Bluebirds Nesting: April Delight

Eastern Bluebirds nest in Eliza Howell Park regularly, but in quite small numbers. They usually arrive for the beeeding season in March and begin nesting in early April. While a pair might use one of the bird nesting boxes that have been placed in the park, most seem to prefer finding a tree cavity in a wooded area, away from viewers like me.

This week I found a pair making a nest in a cavity in a small dead tree near the river. Since it is a very uncommon experience for me to find Bluebirds nesting in tree cavities, I asked Margaret for a photograpic record.

All the photos below were taken by Margaret Weber. Thank you.

The Bluebird is a popular bird in American culture, often featured in songs, poetry, and greeting cards. It is associated with happiness, with love, with beauty, and with sprng. The blue of the male (above) is striking, especially in sunshine in the breeding season. The less bright female is also lovely.

Almost exactly one year ago I watched as a pair of Black-capped Chickadees were working at this location, enlarging this hole for a possible nesting site. They might have started the excavation themselves but it looked to me at the time that the surface opening was not new, that it might have been started another year by Downy Woodpeckers. So the Bluebirds are the second or the third bird species to claim this cavity.

The nest, mostly of dried grass, is constructed inside the cavity primarily by the female, though the male brings some of the material to her.

Soon the female will begin laying eggs, perhaps a total of four. She does most, but not all, of the incubation, which lasts up to 19 days. Both parents tend the young in the nest, for up to three weeks. The male sometimes feeds the fledglings while the female starts incubating a second brood. (Bluebirds usually have 2 broods a year, which is perhaps a reason for starting this early in the spring.)

But today they are still nest building.

They are a delight to watch. And given the association with happiness and love, it seems especially fitting that the stem in the beak of the male (second last picture) is looped in the shape of a heart.

Honoring the Yellow Violet

Whenever I see the first blooming violet of the year in Eliza Howell Park, as I did this week, I think of the lines from Bobby Vinton’s song from about 60 years ago:

“Roses are red, my love / Violets are blue….”

Probably the primary reason for thinking of these lyrics is that the first violet in the park each year is not blue. It is yellow.

The Yellow Violet is the second woodland wildflower to bloom this year in the park, following Spring Beauty, which I wrote about last time.

Blue Violets are more common, but they come a little later. There are often found in the fields and in yards and are not restricted to woodlands. To me they look more purple than blue; the color violet was named for the flower, I understand.

There are other varieties and colors of violets, as well. This collage is of 4 I found on an April day last year.

Today I am honoring the Yellow Violet, a species that I was not aware of for a good part of my life. It thrives in the same rich organic Eliza Howell locations that are home to Spring Beauty and other early spring flowers, ike Cut-leaved Toothwort and Trout Lily.

Yellow Violet plants grow in clusters and often there is only one flower to a plant. The flowers are very small, maybe 1/2 inch across, on plants that early on the season are very close to the ground.

In this close-up look, it is easy to note the purple or brownish lines that are found most abundantly on the lowest of the 5 petals. Not quite so easy to see is the fact that the side petals are a little “bearded” or hairy.

The Yellow Violet (sometimes called Downy Yellow Violet) is native to almost all of eastern and central North America, though found only in some areas of each of these states and provinces. (The range map is from the USDA.)

The best time to view any of the early spring woodland wildflowers is on a sunny day, after the blooms have opened up after closing up overnight. On a cloudy day, they usually open only partially, as shown here, making the tiny flowers even more difficult to find.

Most people know that not all roses are red. Probably fewer know that not all violets are blue.

The poet William Cullen Bryant knew the Yellow Violet well and placed it very precisely in this part of spring.

“When beechen buds begin to swell / And woods the blue-bird’s warble know / The Yellow Violet’s modest bell / Peeps from last year’s leaves below.”

(Opening lines of “The Yellow Violet,” 1821)

Spring Beauty Is Rightly Named

I don’t usually see the first woodland wildflower blooms in Detroit’s Eliza Howell Park until a week or more into April, but the emergence of these perennials is weather-dependant. The recent warm sunny days have resulted in the first blooms along the forest path — the tiny Spring Beauty.

They are easy to miss, starting to bloom when the plant is only 2 – 3 inches tall; the small flowers are less than a half inch across. They are, however, definitely worth a close-up look, even if it means getting down on one’s knees.

