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Mink by the River
Leonard Weber
January 14, 2025
Last week, while on a morning nature walk, Kathleen Garrett and I saw a Mink traveling along the river in Eliza Howell Park. It trotted downstream on the ice along the river’s edge.
Rouge River. January 9, 2025 Over the years, I have occasionally seen a Mink in the park. Each time, it was quite early in the morning, and the Mink was always on a log in the river or right at the edge of the water. Mink is crepuscular (especially active at dawn and dusk) and semi-aquatic, so both the time and the location are expected.
American Mink is widespread in North America, though not frequently spotted or photographed in the wild.
Photo courtesy of
Melissa McLeodMink, a mammal in the weasel family, is best known for its fur. It does not seem to be known very well otherwise.
It is usually solitary, except in breeding season (late winter to early spring). The male does not participate in caring for the young.
Mink often den in river banks, sometimes in hollow logs or in crevices. They are good swimmers and can climb trees. They do not hibernate.
Photo courtesy of
Karen PanagosThey may appear non-threatening in appearance, but they are aggressive carnivores. In the winter, they eat mostly mammals — rabbit, muskrat, and smaller rodents like voles. In other seasons, their diet includes fish, amphibians, crustaceans, even birds.
Photo courtesy of
Kevin MurphyNow that we know Mink is present here this winter, narure walkers can consider this species among several others in examining tracks in the snow by the river.
Sometimes, a Mink uses a bounding, jumping run. The front feet come down together, then the hind feet land in the same spot as the front feet take off again.
Probable Mink bounding tracks.
Photo courtesy of Kevin MurphyIt’s a good winter when we have both Beaver and Mink on our minds while walking along the Rouge River in this Detroit park.
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Merlin and Beaver: Winter Nature Walk Agenda
Leonard Weber
January 4, 2025
In Eliza Howell Park, January and February are quiet months, months with no major seasonal changes in what nature walkers observe: no migratory bird species arriving or departing, no trees leafing out or dropping leaves, no flowers opening or going to seed, no butterflies to watch and photograph.
Despite it being the quiet season, there is always something that leads to further observation and learning.
This winter, there are two important questions determining the direction of many of my cold walks in the park.
1. What is the Merlin’s prey?
Starting in late fall, there has often been a Merlin perched on a tree limb in the same general area of the park. I now look for the small falcon every time I approach the scattered Wild Black Cherry trees. It can usually be recognized by its silhouette as it perches on a high limb on a gray winter day.
Probably the same Merlin on three different Black Cherry trees on three different days in Dcember 2024. Merlins hunt from an open perch. They turn their heads frequently, looking for prey on all sides. They are raptors, with small birds making up the major part of their diet. When they spot something, they take off at a high speed and are often able to overtake and snag a fleeing bird.
Merlin. Photo courtesy of Margaret Weber. Merlins are only around Detroit in the winter, and this year, one is a regular in the park. The fact that it continues to select its hunting perch in the same general area is likely to mean it has been successful in its hunts here. I have not yet been able to see what its prey is this year, however, so I am planning to increase my observation time in search of an answer.
One of the amall birds that feeds on or near the ground near the Cherry trees is American Tree Sparrow, often foraging in a small flock.
American Tree Sparrow.
Photo courtesy of Margaret Weber.Merlins are patient predators, sometimes remaining on the same perch for a long time. In order to identify its (attempted) catch, I, too, will need to be patient, spending longer periods of time (in the cold) watching.
First two January 2025
nature walks.2. Will the Beaver stay all winter?
The Beaver is a mostly nocturnal mammal, so it’s no surprise that I have not had an actual sighting of the legendary rodent in Eliza Howell Park. However, there have been abundant signs of its (their?) presence since the beginning of November 2024.
The only other time in recent history there were similar Beaver signs was from November 2019 till January 2020. One or a pair was here for about two months before moving on (or before something else happened).
The nature walk route this winter will regularly include the different areas along the river where the beaver has been active.
So far, the evidence of its continued presence has consisted of felled trees and gnawed bark. It appears to be carrying away small limbs for winter eating, but the location of food storage or of a bank den remains unknown. There is much more to be observed and learned.
Photo taken during a
December 31 walkNature walks are, by definition, always open to the unexpected and to revisiting known flora or fauna sites to gain additional information or insight. A pre-planned agenda needs to be flexible.
At least as of now, however, the Beaver and the Merlin questions are likely to be on my mind on every walk.
