Common Milkweed: A Frequent Stop

From May until October, Common milkweed is one of the flowers that I stop at regularly on my rounds in Eliza Howell Park. From being a “weed” in need of eradication, it has in recent years acquired both respectability and fame as a host plant for the larvae of the popular Monarch butterfly. I watch it for that role and for many other reasons.

In September, the plants, many of them 4 feet tall, are dominated by follicles (seed pods).

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When the seed pods open – and some are just beginning to do so – we can witness the delicate beauty of the seeds attached to the silk that allows them to be dispersed by the wind. This is definitely worth seeking out a sunny fall day.

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Common Milkweed is a perennial wildflower native to eastern North America that spreads both by seeds and by underground rhizomes, the second being the reason they are often found in patches. They sprout in May, usually shortly before the Monarchs return. (This year I saw the first Monarch on May 15.)

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Monarchs start laying eggs on the milkweed leaves almost immediately after arrival. Once hatched, the larvae (caterpillars) eat the tender leaves. This picture of a tiny caterpillar is from early June.

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By the end of June, milkweed is beginning to flower. I was especially struck this year by how fragrant the flowers are. Even for someone like me, who does not have the most sensitive nose, it is easy to know that one is in a patch of blooming milkweeds from the fragrance alone.

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Milkweeds get their name from the fact that leaves and stems, when broken, produce a milky sap. There is a toxicity in the milkweed plant and Monarchs acquire this toxicity from ingesting the leaves as caterpillars. The result is that adult Monarchs are not preyed upon by birds, who have come to know that Monarchs are not healthy food.

Monarch butterflies are not the only insect that benefits from using Common Milkweed as a host plant for young. In September, it is easy to find seed pods covered with Large Milkweed Bugs. In the picture, the left shows adult Large Milkweed Bugs and the right picture is of young ones (nymphs). (Yes, there are Small Milkweed Bugs, but not in this entry.)

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Large Milkweed Bugs have some characteristics similar to Monarchs: milkweed is the host plant on which the young feed; they are orange and black; they acquire a protective toxicity from milkweed; they migrate south for the winter.

I have recognized Common Milkweed for as long as I can remember, but I have only really gotten to know it from my observations in Eliza Howell Park in recent years. The more I know about it, the more I like it.

 

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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.

 

Some Recent FOYs

“FOY,” meaning first-of-the-year observation, appears frequently in my notes about my visits to Eliza Howell Park at this time of the year. There is something new to be seen every day.

Here are a few selected FOYs from recent walks, each of which seems noteworthy in its own way.

1.FOY Wild Lupine.

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Lupine tends to be the first to bloom each year among the flowers in native wildflower field at Eliza Howell. It is starting to bloom now and I always note it both because of its attractiveness and as a herald of all that is to come.

2.FOY Baltimore Oriole Nest

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Photo by Kevin Murphy

The nesting Baltimore Orioles are one of the highlights of the Detroit Audubon-sponsored field trip to Eliza Howell each June. (This year it is Saturday, June 8, at 8:00 a.m. – free and open to all.)

These orioles typically arrive in the first week of May and begin building nests in the third week of the month. The picture here was taken on May 18; the female was weaving.

3.FOY Burrowing Crayfish Hole

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Crayfish (also called crawfish and sometimes crawdads) are gilled and clawed crustaceans, related to lobsters. Some are terrestrial, spending most of their lives away from bodies of water. They burrow down to groundwater and come up at night to eat on land. They are nocturnal and I have no pictures from Eliza Howell, but this hole is evidence that they remain present in the park. This one will probably continue to remove mud as it digs deeper, piling it up near the entrance in the shape of a chimney (or volcano).

4.FOY Common Milkweed

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The common milkweed is a wildflower made famous as a host plant for Monarch butterfly eggs and larvae. Right after I saw the FOY Monarch on May 15, I checked a spot where I have found early milkweeds in other years. They are up and growing and will be ready any time the Monarchs are ready to lay eggs.

5.FOY Fledgling Robins

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The day after I took this picture of 4 young robins filling the nest, they left it. While I have been observing a number of different bird nests this spring, this is the first that I have watched successful fledging.

6.FOY Opossum Encounter

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On a recent walk in the EHP woods, I met this opossum along the path. “Possums” are nocturnal mammals and this daytime encounter reminds me that they are sometimes visible during the day. Maybe someday I see a mother opossum with several young on her back. That would be a great lifetime first (designated in my notes by “L” for “lifer.”)

7.FOY Honeysuckle Blossoms

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The redbuds and the crabapples have already been blooming for some time, but one of my favorite blossoms, honeysuckle, is just beginning. Most of the honeysuckle in the park have white blossoms, but a few, like this one, tend toward pink. The picture was taken on May 21.

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This list of recent FOYs could be considerably longer, but it is time to get away from the desk and back to the park to see what is new today!

Monarchs and the Milkweed Advantage

Monarch butterflies are again active in Eliza Howell Park. Monarchs are among the most visible and common of the roughly two dozen butterfly species found in the park and one of the few butterfly species that migrate (they head to Mexico each Fall). They have returned. To be exact, it is not the same individuals that have returned (their lifespan is not that long). But Monarchs are back.

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Photo by Margaret Weber

At the same time that I started seeing the first Monarchs of the year I began to notice that Common Milkweed, the wildflower that their life history is intimately connected with, have emerged and are growing rapidly.

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Monarchs use milkweeds (mostly the Common Milkweed) as the exclusive host plant for their eggs and larvae. They will soon be beginning the process. Nature walkers will be checking the underside of milkweed leaves for the Monarch caterpillar, almost as easily identified as the adult butterfly.

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Photo by Margaret Weber

Monarchs nectar on many different flowers (in the first picture above, it is on a butterfly bush), but its special relationship with milkweed in reproduction gives it what I think of as the “milkweed advantage.” There is a toxicity in all parts of the milkweed plant (ranchers/farmers are warned again letting their livestock graze it) and the Monarch acquires this toxicity from ingesting the leaves as caterpillars. The result is that adult Monarchs are not preyed upon by birds, who have come to know that Monarchs are not healthy food.

It is not a surprise that Monarchs like milkweed.

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Photo by Margaret Weber

The Monarch is one of the best known and best liked butterflies in this part of the country and there has been a growing concern in recent years about the decline in their numbers. They continue in good numbers in Eliza Howell Park, perhaps in part due to the limited mowing that allows milkweeds to thrive. 

The milkweed flower is followed by the seed pods, which will ripen and open to silky seeds that are dispersed by wind. 

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When I saw the first Monarchs last week, I immediately looked for milkweed. The two go together that closely. 

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Postscript: There is another insect that benefits from the toxic “milkweed advantage.” It is the brightly colored Milkweed Bug, found on the plants later in the year. That may be a story for another time. 

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