Category: In the Field

I got the nest box monitoring team to stand in one place long enough for Rob to take a group photo.

From my most recent report of the nest box team’s activities:

Lots of activity in the past two weeks! We have nests in 8 of the 16 boxes we are monitoring. We have often observed mixed clutches of Wood Duck and Hooded Merganser, but [we] found something new in box #60: two birds flushed from the box, one of each species. The box has a combined clutch of 14 eggs.

We expect box #67 to be hatched out by May. Box #6 did not show any change between the 29th and the 5th, so it’s possible that this nest has been abandoned. Continuing my run of dropping hardware into the wetland, box #7 needs a new quick link closure: I have some spares and I will take care of this next time.

I have new GPS coordinates for all the boxes, and I will be distributing that info.

We have several pictures of duck and merg eggs side by side for comparison, and I will get something distributed shortly.

Tree Swallows say thank you to box #84 for being such nice spot to perch up on. A Brown-headed Cowbird could be heard in the parking lot on the 29th. An Osprey was fishing in the main pond on the 5th.

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That’s all for us for April. Our May work day will be the first Sunday, 3 May.

The team faced down the sleety weather this morning to start the rounds of checking nest boxes.

Following such a cold February, the wetland was substantially iced over, with only the main channel of Barnyard Run free-flowing. Which meant two things: first, we got some closer looks at wintering ducks than we otherwise might have.

Second, the effort of walking up to the boxes was much easier. Most of the boxes were surrounded by firm ice (see guest photo by Kat). This also meant that we weren’t working over our heads—always a challenge for the more diminutive members of the team. It was only at the edges of open water where the ice would suddenly break through, threatening to tip the unwary monitor into the cold, cold water and mud.

The end result is that we made our tour in an hour and half No dawdling to look for birds (though we did see a Bald Eagle and a couple of Pileated Woodpeckers), no fussing with the hardware. Back to the cars before the next round of frozen stuff falls from the sky.

What we did not see, somewhat surprisingly, were any merganser eggs. Usually they get a least one box started ahead of us, somewhere in the last days of February.

This windthrown maple is having a bad winter.

Sunday was my last visit to Ellanor C. Lawrence Park, at least for the purposes of the class project. I pulled off a couple of sections of the dessicated fruiting body of my Chicken of the Woods specimen to see the remnants of the pore surfaces underneath.

One of the tools we used in the course of the class was a rough-and-ready estimate of a tree’s age, given a measurement of its diameter at breast height (DBH). Now, it’s pretty clear from the landscape (as well as what we know about the general history of the region) that the park was once a farm. I don’t have enough information to determine whether this 40 acres or so that I’ve been studying was cleared for pasture, row crops, or what have you—no matter. But we can read some of the history of the land in its current trees.

Along the stone fence line, I found the oldest trees in the patch, White Oaks about 150 years old. Away from the fence, I found Black Cherry and Red Maple trees not much younger, maybe 135 years old. So these trees germinated during the period 1864 to 1871, give or take. And this observation fits with the historical record: Centreville, Virginia was a crossroads of fighting and encampment during the Civil War, especially 1862-1862. In the first half of the 1860s, every tree on the old Walney farm would have been cut down: you’ll find nothing older here.

We can go further. I see another cohort of trees: an American Sycamore about 78 years old, a Black Walnut of 80, a Tuliptree a bit older at 89 years old. These trees would have been seedlings about 1930, sprouting in old fields ready to undergo succession. The brief history provided by the FCPA web site admits that information about when the fields were abandoned is sketchy, but it would have been some time before 1935, when the farm was sold to Ellanor Campbell Lawrence for a summer place.

Sunday I spent most of my time in the park measuring mature trees to estimate their ages. I was surprised to find 90-year-old Red Oaks and Tuliptrees, which would indicate that this patch was no longer farmed as of about 1925. I also found a small outcrop of bedrock—I’m still trying to puzzle out the geology map to understand exactly what this rock is.