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The Seven Woodpeckers of Eliza Howell Park
Leonard Weber
December 24, 2024
There are eight different members of the woodpecker family normally found in Michigan. All but the Black-backed Woodpecker, an uncommon species of the northern forests, have been observed in Eliza Howell Park in Detroit.
In 2024, for the first time in 20 years of nature walks, I have seen all seven here in the same calendar year.
Woodpeckers as a group are distinctive enough to be recognized with a little experience. They have straight chisel-like beaks, are frequently found on trees, and most have an undulating flight with small swoops. It is common to hear their pecking (hammering) on tree trunks or limbs, behavior that makes it easier to locate them.
Red-bellied Woodpecker (male). Photo courtesy of Margaret Weber The Red-bellied Woodpecker is probably the most common woodpecker in the park, present every month of every year. This would not have been true a couple (human) generations ago; they have extended their territory northward since the mid-20th century.
Red-bellied Woodpeckers nest in standing dead trees or large dead limbs of a live tree. It is often easy to find them at work excavating a nesting cavity in the spring; their hammering and loud calling announce their location.
Most woodpeckers, including all of the Eliza Howell species, have two toes in the front and two in the back of the foot (most other bird species have three front and one back). The two back toes, together with stiff tail feathers, facilitate clinging to the side of trees.
Downy Woodpecker (male). Photo courtesy of Margaret Weber Also very common here is Downy Woodpecker, the smallest of the seven. It is present year round and is frequently seen on tree trunks as well as smaller limbs probing for insects, insect eggs, and larvae. It sometimes forages on dried stalks of wildflowers or other tall plants.
Downy Woodpeckers often excavate their nesting holes on the underside of a slanting dead limb.
Hairy Woodpecker (female). Photo courtesy of Evan Deutsch Hairy Woodpecker is the third Woodpecker present throughout the year in the park. It is less common than the two above and less likely to be seen outside the woodland.
A Hairy looks like a slightly larger version of a Downy. The size of the bill is a key indication of the difference.
Almost all woodpeckers drill a new nesting hole every year. The hole is usually quite deep and, once the hole is large enough for it to get its whole body inside, the excavating bird comes to the opening to “spit” out the chiseled pieces.
Northern Flicker (male).
Photo courtesy of Margaret WeberThe Northern Flicker also nests in Eliza Howell Park. It is different from the three above in that it migrates (but not a long distance). While one might occasionally be seen in the park in winter, it is essentially a breeding-season-only resident.
Flickers often feed on the ground, ants being a favorite food. When they fly up away from the watcher, the white spot on the rump is evident and one way of identifying the species.
Yellow-bellied Sapsucker (female).
Photo courtesy of Margaret WeberYellow-bellied Sapsuckers breed north of Detroit and winter to the south. They migrate through twice a year and are most likely to be seen in April and October.
Especially at the time of their spring stopover, one can see how sapsuckers seek food and how they got their name. They drill a role of holes (“sap wells”) in the bark of a tree, then return periodically to snag the insects attracted to the sweet sap as well as to feed on the sap.
There are other sapsuckers in the west, but Yellow-bellied is the only one in eastern North America.
Red-headed Woodpecker.
Photo courtesy of Margaret WeberThe caption does not specify the sex of the bird in this photo because female and male adult Red-headed Woodpeckers look alike.
This species makes only an occasional appearance in Eliza Howell Park. A single bird shows up every 3 – 4 years on the average, usually in the summer, and stays for only a day or two. This year, one was sighted in June.
Red-headed Woodpecker numbers have been declining, though they are a little more common south of Michigan.
Pileated Woodpecker (male). Photo courtesy of Margaret Weber This is the largest of the seven park woodpeckers (it is about the size of a crow) and is the most recent addition to the list of woodpeckers seen in Eliza Howell.
Pileated Woodpecker is a non-migrating species that requires large trees. Each pair claims a significant area for its territory. In the last couple years, including early 2024, one was seen in the park for a brief period of time. There is no indication that they have taken up residence here yet, but they will be a splendid addition if and when they do.
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It has been a pleasure to get to know the Eliza Howell Park members of the woodpecker family. They include colorful species; some are quite vocal, with distinctive calls; woodpecker nesting and foraging behavior can often be observed. And there is no time during the year when they are all absent.
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An Admired Beech Tree: Its 3rd Century
Leonard Weber
December 19, 2024
An area within the road loop of Eliza Howell Park contains scattered mature trees. The trees are primarily Oak, Cottonwood, and Black Cherry. Among them is one, only one, large American Beech.
