Nature Discovery Day Is July 13

On Saturday, July 13,  there is a great opportunity for visitors to the park to become more familiar with the wildflowers, butterflies, birds, mammals, trees — and more – of Eliza Howell Park: 9:00 – noon. Free and open to everyone.

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There will be exhibits, activities, and options of guided walks designed to point out some of the natural wealth of this Detroit park. The park entrance is on Fenkell east of Telegraph. The event also includes an opportunity to learn more about the U-M wildlife motion-activated camera project (which includes Eliza Howell Park).

Among the highlights of mid-July are the meadow/prairie wildflowers. Among those catching my attention recently are these.

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Clockwise from top left: Foxglove Beardtongue, Black-eyed Susan, Butterfly Weed, Common Milkweed

The event is organized by Eliza Howell Park Partnership (EHPP), a coalition of persons with different organizational affiliations and a common interest in highlighting Eliza Howell as a place for observing and enjoying nature in an urban environment.

Guides will be present to assist in identifying the varieties of flowers, as well as the specific species of butterflies they attract. These are among the common butterflies at this time of the year.

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Clockwise from top left: Monarch, Common Ringlet, Red Admiral, Pearl Crescent.

While I am often unable to get a picture of a butterfly I see, it is never difficult to find flowers waiting to be photographed.

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Clockwise from top left: Staghorn Sumac, Chicory, Wild Bergamot, St John’s Wort.

Eliza Howell is the kind of nature park it is, in significant part, because the Rouge River runs through it. For those who wish to take it on Saturday, a short walk to the footbridge provides a good view of the shaded river.

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Back in the field, one flower not to be missed is Wild Bergamot, a mint family flower, sometimes called beebalm, that has only recently begun its summer blooming season. It is a magnet for a variety of insects. In this picture, the visitor is a Hummingbird Moth.

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Many mammals are more active at night than during the day. The cameras used in the UM wildlife camera project have located and identified some of the mammals of the night, as will be reported on July 13.

Two that I have recently seen during the day are White-tailed Deer and Groundhog.

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I thank EHPP for providing this opportunity to witness and enjoy the natural wealth of the park.

 

A Damselfly in Sunshine: Ebony Jewelwing

On some of these days in Eliza Howell Park, I can be tempted to avoid going to the river woodland because of the active mosquitoes. This is also the season of the Ebony Jewelwing, however, and the presence of this damselfly has lately been providing me with all the incentive I need to go to the near-river habitat, despite the mosquitoes.

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Damselflies are characterized by very large eyes (in proportion to the head) and a long thin abdomen. Ebony Jewelwing is a quite large damselfly, about 2 inches in length, and is the most common damselfly in EHP, based on my observations.

The size of the eyes always gets my attention.

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The adults that I watch are found fairly close to the river (though sometimes up to 100 yards away). The early stage of life is aquatic. They lay eggs on plant debris in slow-moving water and, after the eggs hatch, the young (known as naiads) spend the first part of their development in the water.

The adults often seek out leaves in one of the few sunny spots found in this habitat, and here I watch. The males and females are distinctively different. The male, pictured above, has dark wings with an iridescent green body. The most distinctive feature of the female is the white spot near the end of the each wing.

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Damselflies are carnivores, both in the larval stage in the water and in the adult flying stage. I watched this female eating another insect.

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A beginning bug watcher quickly learns the difference between damselflies and dragonflies, their near relatives. Both have 2 sets of wings and a long body. It is easiest to tell the difference when the insect is at rest. Dragonflies hold their wings out perpendicular to their bodies while damselflies hold their wings together across their backs.

Here is a resting dragonfly. They have even larger eyes.

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Dragonflies used to get more of my attention than damselflies. But that was before I came to know that Ebony Jewelwings are often resting (ready to be observed) in sunny spots close to the river near the end of June.

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Tulip Tree: The Bud Opens

One tree I visit regularly in Eliza Howell Park is a tulip tree. Perhaps I should say the tulip tree, since I am aware of only one in the park. I described the tree in my post on June 2, 2018 (“Getting to Know the Tulip Tree”).

During the last month, the tulip tree has been a primary focus of my observations on opening tree buds.

On March 26, 2019, the tulip buds still appeared dormant, with the same look that they had had all winter.

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In early April, the changes began. Note the progression in the next pictures.

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The “tulip” shape of the new leaves is now apparent.

In about a month, the flowers will be open. (This picture was taken May 29, 2018.)

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I expect to be there, watching and enjoying.

 

The Littlest Spruce: A Volunteer

One of my favorite trees in Eliza Howell Park is about 22 inches tall, considerably taller than when I first almost stepped on it three years ago. It is in a small clearing inside a wooded area of the park.

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Along the park road on the west side, there are over a dozen quite large spruce trees. The location, the spacing, and the size all suggest that they were planted when the park was being developed in the first half of the 20th century.

