Caddo Oak

Yesterday I spent an hour and a half at Sheri Capehart Nature Preserve on a spring afternoon full of wonderful things. I wrote the following at the Friends of Sheri Capehart Nature Preserve blog, and I hope you’ll go visit there. But meanwhile I have reproduced it below.

March 13, 2026 – Clear sky, breezy, and temperature in the mid-70s at 3:00pm.

I’m starting to think of spring as beginning when March arrives, as opposed to the more official date of March 20th. Trees are leafing out and flowers are popping up like the delightful crowpoison, which grows from a bulb and looks a little like wild onion but is not. The Lady Bird Johnson Wildflower Center says, “Some references list this species as poisonous to humans. The jury is still out about its toxicity to crows.” That part about toxicity to crows sounds a little tongue-in-cheek, but it makes for a fascinating name for the plant.

*A mournful thyris visiting a cluster of crowpoison flowers*

The flowers were visited by several small mournful thyris moths. These are black-and-white moths that fly during the day early in the year and reportedly just for a few weeks. It’s another species with a name that makes me want to find the story, but so far I have not found a reason for it to be mournful. Even its species name makes me curious (Pseudothyris sepulchralis, where “sepulchralis” seems to refer to a sepulchre, that is, a tomb carved in rock).

Meanwhile at the north pond, dragonflies were flying and turtles were basking in sunshine, including a pair of red-eared-sliders sharing a small branch of wood at the water’s surface. Those pond turtles are active even on warmer winter days, but spring sunshine makes them seem very content – though that is a perception from a human point of view that could be completely off-base.

I tried to capture the overall look of the woodland in a photo that, seen on a phone’s little screen, is probably very plain. But the crowns of trees are covered in a sort of mist of pale green, the budding of new leaves and the catkins of the oaks. I checked to be sure of the details because I’m not a botanist or even a knowledgeable plant person, but catkins are the dangling strings of the male flowers of oaks. They will be releasing the yellow pollen that coats your windshields, sidewalks, and noses in the coming weeks. And with any luck, they find their way to the female flowers on the oak trees, which are much less conspicuous.

*New blackjack leaves – notice the spines at the end of each leaf lobe*

The other thing that always seems wonderful to me is how the blackjack oak leaves come in as little red leaves, then turn such a wonderful deep green later on, and next autumn may once again be red – or yellow or some combination – before dropping to the ground.

*Blunt woodsia growing in a protected spot along with some moss*

Along the north side of the woodland, where it meets the patch of prairie, there are shaded spots and little embankments where the land moves up toward the top of the hill. In one of those shaded places I saw a fern that you can find around the hillside and up toward the bluff. It is the blunt woodsia, also called by a couple of other common names like blunt-lobed woodsia. Finding these little ferns, or the various mosses or even liverworts, brings you to a different perspective, like looking at tiny worlds existing in the shaded places in the preserve where moisture is not too scarce.

*The grand old post oak designated as the Caddo oak, after the Caddo people who once lived in the area*

I walked by the Caddo oak, a huge post oak designated as a historic tree by the Texas Historic Tree Coalition, and its crown is speckled with new green leaves, just as it has done every year for roughly 200 years.

Nearby, I watched a medium to large bird sail through trees and across a part of the north prairie, disappearing into understory and trees to the west. I immediately thought of the northern harrier, a graceful hawk that tends to hunt on the wing, flying low and listening for rodent movement. This bird had the right shape and the kind of flight I would expect with a harrier, and I saw that this brownish bird had some white markings but I could not spot the white band that should go across the base of the tail. So I just don’t know. I noticed that Brent Franklin saw one here at the preserve in 2018, which helps make it plausible, but of course doesn’t confirm my observation today.

Walking around the blue loop, I saw a couple of mourning doves near the boulder trail. They were behind a sort of thicket and did not seem perturbed by me and my camera about twenty feet away. They were probably foraging for seeds along the ground.

*Texas spiny lizard, watching me carefully*

On the way down the south-facing hill, glint of reflected sunlight caught my eye. It turned out to be reflected off the back of a male Texas spiny lizard clinging to a small tree trunk. He eyed me in that way that these common lizards do, making his best guess about whether to remain motionless and hopefully unseen, or quickly scurry around to the other side of the trunk. After I took a photo as I moved around him slowly and hoped not to scare him, he quickly scooted around the trunk and out of sight.

It was certainly a walk full of wonderful things today. Everywhere I went there was butterfly and moth activity, either more of the mournful thyris moths or else goatweed leafwings, sulphurs, or a swallowtail or two. And the southern dewberries are blooming with those beautiful white flowers.