American Beech The other large beech trees in the park are in the woodland where, as is usually the case with forest trees, they have grown tall with few lower side branches.
Woodland Beech The Beech featured in this post has many horizontal branches, starting quite close to the ground.
The tree spread is impressive, up to 40 feet from the trunk to the end of low branches.
This spread allows nature walkers easy access to the leaves, nuts, and buds.
Beechnut 
Buds in winter The large horizontal limbs seem to project character and strength.
It is clear that this tree has been here for a long time. Recently, I have been wondering how long.
There is a method for estimating the age of a tree based on the size of the trunk. The first step is to measure the circumference of the trunk at 4 and a half feet from the ground. Dividing that number by pi (3.14) gives the diameter. The diameter, in inches, is then multiplied by the growth factor of the particular species (lists of the growth factor of many tree species are published by different organizations.) The growth factor is based on how fast a species tends to grow.
This Beech tree has a circumference of 10 feet 3 inches — or 123 inches — at 4 and a half feet high. Dividing 123 by 3.14 = 39 inches in diameter.
American Beech is a relatively slow growing species, with a growth factor of 6. 39 times 6 equals 234. Based on this method, the tree is estimated to be about 234 years old.
This aging method is a quick way of estimating the age of a tree and is not exact. It does confirm, however, that this is indeed an old tree.
234 years ago was 1790. George Washington was President in 1790. Later, in 1802, the city charter for Detroit was approved. It incorporated a city of about 213 acres; the city size is now about 139 square miles.
This tree was growing here all (or nearly all) of these years.
Passenger Pigeons, once abundant in Michigan, were hunted to extinction over a century ago.
One of the favorite foods of Passenger Pigeons was beechnut.
This Beech, mature enough to produce nuts during much of the 19th century, may have been visited by hungry Passenger Pigeons.
Stem bud showing promise of 2025 growth I admire this American Beech tree as a strong, attractive, and durable example of the species. I admire it also as a reminder of the ways we are connected to the past as we walk and observe nature in the park.
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Birds of December: The Regulars and the Occasionals
Leonard Weber
December 9, 2024
In December 2024, I am completing 20 years of bird walks in Detroit’s Eliza Howell Park. With observation records from 240 consecutive months, I have a pretty good understanding of what to expect to see at any given time of the year.
The average number of observed bird species in December is 25 (only January and February have fewer). Of these 25, about 20 are fully predictable, birds that can be expected to be here almost every year. These are the regulars.
There are also always a few less predictable, another 15 or more species that occasionally show up in this month.
Most of the regulars are year-round residents in the park, found here all four seasons. Here are 10 of them.
Red-bellied Woodpecker.
Photo courtesy of Margaret Weber
Carolina Wren.
Photo courtesy of Kevin Murphy
Red-tailed Hawk.
Photo courtesy of Margaret Weber
Northern Cardinal, male and female.
Photos courtesy of Margaret Weber
Blue Jay.
Photo courtesy of Margaret WeberI sometimes refer to four species that sometimes move through the trees in winter in proximity to one another as “the foraging four.”
Top: Black-capped Chickadee and Tufted Titmouse.
Botton: Downy Woodpecker and White-breastfed Nuthatch. Photos courtesy of Margaret WeberOne of the common birds of winter is not a year-round resident. The Dark-eyed Junco spends the breeding season north of here; southern Michigan is part of its winter range. It is reliably present here for some six months beginning in October.
Dark-eyed Junco.
Photo courtesy of Margaret WeberIt is much more difficult to predict which of the species that occur only occasionally in winter will show up in any specific December (or January or February). This sense of “what might I see” is part of the incentive to go out again and again on cold winter days.
In recent years, there has been a relatively good chance that I will see a Merlin (a falcon that sometimes winters in urban areas) at least once during the winter months. It has already been present this month.
Merlin.
Photo courtesy of Margaret WeberThough I definitely do not see them every year, I frequently check birch trees during my winter walks for Common Redpolls. These small birds, usually in flocks, are quite rare visitors from the north. When in the park, they are typically found eating birch tree seeds.
Merlin preys upon small birds and, if it is present at the same time as the Redpolls, a chase is almost inevitable
Common Redpoll.
Photo courtesy of Margaret WeberGolden-crowned Kinglet is another small species that is occasionally present in the winter months. It breeds north of here and there are always a number of them in Eliza Howell Park in the spring and fall as it migrates through. This is the northern edge of its winter range, so it can be seen here occasionally in winter.
