A Favorite Pin Oak Tree: 19th Century Origins

The Pin Oak tree at the edge of the road in Eliza Howell Park is one of my favorite trees. It stands alone, with enough room for its branches to spread. 

At this time of the year, the leaves are fallen and the branches are bare.

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I first started paying close attention to this oak because the birds are attracted to it. Warbling Vireos have nested here twice in recent springs and both Red-bellied Woodpeckers and Blue Jays are all over it in late September and early October, collecting acorns.

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Photo by Margaret Weber

This is a quite large – and old – Pin Oak, a species that does not live as long as some other oaks. After having been asked several times how old it is, I decided to try to find the answer. There is no exact method of knowing the age of a living tree, but there is a widely used method of estimating the age.

The steps in estimating tree age are these:

  1. Measure the circumference of the tree at 4 ½ feet from the ground.
  2. Divide the circumference by pi (3.14) to get the diameter.
  3. Multiply the diameter (in inches) by the “growth factor” that has been identified for the specific species, based on how fast growing it is. (Different organizations have published the growth factors for different species.)
  4. The resulting number is the approximate age of the tree, in years.

Pin Oaks are moderately fast growing and have been given a growth factor of 3.0.

It is difficult to measure the circumference of a large tree by oneself so recently, when accompanied by Charon, another Eliza Howell enthusiast, we undertook the measurement.

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At 4 ½ feet high, the tree measured exactly 12 feet in diameter (144 inches).

144 divided by 3.14 = 45.86.

45.86 times 3.0 = 137.58

Using this method to estimate age, the tree is about 137 or 138 years old.

137 years ago was 1883. This is just an estimate, but it is probably safe to say that this tree began to grow before the twentieth century, long before this property was donated to Detroit for parkland.

It was already over 100 years old when I started enjoying it, appreciating it in all seasons. On hot summer days, when someone else has not claimed the spot, I park the car in its welcome shade as I take my walk.

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Across the road is the prairie flower field and the Pin Oak sometimes makes a lovely background for a flower picture — Joe Pye Weed in this case.

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Pin Oak leaves turn late in the Fall, in November in Eliza Howell. The bronze (?) shade is not as striking as the leaves on some other trees, but there is something very attractive about it.

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As oak trees go, Pin Oak trees do not have a long lifespan. This one is perhaps older than average. I hope it continues to provide beauty, food, shade, and nesting habitat long after my nature walk days are over.

Golden-crowned Kinglet and Eastern Bluebird: Two Occasional Early December Birds

The completion this month of 15 years of bird watching in Eliza Howell Park (180 consecutive months and over 1370 different records) Park makes this a good time to review the seasonal presence of different bird species. Based on experience, I know fairly well which species I can expect to see in the park at any given time of the year, in any particular 2-week period. These can be considered Common for that particular “season.”

And I know the species that I do not usually see on my outings at a particular time of the year, but am not surprised when I do see them. These are Occasional birds, birds that I can expect to observe some years during this season, but not most years.

The current “season” is the first two weeks of December, a period of time characterized by cloudy days, with leaves on the ground but very few remaining on trees.

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At this time of the year there are no flowers blooming, no developing seeds or fruit, little evident insect activity; I tend to concentrate my observations on mammals and, especially, on birds.

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Recent sightings of two occasional bird species led me back to my records. The first is a Golden-crowned Kinglet, only the fourth time in the last 15 years that I have seen this bird in the park in December.

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Photo by Margaret Weber

In my listing of Eliza Howell birds, Golden-crowned Kinglet is identified as a Migrant, a bird that passes through the park in the spring and fall each year, but is not present in either the summer or the winter. It is a late fall migrant, usually seen well into November.

As can be seen from the range map below (from the Cornell Lab of Ornithology), the southern part of Michigan is within its winter (nonbreeding) range. Some Golden-crowned Kinglets can be seen in southern Michigan in winter every year, but my interest here is specific to Eliza Howell, the habitats in this particular location at this specific time of the year. Here it is occasional.

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The second occasional December bird recently seen is Eastern Bluebird. Bluebirds are Summer Residents, breeding in the park. They have become more common in recent years.

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Photo by Margaret Weber

This is only the third December I have seen a Bluebird in Eliza Howell. However, two of these three years are 2018 and 2019. As the species becomes more common during the breeding season, it may also show up on more occasions during the winter.
Similar to Golden-crowned Kinglet, the winter range of Eastern Bluebird includes southern Michigan, though most individuals migrate further south. (This map is also from Cornell.)

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I typically see about 24-25 different species in the park in December, most of which are the usual Eliza Howell birds of winter: Northern Cardinal, Red-tailed Hawk, Red-bellied Woodpecker, Dark-eyed Junco, Black-capped Chickadee, Mourning Dove, etc. They brighten the gray days.

The occasional appearance of a different species adds to the brightness and adds to my knowledge about what to expect when.

Eastern Bluebird: Becoming a Regular Nesting Species

Earlier this November, I watched several Eastern Bluebirds feeding in Eliza Howell Park, birds that were probably on a brief stopover during their southward migration. This observation started me thinking about my other observations of this species over the last 15 years.