I’ve spent so much interest on this bloom of Chicken of the Woods, but not on the tree that it’s growing on. It turns out that it was a substantial Black Cherry (Prunus serotina), now deadfall. You can see the dark red wood, somewhat weathered, in the image. The tree had fallen across the trail; park managers would have sawed it into several large chunks, stretching through the woods toward the east and the housing subdivision. The chunks form a line about 100 feet long and end in a tangle of former canopy branches. This was a big tree.

Third and final trip with Joe and Stephanie, this time to forests of the Coastal Plain in P.G. and A.A. Counties.

First, we stopped at Watkins Regional Park, a mile or two from Central Avenue. The park is host to some humungoid old-growth trees: a Sweetgum the size of a Red Oak, a White Oak with a circumference of 152 inches at breast height that we estimated to be 242 years old. So what did I get a good image of? This lovely Round-lobed Hepatica (Hepatica americana) (a new plant for me), beginning to hunker down for the winter.

Nature fun analogy of the trip: the branches of a Pawpaw (Asimina triloba), bare of leaves, look like an old school VHF TV antenna.

Then, east over the Patuxent River and on to the Parris Glendening Nature Preserve, where we chased butterflies two springs ago. Geologically speaking, here the early Eocene Nanjemoy Formation lies above the Marlboro Clay. While the profusion of River Birch (Betula nigra) on the clay-based bits of the Preserve is quite nice, it’s the sandy passages, residues of the overlying Calvert Formation, that are really interesting. The trees are a near-monoculture of Virginia Pine (Pinus virginiana), but down at the herb layer we have the lichen Cladina subtenuis (at left), one of the so-called “reindeer mosses.” Recent rains led to a bloom of brittlegill mushrooms (Russula sp.) (at right).

Lying below the Nanjemoy is the Aquia Formation. This Paleocene unit of sand crops out to the west of Anne Arundel County, in Prince George’s County, where it makes a recharge zone. In A.A., now deep under other geologic formations, the Aquia constitutes an aquifer.

Back to the park this past Saturday, on a rather cloudy and breezy afternoon, with Leta riding shotgun this time. Many of the trees’ leaves are down; the unexpected Partridgeberry is still holding on to some fruits. The persimmon tree at the wineberry bench was holding some of its fruits, but I found lots on the ground, too. We gave them a taste, and the consensus is that while the pulp is okay, the pucker of a little bit of persimmon skin goes a long way.

We found a somewhat ratty example of Daedalea quercina on a dead branch.

I got out to the park not long after sunup today, so the birding was much better. White-throated Sparrows have definitely moved into the neighborhood for the season.


The Chicken of the Woods fruiting bodies on this log continue to fade and deteriorate. The image at left was taken twelve days ago; that on the right is from today.


I found an interesting dead branch that was full of boring insect galleries. No guesses as to what sort of beetle is responsible.

Joe and Stephanie led the class to several sites of Piedmont forests in Montgomery County, including one patch that I had never visited. Along the Seneca Creek Greenway Trail, there’s contact between the sedimentary rocks that filled in the Culpeper Basin and the crystalline rocks of the Marburg Schist. That’s an opportunity for groundwater to collect, and therefore you can find some tree species that like their feet wet in this otherwise upland locale. Best example: this humongous Box Elder (Acer negundo), found along the remnants of a hedgerow.

Down along the Potomac at Riley’s Lock, where that same Seneca Creek has its mouth, is a handsome row of salmon-skinned River Birch (Betula nigra) (left), as well as single trees of Black Walnut (Juglans nigra) (right), soaring into the sky.

We talked about mnemonics and keys for separating the white oak and red oak groups. The acorns of the reds, somewhat like red wines, are more acidic and require some aging underground before they germinate (or become palatable to squirrels). The bristle tip on the leaf of a red oak is not a separate structure, but rather an extension of the leaf vein. Even a red oak-group Willow Oak (Quercus phellos) shows a small bristle tip. White or red, a dry oak leaf takes a long time to decompose; thus, “an oak forest is a noisy forest.”