Golden-crowned Kinglet.
Photo courtesy of Margaret WeberThe birds only occasionally in Eliza Howell in winter include a couple that breed here before going south for the winter. One is Eastern Bluebird. This is another case of being in the northern section of its winter range. It is rarely present in the park in winter. When it is, it brings a bright light to winter.
Eastern Bluebird.
Photo courtesy of Margaret WeberIt is always rewarding to see the winter regulars. Thank you for being here again this season.
It is always rewarding to see the winter occasionals. Thank you for your visit.
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The Progress of Fall 2024: Photos from the Footbridge
Leonard Weber
December 2, 2024
It takes about two months, essentially the months of October and November, for the leaves on the various deciduous trees along the Rouge River in Eliza Howell Park to complete color change and to fall.
Here, in 10 photos, is the way Fall progressed along the Rouge in 2024.
October 1, 2024 
October 8, 2024 
October 14, 2024 
October 23, 2024 
October 30, 2024 
November 6, 2024 
November 12, 2024 
November 17, 2024 
November 26, 2024 
December 2, 2024 The photos were taken from a spot near the middle of the footbridge, looking upstream.
The footbridge over the Rouge River in Eliza Howell Park -
Trees in Winter: Bark, Buds, and More
Leonard Weber
November 25, 2024
For the next 4 months or so, the trees in Eliza Howell Park will be dormant, with very little change in their appearance. Though dormant, the trees are definitely not featureless, and these months provide good opportunities to get to know deciduous trees in the leafless season.
Winter is an ideal time to walk in the woods. A view of the dozens of leafless trees of various ages is an invitation to walk among them.
I find myself returning often to my winter photos of the river looking upstream from the footbridge. Especially when the sky is blue, the light-colored bark of the Sycamore tree on the right demands my attention.
In the absence of leaves, the bark of trees is more often a center of focus. While it can sometimes be incredibly difficult to identify some trees by their bark, the bark patterns of a few species are distinctive.
Hackberry 
Wild Black Cherry 
Shagbark Hickory Sometimes, a tree’s bark is nearly covered with lichen.
Gold Dust Lichen on Red Maple When the tree limbs hang low enough to allow the examination of the ends of stems, (usually where trees are not crowded, less likely in the woods), one can get to recognize the characteristic shape and color of stem buds.
From top left, clockwise: Hawthorn, Eastern Cottonwood, American Sycamore, Norway Maple It’s both challenging and satisfying to get to know a number of tree species by their buds, present throughout the dormancy months.
From top left, clockwise: Chinkapin Oak, Yellowbud Hickory, Sugar Maple, American Basswood Some tree species are leafless, but still retain their dried seed pods well into winter.
Eastern Redbud Though, in general, deciduous trees have lost their leaves, there are some trees where dried leaves hang on for the winter, a phenomenon known as marcescence. In Eliza Howell Park, this most commonly happens with a few oaks.
Shingle Oak trees in winter Winter tree watching sometimes includes watching various types of fauna that can be seen in or by trees, attracted by shelter or food opportunities.
Racoon 
Common Redpoll among birch seeds I invite you to take one or several winter tree walks this year. Don’t forget to bring a camera!
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Eastern Screech Owl: A Good Day’s Sleep
Leonard Weber
November 19, 2024
The Eastern Screech Owl is an Eliza Howell Park bird species that doesn’t usually make the record of birds observed during nature walks. It is nocturnal — and this nature walker tends to be diurnal.
Daytime observation of Screech Owls in non-breeding season depends upon spotting one that is roosting. Knowing that they sometimes roost in a cavity, a colleague and I recently checked a Wood Duck nesting box in the park.
Before I opened the box, I knocked on the side to give anything inside a chance to get away. When nothing stirred, I opened the box.
I have done this many times, and this is the very first time that an owl was present. It appeared to be sound asleep.
In nesting box placed for
Wood DucksScreech Owls don’t always use the same locations for daytime roosting. Sometimes, they use tree cavities; sometimes, they find a nook outside, perhaps close to a tree trunk. They are difficult to spot, in part because of effective camouflage.
Photo courtesy of Margaret Weber 
Photo courtesy of Margaret Weber They emerge/awaken to hunt at dusk. They are predators with an extensive diet, often hunting from a perch. In the warmer season, they frequently eat invertebrates like insects, worms, and snails. In winter, they tend to eat a variety of small mammals and birds.
Eastern Screech Owl is found in most parts of the eastern half of the country. It does not migrate.