The flowers vary in color from white to pink, with darker pink veins. They have 5 petals and 5 stamens ending in pink anthers.

The Spring Beauty grows among fallen leaves and twigs/limbs, in organically rich soil. Almost always they grow in the company of other spring wildflowers, but they are the first to bloom. This is the forest floor where the ones photographed today are growing, as seen from a standing position. One does need to stop and look in oder to see them.

Spring Beauty is a native wildflower of Eastern North America, blooming mostly under deciduous trees before they leaf out. (This range map is from the USDA.)

Depending on the weather, Spring Beauty may be blooming here for about a month. One can see the clusters of flower buds not open.

Many of the summer prairie wildflowers are big and bold beauties. Most of the earliest woodland flowers are delicate beauties. Spring Beauty introduces the season of the delicate beauties.

Small Milkweed Bug: New Observation, More Questions

On three different sunny days in mid-March, I found Small Milkweed Bugs on the ground in the wildflower field. It was the first time I have seen these striking orange and black insects this early in the spring.

Small Milkweed Bugs, like Monarch butterflies, feed on milkweeds as they develop. They are resistant to the mulkweed’s toxic compounds (cardiac glycosides) and able to take them into their own bodies, becoming toxic to potential predators themselves. And, like Monarchs, they announce this toxicity by their bright colors.

They overwinter as adults here, emerging from their winter shelters as soon as the weather warms. Monarchs also spend the winter as adults, but they migrate to warmer climates snd are not seen here again until May.

There were several milkweed bugs close together this week, suggesting that they winter together.

There is also a Large Milkweed Bug, very similar in apearsnce and behavior and more common than the Small MB in the park. Large Milkweed Bugs also overwinter in the adult form but might migrate some distance south. I am not sure, but I have never seen them here this early.

A Large Milkweed Bug is on the left; A Small Milkweed Bug is on the right.

Milkweed bugs lay their eggs on milkweed plants and the nymphs (which look somewhat like adults, but do not have wings) feed and grow there. They are often found in clusters.

I think the nymphs in this photo are Latge Milkweed Bugs. Perhaps this year I will learn the difference between the two species in nymph stage.

Milkweed bugs are seed bugs, extracting nutrients from seeds. This photo was taken last November, at the very end of the season.

I was surprised this week to spot a mating pair aming the early bugs. They reportedly lay their eggs on milkweed plants within a few days of mating, but this year’s milkweed plants have not emerged yet. The mating seems premature, but perhaps there is more for us to learn.

I thank these early Small Milkweed Bugs for the opportunity to observe more about their life cycle — and to start my 2021 insect photos. And I thank them for the reminder that there is more that can be learned on future Eliza Howell nature walks.

Brown-headed Cowbird: Being a Parasite Is Not Easy

One of the annual March arrivals in Eliza Howell Park is the Brown-headed Cowbird. I usually see the first one in the second or third week of the month; this year it was March 8.

The cowbird is not usually a sought-after species among bird watchers. It is common, not particularly striking in appearance, and few record its song. Thr first picture is of a female; the second a male.

Both photos courtesy of Margaret Weber

The cowbird is not a favorite, but it is well-known. It is a brood parasite, the most common brood parasite in North America. It lays its eggs in the nests of other species for them to hatch and feed.

Cowbirds got their name from their foraging practice of accompanying grazing mammals (originally bison on the Plains), seeking the insects that scatter as the animals move through grassland.

Not a forest bird, their range expanded to include a much larger section of the country in the 19th century as forests were fragmented. Their current range is indicated in this map fron the Cornell Lab of Ornithology.

A female Brown-headed Cowbird lays perhaps 30 eggs a year, usually one per nest of 30 different “host” birds. This means locating all these nests and knowing when the time is right to fly in and lay an egg quickly. They often remove one of the eggs already present. They pick a time when the clutch is conplete or nearly so and incubation is about to begin. (I pride myself in finding nesting birds in Eliza Howell, but a cowbird makes me recognize that I am just a beginner.)

They often choose the nests of species smaller than themselves with the result that their fast-growing chick has an advantage over its nest mates. Occasionally, they will parasitize larger birds; the smaller egg in this N. Cardinal nest is a cowbird egg.

Some host species recognize and remove cowbird eggs and some make new nests, but many cowbird eggs are successfully hatched. And fledged young cowbirds somehow find a way to join other cowbirds and not identify with / mate with their host species. The whole cowbird repoduction process is much more demanding than suggested by a common human judgment that they are taking an easy way out by letting other birds raise their young.