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The name “spruce” reportedly comes from the French “Pruce,” meaning Prussia, where such trees were believed to have originated. There are some 35 species of spruce in the world, with several native to North America.

Spruce trees are symmetrical, having the cone shape that many of us tend to associate with Christmas trees.

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One of the best ways to identify a spruce is by feeling its needles. Spruce needles are more or less quadrangled (4-sided), which makes them different from the other conifers that we typically find. The needles are attached to the stem singly.

A spruce has both female and male cones. In the spring, wind carries the pollen from the smaller male cones to female cones. The large mature cones hang down and many hang on through the winter.

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The little 22-inch spruce is several hundred yards from the others in Eliza Howell and it stands alone. It has no doubt grown from a seed that got carried there, more likely by a mammal than by a bird, I think.

Gardeners call them “volunteers,” the plants that come up from seed not planted by humans. That is, they call desirable plants “volunteers;” undesirable plants are, of course, called “weeds.”

The little spruce is a volunteer, one of the few volunteer spruces in the park, if not the only one. This is one reason it is a favorite tree.

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At this point I look down at the littlest spruce. If the tree thrives, in several decades someone will look up and see something like this.

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Meanwhile, I will watch as, if all goes well, it adds possibly as much as a foot to its size this year.

 

Thorns, Prickles, and Spines

I usually call them all “thorns,” all those sharp, pointed, stiff parts of plants that we usually become most aware of when they scratch, prick, or snag. Winter, with the absence of leaves, is a good time to look more closely at the branches and stems of the plants in Eliza Howell Park and to note the variety of “thorns.”

True thorns, botanically speaking, are modified branches. In EHP, they can be found on such trees as hawthorn (first picture) and buckthorn (second picture).

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Thorns grow from deep in the woody structure of the plant and are not easily broken off.

Prickles are also sharp outgrowths of plant stems, but they tend to be shorter. And, because they grow from the outer layers of the plant, they are more easily broken off.

I encounter prickles in Eliza Howell most often in berry patches (and prickles account for most of my scratches). This picture is of a wild blackberry cane.

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The plant that is most commonly recognized as having “thorns,” both historically and currently, is the rose. As in the French proverb (“No rose without a thorn”), the beauty of the flower is often contrasted with the hurt or risk from the thorn.

It does not sound quite the same to say it, but if we were to be scientifically exact, we would call roses prickly, not thorny. Rose “thorns” are prickles.

This picture is of the stem of a wild rose in Eliza Howell and the following one is of a garden rose.

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Spines are not easy to find in winter because they grow from the leaves and fruiting part of plants and drop with them in the fall. They tend to very thin and, while they might bend, they are often very sharp.

Note the spines on the thistle.

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I often warn field trip participants to be very careful when grabbing hold of a chestnut; the spines on the bur (outer shell) are sharp.

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Thorns, prickles, and spines all seem to have similar function, to help protect plants from herbivores. They simply take somewhat different forms.

I do not propose that we stop using the generic name “thorn” to apply to prickles and spines as well as to true thorns. I find it of interest, however, to note their differences. It is another little insight into the fascinating variations that exist in the natural world.

Inconspicuous Bark Specialist: The Brown Creeper

Occasionally between October and April I notice a small bird dropping down to the base of a large tree trunk during my walks in Eliza Howell Park. It is a Brown Creeper, a bird that can be easily missed, camouflaged as it is for its role as a bark specialist.

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Photo by Kevin Murphy

The Brown Creeper is the only member of the treecreeper family of birds that is found in North America. It feeds mostly on the insects (and their eggs and larvae) and on the spiders that it gleans from cracks in the bark, creeping up the trunk of trees from the bottom to near the top, probing in cracks in the bark as it goes. It then usually flies down to the bottom of a nearby tree and starts up that one.

Even the Brown Creeper’s nest is typically in/under loose tree bark. Detroit is at the southern edge of the Brown Creeper’s breeding range, but so far I have not seen any in the park during breeding season. They show up here in migration in the fall and spring and are sometimes found in the winter. Their presence is unpredictable and they are always in very small numbers; I see only one or two on the few days that I see any at all. (This range map is from the Cornell Lab of Ornithology.)

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While it usually climbs the trunks of larger trees, it can be found at times on smaller trees as well. Here, a side view shows the light-colored underside.

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Photo by Sharon Korte

This picture and the one below show how the Brown Creeper’s anatomy is suited to its creeping-up-the-tree and gleaning-insects-from-bark role. Note the long curved claws, the long stiff tail, and the decurved (downward curved) beak.

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Photo by Kevin Murphy

The Brown Creeper is a bird that is well named. Once seen and its behavior watched, it is not likely to be confused with other North American birds. Though inconspicuous, it is sometimes the highlight of a winter walk in the woods.

