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.

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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.

Blue-gray Gnatcatcher Nest: An Annual Quest

This is the eight consecutive year that I have found at least one Blue-gray Gnatcatcher nest in Eliza Howell Park. The nests are small, not easy to find, and I am fascinated by them, thrilled when I find one.

This 2019 nest (in the center of the picture) is in a maple tree, lower than many.

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The Blue-gray Gnatcatcher is a very small and very active bird with a longish white-edged tail. It winters in (or near) Central America and arrives in EHP in April each year.

     Photos 2, 3, and 5 are by Margaret Weber.

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By the middle of May, pairs are making their nests, the female and male working cooperatively on a neat, 2-3 inch-wide (outside dimensions) open cup placed on a horizontal branch, often next to a vertical or side branch.

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The nest is as tall as it is wide, flexible layers of material like grasses and strips of bark all held together and attached to the tree by spider webs or caterpillar silk. The outside is almost entirely covered with lichen and bark flakes, making it look more like part of the tree than like a bird nest. The camouflage is effective; even when I know where the nest is, I often have a hard time re-locating it.

This is one of my favorites among the nests I anticipate seeing annually. I am fascinated by the way in which the outside is “decorated,” and by the webbing used to attach it (some of which is visible in this picture).

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The approximately 1.5 inch-wide inside is lined with soft plant down. It is tiny, but big enough for 3-5 eggs/nestlings. The eggs are only 1/2 inch long. Both sexes participate in incubation and in feeding the young, just as they do in nest building. They sometimes have a second brood (in a different nest) a little later and they will build a second nest if, for some reason, they abandon the first one.

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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.

Note: This year the field trip is on Saturday, June 8, beginning at 8:00 a.m. Everyone is welcome.

 

Cardinal Nest Watch

The watch started on April 26, when I noticed a female Northern Cardinal carrying a twig into a small bush in Eliza Howell Park. Cardinals usually have two broods a year and April is the normal time for the first in southeast Michigan.

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Photo by Margaret Weber

The closer look I took when she flew away showed a partially constructed nest. By April 28, the next looked finished or very nearly finished.

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Cardinals usually hide their nests in dense plant growth and in locations where they cannot be seen or watched from any distance. This one is quite well camouflaged, but it is low and visible (especially when using binoculars) on one side from about 30 feet. I immediately thought that this is a nest that I might be able to watch without disturbing the birds.

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The female Cardinal lays one a day until there are 3 – 5 eggs. And, like many birds, it doesn’t start incubating them until the clutch is (nearly) complete. This results in the eggs all hatching at nearly the same time.

On April 30, there was no bird present, so I approached the nest: 1 egg. On May 1: 2 eggs. On May 2: 3 eggs.

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Starting on May 3, the female has been on the nest every time I looked, so I have kept some distance and have not been able to discover the full clutch size.

Among cardinals, the female does all the brooding, while the male is nearby and feeds her from time to time (I have not yet seen him feeding her at this location).

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Photo by Margaret Weber

Cardinal eggs hatch after 11 – 13 days incubation, so I expect the next big development to be about May 14 – 16, if all goes well. Then both parents feed the young for about 10 days.

One of the questions I have is whether a Brown-headed Cowbird has laid an egg in the cardinal nest (and possibly displaced one of the cardinal eggs). Cowbirds are brood parasites, laying eggs in the nests of other birds for incubation and feeding. Another cardinal nest I checked this year contained three cardinal eggs and one cowbird egg.

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Not all nests lead to the successful fledging of young. There are a variety of reasons for nests to fail, so I will be watching to see whether the nest is destroyed or abandoned, how many eggs hatch, how many nestlings fledge, and whatever else I might observe.

The location is one that makes it easier for me to watch this nest than others that I have found, but it seems a risky location, more vulnerable to predators. But it was selected by the pair together, without requesting my opinion, so I will  simply continue to enjoy my opportunity to nest watch!

 

Chickadees Are Not Woodpeckers, but…

I have lingered many times during my walks in Eliza Howell Park during the last eight days to watch a pair of Black-capped Chickadees as they excavate a nesting cavity in a small broken-off dead tree.

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Photo by Margaret Weber

Chickadees are cavity nesters who sometimes select an already existing cavity and sometimes dig their own. When they excavate a new hole, they often try several locations before they settle on one. (Last year they started in one location and then moved; see my post, “Chickadee Nesting Discernment,” May 4, 2018). So I was pleased and excited when it became clear that they were proceeding with this one.