The difference between the female and male Eastern Bluebird can be seen clearly in these two photos by Margaret Weber. The female is shown first here.

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Eastern Bluebirds were in serious decline throughout their range last century (especially from about 1920 till about 1970). They are insect eaters and a secondary cavity nesting species. Unable to make their own nesting holes as woodpeckers do, they need to find existing cavities. There were many reasons for the decline, including pesticide use, removal of dead trees, habitat change, etc. In addition, European Starlings, an introduced species that is also a secondary cavity nester, was much more aggressive about claiming tree cavities.

In the last 50 years, however, Bluebirds have gone from being endangered to being a conservation success story. One part of the turnaround has been the widespread use of Bluebird nesting boxes, made with an opening that is large enough for bluebirds but too small for the larger Starlings. Thanks to a birdbox making project of Sidewalk Detroit, there are now a couple such boxes in Eliza Howell Park.

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Fifteen years ago, I did not usually see Bluebirds in the park during the breeding season. Now I have seen them in most of the last 10 breeding seasons and they have probably been nesting here for several years (though I have not been able to make positive confirmation until recently).

The nesting box shown above was placed in the Spring of 2018 and has been used by Bluebirds both last year and this year. They usually have 2 broods per year, typically in the same nest. Note the evidence of the frequent use of the entrance hole.

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In late April this year, while the female was away from the nest, I put my camera in the box and took a quick picture.

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Recently, after nesting was finished for the year, I opened the box to clean it out for them to use again next year. My guess is that they added more nesting material after the first brood.

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The feather confirms the species that used the nest, if there were any doubt.

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Eastern Bluebirds migrate each spring and fall, but do not go very far south. Southern Michigan is at the northern end of the winter/year-round range. I occasionally see one or two in the winter in Eliza Howell, but I don’t really expect to see them again until March. (The range map from the Cornell Lab of Ornithology.)

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In addition to helping bluebirds find “housing,” nest boxes provide a good opportunity for bird watchers to see these lovely birds. Bluebirds need some open area (ideally something like a field with scattered trees) for their insect hunting. They are not likely to nest in small urban backyards, but Eliza Howell is now one urban location where there is a good chance to watch them in the spring and summer.

The next photo, also by Margaret Weber, taken at a different location, suggests some of the pleasure in Bluebird watching in nesting season.

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Gray Catbird: Predictable Departure Time

My October bird watching in Eliza Howell Park in Detroit is largely focused on birds Coming, birds Going, and birds Passing Through. “Coming” are those species that breed in the far North and spend their winters here; “Going” birds breed here and head south for the winter; “Passing Through” birds breed north of southern Michigan and winter to the south of us.

Very early October is the time to expect my last sighting of the year of one of my favorite park summer residents: the Gray Catbird.

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Photo by Margaret Weber

According to my records, the Catbird is typically here at the end of September but gone by the end of the first week of October. At this time of the year, I often walk through the wildflower field along the edge of the woods checking to see what birds have shown up overnight. The view is slowly transitioning to a Fall look.

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Birds like this area because it is a good place to forage for food, whether that food be insects or seeds (most of the wild flowers are now in seed) or berries from the many vines and shrubs at the edge. For most of the summer Catbirds eat insects, but when fruit is available as it is now, they eat a variety of berries.

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Photo by Margaret Weber

They are called “catbirds” because their wailing reminds people of a cat meowing. They are mimics, however, and especially when singing earlier in the season, can produce a great variety of sounds.

They spend the winter near the cost in the southeast U.S. or Mexico or in the Caribbean or Central America. (The Range Map is from the Cornell Lab of Ornithology.)

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Their spring arrival date is also predictable. I usually first spot one in the park between April 30 and May 4. Shortly thereafter they begin to seek out a nesting location; they place their nests in thickets, several feet off the ground. It often takes careful thicket searching, but I have had some success in finding their nests. Their eggs are a striking color (turquoise green?).

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Several pairs spend the summer in Eliza Howell Park. At least one Catbird was still present yesterday, October 1. It might have been the last day I see one in 2019, 5 full months after the first appearance in the spring.

Thank you for spending the time with us.

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Photo by Margaret Weber

One of the joys of nature watching for me is the predictability of the annual sequence of events. And very few events are more predicable than the time of  the annual departure from Eliza Howell of the Gray Catbird.

September 7 Nature Walk

The second of the annual Detroit Audubon field trips to Eliza Howell Park takes place on Saturday, September 7, 2019, starting at 8:00 a.m. The public is invited; there is no cost.

Timed to coincide with the early days of the Fall bird migration, this walk give special attention to birds, especially warblers headed from the North Woods to Central and South America. Depending upon the weather conditions, we are likely to see several warbler species, perhaps including these three. (Thank you to Margaret Weber for these three photos.)

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Black and White Warbler

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Nashville Warbler

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American Redstart

The fall warbler migration begins at the end of August and continues into October, with individuals of some 20 different species making short stops at Eliza Howell. The find from one day to the next is almost always different.