 

 

 

 

A November Walk: Reflections

Walking in the woods of Eliza Howell Park recently, I was noting how far advanced the trees are in acquiring their winter bare-branches look. It is November and trees are becoming dormant for the winter.

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Walking in the woods alone can be a time for reflection. As I approached the log of a tree that had fallen at least 10 years ago (one that I have watched slowly returning to earth over that decade), I focused on the fact that trees not only go dormant for the winter but they also die. Over the 14 years that this park has been my nature study area, I have seen many trees die and fall.

The tree in the next picture fell fairly recently and is now beginning to decompose.

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Long-lived species can live many years, but they do die. Perhaps we could say that they reach the November of their lives when they about 5/6 of their life expectancy.

Perhaps this maple is in the November of its life?

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If we were to live to be 90 (a long life), 75 is the beginning of our November. This would put me in the November of my life.

Humans are a long-lived species, but we have a limited lifetime. While we do not live indefinitely, life goes on. As we age, many of us think of the legacy, the contribution to future generations, we are leaving.

In another location in Eliza Howell Park, there is a young tree growing out of a rotting stump, a new tree of a different species from the stump.

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This might be a good image to reflect upon in terms of the legacy that we can leave: a place for others to grow and thrive, whoever they may be.

There is much to be observed and learned on nature walks in Eliza Howell Park. At times, this leads to reflections about our own lives. This is one such occasion.

Estimating the Age of Trees: November 11

Having learned recently about the effort to determine the approximate age of a large Bur Oak tree in the Rosedale neighborhood of Detroit, I decided to use the same method to arrive at an estimate of several large trees in Eliza Howell Park.

Anyone interested in assisting in this project is welcome: Sunday, November 11, at 1 p.m.

Please email if you are intending to come (so I can let you know if there is a late need to reschedule because of weather): leonard.weber9@gmail.com

This Pin Oak is one to be measured.

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The following steps are followed to get a non-invasive estimate of a living tree’s age:

  1. Measure the circumference at 4 and 1/2 feet from the ground (54 inches).
  2. Divide the circumference number by pi (3.14) to get the diameter.
  3. Multiple the diameter (in inches) by the growth factor which has been identified for the specific species. (Several organizations have estimated and published the growth factor for various species, based on how fast a species usually grows.)
  4. The resulting number is the approximate age of the tree, in years.

Another of the trees I plan to measure is this American Sycamore.

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I am hoping to measure about 8 large trees, different species, ones that are often noticed by park visitors and participants in nature walks. At present, when I am asked “How old do you think that tree is?” I can only give a general response.

This Eastern Cottonwood, the location of a Baltimore Oriole nest every year, is also on my list of trees to be measured.

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I have been asked specifically about the approximate age of the Bur Oak (next picture) at the edge of the path leading down to the floodplain.

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In my initial use of this formula for estimating tree age, I have found that not all online sites of growth factor information have the same number for a particular species. It will be necessary for me to do more research before November 11 in order to determine the most appropriate numbers to use.

As I noted in a February post (“Beech Trees and Beechnuts”), Passenger Pigeons used to eat many beechnuts. I am wondering whether this American Beech is old enough to have been visited by those legendary birds.

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As I get to know more about the flora and fauna of Eliza Howell Park, I realize how much more there is to know. And I look forward to this learning project.

 

 

Sugar Maple: A “Leaf Peeping” Walk

When asked recently what my favorite kind of tree is, I said that it depends on the season. Different trees attract me at different times of the year. Twice a year – in March and in late October – the Sugar Maple is at or near the top of my list of favorites in Eliza Howell Park.

In March, it is “sugaring” time (see “Maple Sap Rising,” March 13, 2018); now the leaves demand attention.

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A number of Sugar Maples are found near the park road. The leaves are thick and the branches hang low. (It is a good tree to duck under to wait out a brief rain.) When the leaves turn in the fall, they can be yellow or pink or red, often on the same tree.

Note the variety of colors of the leaves on the ground here, all from the same tree.

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Each fall I check the next two Sugar Maples, growing side by side, to see how both the colors and the time of leaf drop differ.

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These close-up pictures of Sugar Maple leaves, still on the trees, are put together for easy comparison.

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Sugar Maples, native to Northeast North America, are one of the featured trees on many fall foliage viewing (“leaf peeping”) tours in New England and the upper Midwest.

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Healthy Sugar Maples can grow to over 100 feet tall and live up to 300 – 400 years.

Using a method of estimating the age of a tree based on its circumference (a method to be described more fully in the next post), I estimated that the Sugar Maple pictured below is about 180 years old. This means that it began to grow here about the time Michigan became a state.

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The Eliza Howell Sugar Maples mean tasty maple syrup to a number of park neighbors, but that is only one way in which they contribute to the natural beauty and fascinating features of the park.