*Southern dewberry, which will feed birds and other wildlife later in the year*

As I started on the trail this morning at Sheri Capehart Nature Preserve, I asked permission, so to speak. I said: “May I be here as one among many, neither greater nor less than. May I understand how I fit within this place and cause no harm.”

I expected no particular answer, but I did hear calls of Bewick’s Wren, Northern Cardinal, Red-bellied Woodpecker, Blue Jay, and Painted Bunting (identified by the Merlin app), and those calls felt welcoming. Low clouds covered most of the sky, and it was a little like being draped in a warm, wet blanket. Weather Underground said it was 81F and 76% humidity in the area.

On the trail I was submerged beneath the green canopies of oak trees and then emerged at a little open hillside where the spring rains are helping the Little Bluestem grasses look like they might take back the slope that has suffered erosion and drought.

At the pond, the roster of bird calls expanded to include White-eyed Vireo, Carolina Wren, and Carolina Chickadee. And while the Black Willows have taken over large sections of the bank, in one spot there was a beautiful patch of flowers. Chickory, Black-eyed Susan, and Bitterweed were scattered in different shades of yellow. And as I looked out over the water, a group of Blanchard’s Cricket Frogs set up a chorus of “grick-grick-grick” calls. Those calls are always surprisingly loud for a little frog that could easily sit on your thumb.

*An Eastern Pondhawk. Females of this species are bright green while males are blue*

I climbed uphill and away from the pond and walked upslope along the north prairie. Every part of this walk brought wonderful things into view, including Glen Rose Yuccas retaining some of their flowers, a few Indian Paintbrush among the grasses and Western Ragweed, Silverleaf Nightshade (a nettle with a beautiful name and lovely lavender flowers), and Texas Bull Nettle growing tall with their big leaves and white flowers.

And that brought me to the Old Man (Old Woman, if you like) of the preserve, a huge Post Oak that the Texas Tree Coalition designated as a Historic Texas Tree in 2019. It is called the “Caddo Oak,” in honor of the Caddo People who once lived here. After more than 200 years it continues to stand, with a huge trunk and massive branches stretching out like arms to embrace the sky.

This “Old Person” – oak trees have both male and female flowers so I shouldn’t assign them a gender – might give us a sense of a something ancient that presides over the place. There are a few other big oaks on the preserve, but probably none that were growing when Texas was part of Mexico, before independence or the battle at the Alamo. We are fortunate that it is still here, never in all those years cut down or burned.

From there I followed the trail as it turned south, taking me to where I could visit the yucca meadow, a big patch of deep, soft sand that supports Glen Rose Yucca, Lanceleaf Blanketflower, and other low plants. Some of the yuccas still had their flowers, though the cycle in which Yucca Moths pollinate the plant and lay eggs where the larvae will then eat some of the developing seeds (not too many) is probably winding down. That meadow is also home to the Comanche Harvester Ant, a species of what Texans call “big red ants” but this one requires deep sandy habitat with nearby oaks, and this limits where they may be found.

*The yucca meadow (I took this photo on May 8th)*

Continuing around the preserve, I found a tiny juvenile bush katydid with black-and-white banded antennae on the flower of a Lanceleaf Blanketflower, and then a Six-spotted Flower Longhorn Beetle crawling over a Black-eyed Susan flower. On a walk like this, the insects provide so many fascinating forms and colors.

I arrived within the woodland at the crown of the hill, and the clouds had broken up so that there was bright sunshine and lower humidity. At 11:20am I lay on my back and watched the low fragments of cloud drifting swiftly to the north. At the ground there was a good breeze. A Tiger Swallowtail fluttered through the area, perhaps visiting the Standing Cypress that are scattered wherever there is a small opening in the oak woods.

And the Standing Cypress is having such an amazing year at the preserve. You first see them in winter, growing as a delicate rosette of thin, fern-like leaves. But in spring the plant sends up a tall stem that can grow up to six feet, with a flower spike at the top that produces clusters of red, tubular flowers.

It was over two hours of delight, despite that warm blanket of humidity. After the first hour I was pretty well adapted anyway, or else all the wonderful stuff outweighed any discomfort. We are all lucky to be able to go and be part of this wild piece of Arlington.

Our Lives In Nature

How nature supports, informs, and inspires our lives

A Spring Journal Entry from Sheri Capehart Nature Preserve

Drenched In Humidity and Birdsong