Chickadees do not have the beak and head perfected for hitting wood repeatedly, as woodpeckers have. But, in the right conditions, they get the job done.

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Photo by Margaret Weber

Woodpeckers usually drill their nesting holes in dead trees, but in wood that is solid, not yet rotten. Chickadees, on the other hand, select a snag (standing dead tree) or a stump that is starting to decay. Once they get through the surface, their excavating is not so much chipping away at the wood as it is pulling the soft wood apart. In the first picture above, the bird emerged with a full beak only 3 or 4 seconds after entering the hole.

The snag they are using this year is the small slanting tree in the next picture. The hole is about 10-12 feet high. The fungi on the tree suggest that the tree has been dead for some time.

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As is usually the case in locating nests, I found the spot by watching where the bird went. The hole was about 1 ½ inches deep when I first saw it.

Two features of chickadee nest-making are worth noting.

  1. They often select a location on the snag that is somewhat protected from the weather. Here, the hole is made on the “underside” of the slanting tree (the left side as we look at this picture), where rain is less likely to enter.
  2. When woodpeckers excavate, they bring the chips to the entrance and “spit” or drop them out there. Chickadees, on the other hand, carry their excavated material 10 or more feet away from the nest before dropping, using a couple different locations. Thus, there is no base-of-the-tree clue to a predator that there is nest above.

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Photo by Margaret Weber

Chickadees dig a bowl-shaped hole about 8 inches deep before nesting. In a tree this size, that means that they will hollow out most of the inside. This drawing, from the naturalist Bernd Heinrich (The Homing Instinct, 2014), helps to show the size and explain why they are still excavating in the second week after they began.

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Both female and male excavate, but they will divide tasks in the next phases. The female will make a nest of soft material in the cavity, lay (probably) 6 eggs, and incubate them. While she is incubating, the male will feed her.

I hope to be able to observe some or much of what comes next, but for now I feel privileged to have been able to watch the first step in their nesting.

Mallard: First among Dabblers

The many duck species found in North America are sometimes described as either “diving ducks” or “dabbling ducks.” During recent March walks along the river in Eliza Howell Park, I have been watching the best known of all dabbling ducks, the Mallard.

At this time of the year, Mallards are usually seen as a female-male pair.

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         Note: All bird photos included here are courtesy of Margaret Weber.

“Divers” forage for food by diving and swimming under water, while “dabblers” are surface feeders; they sometimes put their heads under water but do not submerge to seek food. Dabblers like shallow water and are also referred to as “puddle ducks.” They also feed on land at times.

In Eliza Howell, they are most commonly found on the river but are sometimes seen in the toad breeding pond in the spring (before the pond goes dry). And they are sometimes found even in a flooded roadway. In this picture, a female is surface feeding.

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Mallards are present all year, whenever there is ice-free water (I have seen them in 11 of the last 15 Januaries). Outside of the breeding season, they often congregate in small flocks.

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It seems fitting to refer to Mallards as first among dabblers for a number of reasons. They are the most common and most familiar duck, found throughout North America and Eurasia. They are the biological ancestor of almost all domesticated ducks. The Mallard is both widely hunted as a wild duck and at home in many parks.

The “quack” that most of us tend to associate with ducks in general is the sound of the female Mallard (the male vocalizes differently) and the Mallard is the first duck that many of us encounter in our lives. The picture that often comes to mind when we think of a native wild “duck” is that of the green-headed male Mallard.

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As is common among ducks, the female incubates the eggs and cares for the young entirely on her own. Her colors make it very difficult for a predator to spot her when she is on the nest half covered by the dead grasses and leaves that remain from the previous year.

Mallards nest in Eliza Howell and I occasionally find a nest – always by surprise when I happen to get so close to a hidden nest that the bird flies out. The females lay about 12 eggs (usually one a day) and incubate for about 28 days after all the eggs are laid. The young are ready to leave the nest about a day after hatching and follow the mother to water, where one of the annual joys of bird watchers is observing several young swimming behind a Mallard mother.

When I came across this nest as the hen flew out, it looked like egg-laying was still in process and she had just added an egg to an incomplete clutch.

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Mallards have lived in proximity with humans for centuries and in some parks, especially where they are fed by park visitors, they are quite “tame.” Those in Eliza Howell are in a more natural setting. They are almost always present, however, and provide an opportunity for visitors to observe their behavior.