The Oil Beetles of Eliza Howell Park

I see Oil Beetles — large, dark, metallic-looking beetles – in Eliza Howell Park only in October and November. They are not particularly photogenic or otherwise likely to catch someone’s attention, but their story is part of the fascinating natural world that exists right here in the neighborhood.

I last saw one in 2019 on November 25, as it and I were walking on the park road.

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Oil Beetles, a type of Blister Beetle, are nearly an inch long and, when I see them, are walking slowly on the ground in or near the fields in the park. My earliest 2019 observation was on October 17 (next picture). They are not numerous; even in their “season” I do not see them on every visit.

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Oil Beetles are flightless. The adults emerge in the Fall and proceed in their slow and somewhat cumbersome walk toward a good place to winter in the soil. Based on the published research I have consulted, I think the female lays eggs in the spring, but I have seen them mating in the Fall. This pair was photographed in early November.

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They are called “Oil” Beetles because, like other Blister Beetles, they can secrete oily droplets from their leg joints when threatened. This “oil” contains a toxic chemical (cantharidin) that can cause painful blisters on human skin.

They have no hind wings and the short front wings cover only a small part of the large abdomen.

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Some Oil Beetles spend the immature phases of life in parasitic fashion in the nests of ground-nesting bees, eating the food that is brought in for bee larvae. 

There is much I don’t know about these beetles, but they now have my attention. I am sure that I will think of Oil Beetles when I next see ground-nesting bees.

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Beaver!

For the first time in the years that I have been engaged in nature study in Eliza Howell Park, I am now seeing signs of beaver activity. There are some 20 small trees near the river (the largest are about 4 inches in diameter) that have recently been cut down and removed.

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Beaver were an important part of Michigan’s history; the pursuit of their pelts was a major factor in the movement of Europeans into this part of the country. Unlimited trapping resulted in their being extirpated from this area some 150 years ago.

Some are now returning. In the last decade, they have been found along the Detroit River (including on Belle Isle) and a few have appeared in the Rouge River system. Until now, to my knowledge, none has been reported this far upstream on the Main branch of the Rouge.

I have not yet actually seen a beaver in the park (they are largely nocturnal), but I know of nothing else that cuts down trees and leaves these teeth marks.

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Young beaver stay with their parents until 2 years old or so, when they leave to find a mate and establish their own lodge and colony. Perhaps the signs of beaver activity in Eliza Howell mean that a new pair is taking up residence here, for the first time since long before this area was established as a park.

There is a lot I do not know about beaver from personal observation. They were not in the various areas I have walked regularly during my life and my observations of them when visiting other locations were limited. There is much for me to learn.

While most descriptions of beaver lodges are of conical lodges in a pond formed by a dam, they also make lodges in banks, with under water entrances, especially along rivers where the water is deep enough for them to swim under water/ice. The water level in the Rouge in the park varies throughout the year and I do not know whether it sufficiently deep to meet beaver needs. This is what it looked like on my last visit in the area where the beaver had cut trees.

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If they stay here, my guess is that they will be “bank beaver,” but one of the things I will be watching to see is whether they act to raise the water level, perhaps by using a current logjam as the start of a dam.

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Beaver are able to change the environment in which they live and this has sometimes led to them being considered by some as a nuisance or a pest (for example, when their dams lead to flooded roads). Their overall impact on ecosystems and on sustainability has, however, been viewed by most researchers as very positive, as evidenced in a widely-endorsed, and very readable, book published last year.

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I will also be looking for additional signs of their presence and of their behavior. So far I have not seen clear tracks in the mud, perhaps because most of the mud along the river is currently covered with leaves. The hind track (webbed) is reported to be about 6 inches long and the front about 3 inches. These drawings are from The Peterson Guide to Animal Tracks.

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I cannot say definitely that beaver have taken up residence in Eliza Howell Park, but I will now have a different answer when asked whether any beaver live here.

I have been saying “not yet,” hoping that they would show up one of these years. Now I can say “there are definite signs; let me show you.” Perhaps soon I will be able to give an unqualified “yes.”

Oriental Bittersweet: November Fruit

When the bright red and gold leaves of the Fall have fallen by the middle of November, there remains another red and gold attraction in Eliza Howell Park: the fruit of the Oriental Bittersweet.

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Though there are still a few remaining honeysuckle berries that the birds have not quite finished, bittersweet can be considered the last fruit of the season. As recently as September, it showed little indication of the starring role it would later play.

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Oriental Bittersweet is a vine that was brought to this country in the 1800s and has now spread widely. There is also a native North American Bittersweet vine, but the ones that I watch in Eliza Howell are the Oriental variety. It grows and spreads rapidly and can climb dozens of feet. The next picture shows the twinning nature of the vine; the following one gives an indication of its ability to climb trees.

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The outer seed covering totally hides the fruit inside until late Fall. Birds are not attracted until the outer shells begin to open, allowing access to the red fruit, usually after the bittersweet leaves have already fallen. 

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The gold shell, which opens in three parts, remains attached for a time (contributing to the attractive red and gold look) and later drops to the ground. The red fruit may hang on well into winter.

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Though Oriental Bittersweet might make for an attractive home decoration at this time of the year, people are rightly advised not to pick and transfer. Unless the seeds are very carefully disposed of, new plants could sprout, spreading the aggressive and hard-to-control vine. It is considered an invasive plant that may damage the environment.

The word “bittersweet” means pleasure accompanied by some negative feelings, sweet with a bitter aftertaste. The pleasure of seeing the red and gold fruit of Oriental Bittersweet can indeed be a bittersweet experience.