If September 7 is a good day, the birds will keep us quite busy, but we will also stop for non-bird observations. This is about the best time of the year to note the variety and nature of spider webs among the wildflowers and the shrubs. They vary in sizes and shape; this is a small one on a thistle.

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September is also the month when I most frequently see a Praying Mantis (or 2 or 3). They have reached maturity and may be seeking mates and/or laying eggs. (I wrote about “Praying Mantis Egg Laying” on September 13, 2018.)

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Butterflies continue to be present. One of my favorite late-season butterflies is the Common Buckeye, which makes it appearance in Eliza Howell after the July butterfly peak.

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I usually find several Bald-faced Hornet nests in the park each year, beginning about this time. We may want to stop for a look (through lenses) to watch the hornets enter and exit the hole near the bottom of these amazing constructions. (For more, see “Bald-faced Hornet Nests,” December 12, 2017.)

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Blue Jays migrate in September and many spend days at Eliza Howell harvesting acorns, from the middle of September into October. (For more information, see “Blue Jays Harvesting Acorns,” August 27, 2018).

September 7 might be a little early to see them at work, but we will check (this photo also courtesy of Margaret Weber).

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The seasons repeat themselves, so it is possible to predict what might be seen at any given time of the year. But it is also true that every day is different and almost every walk includes an element of the unexpected. Such is the nature of nature walks. September 7 should be fun.

Blue-gray Gnatcatcher Nest: The Rest of the Story

On May 28 this year, I wrote about finding an easily visible Blue-gray Gnatcatcher nest in Eliza Howell Park and concluded my comments this way:

“One of my goals each year for the June Detroit Audubon-sponsored field trip to Eliza Howell Park is to be able to point out an active Blue-gray Gnatcatcher nest, even if I cannot expect others to be quite as enthusiastic as I am about this tiny bird and its fascinating nest.”

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The field trip took place on June 8, which, according to my estimate based on observed behavior, was about day 10 of incubation (of a normal 11 – 15 day incubation period). When the our whole group stopped to look, the bird remained on the nest, watching us but not threatened enough by our presence to leave. Melissa Francese took this picture at that time.

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A few days later the eggs hatched. By June 18, when Kevin Murphy took the next two photos, the young were nearing the end of their in-nest development.

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It is difficult to tell because they were constantly moving, but my various efforts to count heads led me to conclude that there were probably 4 nestlings. While the female does most of the incubating, both female and male feed the young.

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They are now gone from the nest, successfully fledged as far as I can tell. While Blue-gray Gnatcatchers occasionally brood twice in a year, my nest watching of this species is likely over for the year.

They are nearly halfway through their stay of 4 + months in Detroit (arrive in late April and depart in September), spending the majority of their year far to the south. (Range map from Cornel Lab of Ornithology).

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I will continue to see them foraging in the park for a couple months (photo by Margaret Weber).

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And each time I see one, I will feel a sense of appreciation for weeks of enjoyable nest watching this year and for a highlight of the 2019 June Audubon field trip.

Bird Eggs: Some Quick Looks

Even when someone is able to locate a bird nest, that nest is usually in a location that does not allow for a good look inside; it may be in a tree cavity, high in a tree, or deep in a thicket. In my walks in Eliza Howell Park, I have, however, on occasion found nests that provide an opportunity to take a quick look – and quick camera snap – when the incubating adult is off the nest.

Note: Photos of the birds were all taken by Margaret Weber.

 Barn Swallow

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Barn Swallows regularly nest on little ledges under bridges and other structures. Their nests are mostly of mud, lined with softer material, including feathers. Cream-colored eggs, with dark splotches, represent a fairly common pattern among bird eggs. Each species, though, is a little different in size and coloring, in addition to having quite different nests.

Eastern Bluebird

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Bluebirds nest in cavities in trees or in nest boxes. Their practice of using nest boxes that humans provide has helped them recover from very low numbers a few decades ago and makes it possible sometimes to get a look at the eggs.

Song Sparrow

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Song Sparrow nests are well hidden in grasses and weeds and shrubs, sometimes on the ground and sometimes up a little. They are very skilled at not going directly to their nest when someone (like me) is watching. This year is the first time I have found a Song Sparrow nest and it happened when I was walking through tall grasses and the sparrow flew out at my feet. I looked down, pulled out my phone for a quick picture, then left. The eggs are small and they do not all look exactly the same.

Gray Catbird

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Catbirds nest in thickets and the few nests that I have seen over the years in Eliza Howell Park have been about 6 – 8 feet high. In my experience, the eggs that are only one color, not speckled or splotched, usually have no variation from one to another in the same clutch.

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Often my pictures of the insides of bird nests are not great quality photos. One reason is that I take hurried pictures of bird eggs; I do not want to stress the adults. Though absent from the nest at this moment, they likely know of my presence and I want to be gone as quickly as possible. I have often returned some time later and watched from a safe distance. I have been pleased to note that, in every case, the incubating adult has been back on the nest after my one-time quick close-up.