a difference in seed set between the two. Today’s second species is the common evening primrose. Its flowers in late summer were pale yellow.

In winter, the appearance is distinctive even at a distance.

Up close, the stalk is topped with a cluster of vase-shaped pods distinctively spreading at the tips.

Yet a third unmistakable shape is the spherical seed head of the wild bergamot.

The seed head is composed of tiny tubes radiating in every direction. Step back a little and the plant still is unique in appearance.

This species has become so successful in prairie and savanna restoration projects, spreads so readily, and also has become popular in garden plantings, that finding them in winter is no challenge. Here is one reason for its popularity.

Soon we’ll have green plants again to enjoy.

Spring Comes to Mayslake

by Carl Strang

Yesterday I looked back at late winter on Mayslake Forest Preserve. Today I want to share some early signs of spring. There still was a patch of ice on May’s Lake when the first migrant ducks, some lesser scaup, stopped by.

Flocks of sandhill cranes have been passing over on the nicer days.

We also have seen the first flowers of the season already, on silver maples.

Garlic mustard seedlings have germinated.

Soon I’ll resume my experiments on controlling this problem species. Other recent spring events have been chorus frogs singing, the first active chipmunks, red-bellied woodpeckers calling near where they nested last year, and the appearance of insects that overwintered as adults, including a box elder bug and a mourning cloak butterfly.

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.

Winter Campfire 19

by Carl Strang

Winter is a time when we slow down and become introspective. Sitting and staring into the fire, we ponder the big questions. If you have been following this blog, you know that the focus here is science, science that can be done simply in outdoor settings. But we are more than scientists, and science has well defined limitations that need to be understood by everyone who does science or studies its findings. This winter I am using one post per week to develop my own viewpoint and biases, in particular sharing my take on the relationship between science and spirituality. In part this defines for me what these two realms of human experience are all about, and also develops the separate methods used for inquiry in each realm. I plan to place this paragraph in front of each entry in this series, so that those who are interested only in natural history or in scientific practice can skip these posts.

Love and Beauty      

It’s time to bring love into the discussion. What is love, after all? I don’t think love is any single thing. I believe that it is, in part, the spiritual essence or substance of which God, the Universe, and we are made, and it flows through all, tying us all together. Love also is a feeling, a sense. We feel love most strongly when using our senses purely, thereby perceiving the beauty and feeling our fond connection with whatever it is we are sensing. When we forget our concepts, drop our judgments, fail to recognize and therefore get a fresh impression of something, we open ourselves to a jolt of that love flowing through, and the subject of that perception is the conduit, so we associate the feeling with that object. This is the purest spiritual experience I have known or heard of. Even the Void encounters don’t touch it, but the Void is a step beyond spirit, anyway. In short, love is both the metaphysical “substance” that composes and connects together all that is, and the feelings of fond connection we experience when perceiving that essence. Those feelings are strongest when we use the senses purely, but even the more mundane, everyday, selfish loves we experience (I love hot fudge sundaes) touch that flow to some degree and therefore qualify to be called “love.”

A few more words are in order specifically directed toward the notion of beauty. Here my ideas have been informed by James Kirwin, whose 1999 book Beauty gives a thorough philosophical review of the subject, and by Thomas Merton, through a 1988 lecture entitled “Beauty is from God.” I find that my thoughts also echo two booklets published by the Theosophical Society: The Yoga of Beauty (1976) by Laurence J. Bendit, and Truth, Beauty and Goodness (1985) by Radha Burnier. We say that an object (image, sound, etc.) is beautiful, but beauty is better regarded as an experience of the person perceiving the object. I believe that beauty is a profoundly spiritual experience in which, for an eternal moment, we are absorbed in a spiritual connection or unity with the object. In that moment we perceive intuitively the spiritual goodness or essence, the love, within the object. But that connection is expressed in part through the feeling of beauty. Thus beauty is a connection to God, more direct when we perceive it in wild things, a step removed when we perceive it in a work of art. Being extensions of God, we share in the creative capacity, expressing it through our own artistic creations. Beauty is different from the feeling of love mainly in that beauty is projected onto the object, is a way of our regarding the object. Though we are connected to it, we regard it as being outside ourselves. Love is more the felt connection between us and the object, with less of a division between the two. And wonder is a related feeling, akin to beauty but having an element of mystery. There is surprise, the dawning realization that here is something not yet encountered, not yet known or understood.