Occasionally, the cowbird might constitute a threat to an endangered species, as in the case of Kirkland’s Warbler here in Michigan. The warbler’s population plummeted following the transformation of its habitat and that same environmental change allowed cowbirds to enter the area. Kirkland’s Warbler had no inherited way of managing cowbird parasitism.

The Kirkland’s Warbler is a Michigan favorite.

Photo courtesy of Margaret Weber.

The Kirkland’s Warbler recovery plan included trapping and killing cowbirds.This might have been a useful short-term strategy, but the need says much more about the effects of human habitat change than it does about the behavior of cowbirds.

I have come to see the Brown-headed Cowbird as a bird with a fascinating history and unusual “nesting” practices. The more I learn about birds, the more impressed I am by the diversity of their behaviors.

I stop for a while when I see a female cowbird, She is worth watchung carefully.

Identifying Trees by Their Bark: A Challenge

On a recent walk in Eliza Howell Park, I focused attention on the bark of a number of mature trees. From a distance, the variations in color and texture may not be especially noticeable, but viewing close-up photos helps one understand how tree species can sonetimes be identified by the bark alone.

The trees in the first collage, clockwise starting from the top left, are: American Sycamore, Sugar Maple, Eastern Cottenwood, Yellow-bud Hickory (aka Bitternut Hickory).

Here is a second group of four. From top left, clockwise, they are: Pin Oak, Black Locust, Wild Black Cherry, and American Beech.

I took pictures of trees that I have gotten to know in the past, my identification being made on the basis of a variety of considerations — leaves, seeds/fruit/nuts, shape, size, and bark — not on the bark of the trunk alone. Even in winter, when there are no leaves on trees, the size and shape can be used to help identify the species, along with the bark.

It is very difficult for most of us, myself included, to identify trees by the bark alone. If the reader wants a challenge, try identifying the trees below. They are the same 8 as above, but in a different sequence. The real challenge is to identify them before looking back to the top.

The bark of each species has its own characteristics, but I find it much easier to recognize tree species when I have a little more complete picture.

March 1: First Day of the New Year

A naturalist once said to me that, in our climate, the new year begins in March, not January. I definitely agree. March is the month of new beginnings, new beginnings that I do not observe in Eliza Howell Park in January or February.

March is the month that the first of the birds returning from winter to the south arrive back in Detroit. Red-winged Blackbirds (the males come back earlier than the females) are often the very first.

Photo courtesy of Margaret Weber.

Another welcome return to the park each March is the Killdeer.

Photo courtesy of Margaret Weber .

March is the month when hibernating animals begin to emerge. On a sunny day in the middle of March I often see the first Garter Snakes of the year, warming in the sun’s rays on the brown grass.

And usually a little later in March, depending on the weather, Eastern Chipmonks can be spotted, venturing outside for the first time since they sought refuge for the winter.

It is nothing new to think of the new year beginning in March. Calendars have varied with cultures and have changed over the centuries.The Roman calendar which we use is a revision of an earlier Roman one that started the year in March. The month names “September, October, November, December” come from the Latin numbers seven, eight, nine, ten — an annual reminder that March once was the first month of the calendar year.

March in Eliza Howell is also the time when perennial flowers, long dormant, begin to green and grow.Two of the earliest are Blue Flag Iris and Violet.

While I have long recognized that nature’s new year begins in March, this is the first year that I am noting the beginning of a new year in my records.

If you happen to see me during my visit to Eliza Howell Park on March 1, perhaps we can exchange “Happy New Year” greetings.

The Cardinal Sings: Spring Is Nigh

The Northern Cardinal doesn’t sing in winter, at least this far north. It communicates with a softer chirping call until the days grow longer, when its loud whistling songs can again be heard.

I always expect to hear the Cardinal’s first “spring” singing in February in Eliza Howell Park. In 2020 I heard it on February 12. This year, it was on February 17, the coldest morning of tbe winter, when the snow cover was the deepest.

The snow was undisturbed in most areas of the park about 24 hours after the snowfall ended. The combination of a zero degree night and deep snow had apparently led most mammals to declare “a snow day” and stay in their shelters. About the only tracks visible, apart from a few scattered squirrel ones, were those of deer. Deer had been out browsing — and creating a number of crossing routes over the river.