Range map from Cornell Lab of Ornithology Screech Owls nest in tree cavities and live almost anywhere there are trees. They appear to be comfortable around humans, often found in urban and suburban neighborhoods and parks.
As cavity nesters, they sometimes select a bird box for their nest. This particular box has been used in the past by nesting Wood Ducks.
Wood Duck eggs, 2023 It is possible that this box could be used by a pair of Screech Owls for a nesting site next year. This individual, I suspect, was not yet focused on selecting a nesting site.
After a hard night hunting, it was probably just seeking a cozy site for a good day’s sleep.
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Beaver Fever: Exciting Signs of the Famous Rodent
Leonard Weber
November 10, 2024
Fall color season is over in Eliza Howell Park.
November 8 As often happens in the park, however, when one feature attraction fades, something else appears.
The new excitement is the presence of American Beaver. Beaver is mostly nocturnal, so I have no photos of the actual animal. “Observing” beaver consists of looking for and trying to learn about the animal from the signs of its nighttime activity along the river.
My Nature Walk colleagues Kathy and Mara first spotted a beaver-felled tree on November 1.
Beginning in the mid 1500s and continuing for about 3 centuries, felt top hats made from beaver pelts were fashionable among some European males. When beaver became scarce in Europe, suppliers began to seek the pelts in North America.
The beaver fur trade was a very important factor in the exploration (and settlement) by Europeans of large parts of North America.
In the 1800s, the once common American Beaver was trapped to near extinction — and silk hats became fashionable.
In the 21st century, after being extirpated here by the end of the 1800s, beaver has finally begun to return to rivers in southeast Michigan.
Beaver is a semi-aquatic mammal. Their dens (sometimes lodges, sometimes burrows in banks) normally have underwater entrances. They store their food under/in water.
This November marks the second time in recent years that there have been clear signs of beaver presence in the Rouge River in Eliza Howell Park. The other was November 2019. At that time, there were no new signs after several weeks. The beaver(s) apparently moved on, leaving behind many little stumps.
At about the age of two years, young beavers leave their family home to find a territory of their own; they might travel several miles. Perhaps the signs of beaver presence here, both now and 5 years ago, mean young beaver(s) starting out.
One of the fascinating things about beaver is that they can eat cellulose, which normally cannot be digested by mammals. In addition to small limbs and twigs, they eat bark and the soft tissue under the bark (cambium).
They often carry away, for later eating, the limbs and twigs of small trees they cut down. They gnaw the bark of larger trees. These are some of the easiest beaver signs to find as one walks the path along the river.
A close look at a cut tree shows the marks left by the famous beaver teeth.
It’s not possible to know now whether this time beaver will quickly move on or take up residence here.
At present, it’s exciting to “watch” a mammal that is unusual in Detroit parks. It’s exciting to know that a mammal of such historical importance has returned. It’s exciting to think that beaver may be a more common presence here for future generations than they have been for mine!
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Deer Tree Rubs: Mating Season Begins
Leonard Weber
November 4, 2024
Whitetail Deer are common in Eliza Howell Park, so common that I rarely give much attention to them on nature walks.
This year, however, I have seen four bucks together a couple times, something that is not common here.
The beginning of November is approximately the start of the deer mating season in Michigan (often called rutting season). This is a good time to look for small trees that have had some of the bark rubbed off.
Bucks use their antlers to scrape the bark off, then rub their forehead glands on the bare wood, leaving their scent. While some have suggested that this behavior is a territorial signal to other males, it might be more related to getting the attention of females in the area. Whitetail males are not known as very territorial.
I came upon this rubbing buck last November. (Unfortunately, the photo is not very good.)
Some tree rubbing begins in the summer when the males are trying to shed the velvet from their new antlers, but the number of rubbed trees increases dramatically at this time of the year. It is the easiest-to-find indication that mating season is (nearly) here.
The trees selected are usually quite small, with trunks of about 1 – 2 inches in diameter.
I don’t expect to see a number of mature bucks together this month, as I did earlier. They are now each involved in seeking a receptive doe. The gestation period of Whitetail Deer is about seven months, typically November to June here. In July and August, when walking through meadows, I sometimes come across a young fawn in its daytime hiding spot.
For now, however, bucks are (trying to be) the attention getters.
This winter, after mating season is over, the bucks will lose their antlers. In early spring, long before the fawns are born, the new antlers will begin to grow. The annual cycle continues.
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Eliza Howell Nature Walk 