Since all is God, all should be beautiful. Therefore a measure of a person’s spiritual consciousness could be, how much of the world he/she can perceive as beautiful. The easy, obvious perceptions of beauty represent an initial spiritual call, which anyone has the ability to hear. At some midpoint are the beauties experienced through sensing things purely. These first two categories contain responses to those things people did not create, as well as human creations that emerged from artists connected with and expressing Spirit. (Beauty in the context of art criticism is a complex subject, ranging from attempts to objectify and analyze it, to the recognition that beauty is culturally influenced, the understanding that art is about more than beauty, and the politics of beauty, for instance from a feminist perspective. I regard all of this as a separate subject, well reviewed in Cynthia Freeland’s 2001 book, But is it art?). Ultimately, faith tells me that it should be possible to find God in all things, including disease, cruelty, “wrong,” “ugliness.” Many of these things emerge from ego rather than Spirit. Finding God in them therefore will be more difficult, but should be possible.  Pursuit of that capacity is a legitimate spiritual Way. Thomas Merton, the philosopher monk, said, “Everything is beautiful.” Schopenhauer, according to Kirwin, argued that “everything would be beautiful if we could see it objectively.” Art philosopher Elaine Scarry (1999. On beauty) writes, “The beautiful thing seems–is–incomparable, unprecedented; and that sense of being without precedent conveys a sense of the ‘newness’ or ‘newbornness’ of the entire world…beauty is sacred…unprecedented…lifesaving…At the moment one comes into the presence of something beautiful, it greets you. It lifts away from the neutral background as though coming forward to welcome you.”

Red-winged Blackbird Dossier

by Carl Strang

Here’s another example of a species dossier. The idea is to separate what I have learned through my own observations from what I have learned through the literature or others’ observations. It is a tool that has enriched my understanding and improved my focus in the field. The initial summary, written when I established the dossier in the mid-1980’s, is followed by entries marked by my date code. Each month is represented by the first two letters of its name, except when two months begin with the same letter. Then, the second letter is unique to that month (JA, JE, and JL for January, June and July, respectively).

Blackbird, Red-winged

Nests seen in cattail marshes, attached to cattails, although birds also defend territories in dry, tall grass meadows. Out of breeding season may show up anywhere, though usually in open areas. Male advertizes with song (kong-la-ree’-er), either while perched or descending to perch on, say, tall cattail head. Capable of hiding or elevating and exposing red shoulder patches. When people approach nest, male especially but also female get highly excited, hovering overhead with sharp dry “keck” notes. Some individuals swoop down at intruders. Also chase crows, hawks. Hunt insects in breeding season, visit cornfields in flocks in fall. Gone from the north in winter.

5MR87. In morning, first of year on perches beside Butterfield Rd.

6MR88. Numbers of them at Winfield Mounds.

12MR89. First of year seen on way to Hartz Lake.

15AP89. Males often seen swiftly and closely chasing females, this time of year. Is she testing him, listening for wheezing, etc.?

1NO99. Last of the season seen at Willowbrook.

21FE00. Among several Brewer’s blackbirds at Fermilab’s buffalo feeders, a single male red-winged blackbird which called, once.

18JE00. A female flushed from a nest when I was about 10 feet away. Nest with 3 eggs, a woven grass cup ~3″ deep by 4″ across, attached to a dead woody stem in its fork, in a canary reed grass area and within the level of the grass, ~3 feet off the ground. Near edge of Herrick marsh.

22OC01. Some red-wings singing in the morning at south Blackwell.

31OC01. Flocks of red-wings and grackles remain (Nelson Marsh, Kane Co.)

4NO01. An enormous flock of red-wings and grackles along Kirk Road in eastern Kane County. The species were staying apart, on the whole, and there were mainly grackles, but there were hundreds of each. They were landing in a harvested corn field.

16MY06. Tri-County S.P. A male red-winged blackbird took flight and went straight for a pair of cowbirds foraging on the ground, more than 50 feet away. It chased them away, turning back as they kept going.

18MR09. Mayslake. Both red-wing and grackle include tail fanning and wing spreading in their displays. In the red-wing, these movements accompany the song but are expressed in a range from not at all or nearly so, slight fanning of tail, slight tail fanning and spreading of wings, much tail fanning and wing spreading.

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.

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