 

The River, the Season, the Weather: Tracking Fall 2019

I often stop on the footbridge during my walks in Eliza Howell Park, stop and take a picture, looking upstream the Main branch of the Rouge River. These pictures help me track seasonal changes and fluctuations in water level.

Below are 8 photos taken on different days during the four weeks from October 16 to November 13, 2019. Some from sunny days and some from cloudy days, these pictures presdent the progress of Fall this year.

October 16, 2019  (9:47 a.m.   Approximately 50 degrees F)20191114_172805

October 20, 2019 (3:04 p.m.   Approximately 60 degrees F)20191020_150414

October 24, 2019  (11:23 a.m.  Approximately 50 degrees F)20191024_112318

October 27, 2019   (11:57 a.m.  Approximately 45 degrees F)20191027_115727

November 1, 2019   (9:31 a.m.   Approximately 35 degrees F)20191114_173423

November 4, 2019   (10:22 a.m.   Approximately 45 degrees F)20191104_102257

November 8, 2019   (10:07 a.m.   Approximately 25 degrees F) 20191114_173718

November 13, 2019   (10:52 a.m.   Approximately 15 degrees)20191113_124144

The changes from the middle of October to the middle of November, always dramatic along the river in Eliza Howell Park, were even more dramatic this year because of the unusually heavy snow of November 11.

 

Kentucky Coffeetree: Watching Seed Pods

Since August, I have been checking regularly two Kentucky Coffeetrees that grow in Detroit’s Eliza Howell Park, paying them much more attention than I have in other years. My main interest has been the developing seed pods.

These pictures were taken in August.

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Kentucky Coffeetree is a tree native to, though not very common in, parts of the mid-west. Southern Michigan is at the northern end of its original range. It is now sold by nurseries and used as a landscaping tree. The size and location of the Eliza Howell trees suggest that they were planted here long after the park was established. They are both female trees, producing seeds.

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The seeds (beans) of the tree have been used – roasted – as a food in some Native American cultures and the Meskwaki (Fox) are said to have ground them for use in a hot beverage. Early European colonists also tried it as a “coffee” as well. (Unroasted pods and seeds are reportedly toxic.)

The seeds mature slowly. When the leaves began to turn in October, the pods were darker in color, but remained firmly attached.

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The pods vary in length, most about 4 or 5 inches long, much shorter but thicker than the pods of the Honey Locus tree, often seen on the ground at this time of the year. I placed the two together for comparison.

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Now, in early November, the Coffeetree leaves are down. But the seeds remain firmly on the tree; I have not yet found a single one that has fallen on its own. (I picked those that I have examined.)

This picture was taken this week.

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The pods are not yet as tough as they will get and the seeds, though considerably changed since August, are not yet fully mature.

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I sometimes refer to my visits to Eliza Howell as “doing research.” It sounds more serious than “going for a walk.” One of my current research questions is: “When will the Kentucky Coffeetree seed pods fall?” My hypothesis is that it will not be for at least another month.

It’s an exciting life I lead – watching seeds mature!

 

 

The Amazing Queen Hornet

In the early 1950’s, my siblings and I sometimes listened to the radio crime-fighting drama, The Green Hornet. That was then. Now the hornet I am thinking of is the Queen Hornet.

November is the best month of see Bald-faced Hornet nests in Eliza Howell Park. I walked past some of these nests many times during the last several months, but they were so well hidden in the (often maple) leaves that, despite their larger-than-football size, I found them only after leaves have fallen.

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The number of different hornet nests I see in the park varies from year to year. This year it was only 7 (so far), compared with about twice that many in each of the last two years. The winter of 2017-18 was colder than the previous two years, which is the likely explanation for the decline.

The nests I am now finding are finished; they no longer contain living hornets. Fortunately, I did find an active nest in August, low enough in a tree for me to approach and photograph. I was, of course, conscious of the need to approach carefully; “worker” hornets will sting repeatedly to protect the colonies.

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The white on the face accounts for the “bald-faced” name. They are also sometimes called “White-faced Hornets.”

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As I was taking close-ups, trying to be very quiet and deliberate, all went well until I accidently touched a twig on the tree. The vibration brought out some 10 – 12 defenders that buzzed around looking for the problem. I stood perfectly still and they eventually returned to the nest, apparently not identifying me as a threat. I went my way unstung.

The nests began about 5 months ago, started by a queen. At the end of the season, the inseminated new queens are the only survivors from the colony. A new queen leaves the nest and finds a location (such as under bark or rotting wood) to hibernate. In the spring, if she survives the winter, she will start a new nest all by herself.

Earlier this month, during a Wild Indigo Detroit field trip to Eliza Howell, someone turned over a rotten log to observe the life hidden there. One insect found was a Bald-faced Hornet. The location and time of the year suggested that it was a queen, though she was very sluggish and not very regal appearing.

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In the spring, a surviving queen selects a location, usually in a tree, and starts a new nest, using wood fiber. The nest is small at first but big enough for her to begin laying eggs. The first new hornets of the year are sterile females (the “workers”) who then take over nest building and raising young. The queen has the responsibility of producing more offspring. Typically, a mature colony has over 100 hornets.

Now that the season is over, there is often an opportunity to take a look at the structure of the nest, the home of a whole colony for one brief season.

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Since the nests that we can now find are no longer maintained and birds often open them searching for food, they will soon fall. They remind me of the life they supported in the summer.

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These empty nests also remind me of the amazing queen, hibernating in some hidden and sheltered spot, capable of starting a whole new colony by herself.

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.