The winter birds were active, however, foraging in the trees. I saw or heard 13 species, a high number for the middle of February.

Though I have been expecting to hear rhe Cardinal sing one of these days, it still caught me somewhat by surprise. Cardinals are one of the minority of song bird species in which both males and females sing. (The Cardinal photos here were taken at other times and locations.)

Photo courtesy of Margaret Weber.

Photo courtesy of Margaret Weber.

The Cardinal is traditionally a more southern bird, spreading north gradually in the 20th century. It is now one of the most best-known yard and park birds in southern Michigan. It does not migrate.

I was reminded of the attractiveness of this common bird a couple of years ago while doing some bird watching in Washington state. In a brief conversation with a local birder, I was asked if we had cardinals in our area. He envied those who did.

(Range map is from the Cornell Lab of Ornithology.)

When the Cardinal starts singing in February, the message is clear: winter is moving toward its end and it will soon be time to begin the cycle of life again.

When I heard the Cardinal sing this week, I began to think of Cardinals nesting in the park. Perhaps the singer and its mate did as well.

The Case of the Little Freeze-resistant Pond

On a sunny day near the end of January, I was walking in a pathless area of the floodplain in Eliza Howell Park when I came across a small pond in a dip in the ground, a little body of water that was unfamiliar to me.

What was most remarkable about the pond or pool was that it was not ice-covered. Other standing bodies of water that are not part of the flowing river had already been frozen over for weeks at this point. Before February it had not been a very cold winter, but cold enough to freeze non-running water.

I checked to see if the water was moving at all; it did not appear to be. There were some deer tracks near the water, but not many and it did not look as though the pond was a watering hole, at least at this tine of the year. I was curious and decided to come back for another look on a different day.

In the next visit, I realized that the pond, which I had stumbled upon the first time, was not easy to relocate. I needed to walk through thick understory growth.

Fortunately, I was able to follow my own tracks in the snow from a couple days before.

The pond was that day roughly 15 feet long and 5 feet wide. I could see nothing like bubbles or rising water suggesting that it was spring-fed (which could account for its remaining open).

Though the water looked clear, I was beginning to wonder whether it might be contaminated and a potential risk to the environment. When I got home, I emailed contacts in several different organizations seeking information about the possibility of getting the water tested.

On the next visit, the pond looked basically unchangedI, though we had now had several consecutive days of sub-freezing temperatures. I filled a small glass jar that I had brought with the clear water.

I left the jar on the floor of our unheated detached garage and the next day the water in the jar was frozen almost completely solid. Apparently there is not something in the water that acts as an “antifreeze.”

By this point I was getting responses to my inquiries. From the Michigan Nature Association came the suggestion that ground water might be seeping to the surface, despite the fact that no spring activity was visible to me.

Now that I know that the water removed from the site did definitely freeze, this explanation makes good sense to me. Ground water in this region is reportedly over 40 degrees F when it emerges from the ground. A regular supply of “warmer” water would keep much of the pond unfrozen, though I would expect freezing to occur at the pond edges, especially when the air temperatures in consistently below freezing.

In my most recent visit, such edge icing is noticeable.

So the puzzle is probably solved and I likely do not need to be concerned about contamination entering the river the next time it floods.

And I now know where to find a small, hidden, sunken pool of water to observe and to see what it attracts in the different seasons.

The Seasons: Quarterly Images

I walk more miles in my visits to Eliza Howell Park in the coldest days of winter than I usually do in other seasons. There are fewer day-to-day changes to catch my attention and stop me for closer looks; some of the life here is dormant now.

Recently, after I took a picture of the river from the footbridge, I reviewed seasonal images of the past year from that spot.

February 7, 2021

November 9, 2020

August 10, 2020

May 3, 2020

These times — early in February, May, August, and November– are good times to experience the heart of each season. The following pictures are examples of other photos taken in the park at approximately the same times of the river pictures above.

Staghorn Sumac seed cluster, February 7, 2021

Mushrooms/fungi on tree, November 10, 2020

Clouded Sulphur butterfly on coneflower, August 9, 2020

Gray Catbird nest, May 8, 2020

One of the great things about living in this geograpical region is that there are four distinct seasons to observe and enjoy. Whatever time of the year that I walk in Eliza Howell Park, I am well aware that seasonal change is coming soon.