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American Kestrels Return to our Stroud Preserve

By Mike Coll, preserve manager

American Kestrel, Ron ZiglerThis year for the first time the walking trail through the “Bobolink Meadow” at our Stroud Preserve was closed to foot traffic during bird breeding season (April-August). This trail closure is one of a number of such closures aimed at protecting the breeding grounds of sensitive bird species. In this case the impetus for closing the trail was the breeding population of Bobolinks, a species that consistently nests in the grasses of this particular meadow. These ground-nesting birds can be negatively impacted by the proximity of humans and dogs (especially unleashed ones).

However, closing the trail appears to also have had a positive impact on another species in decline, the American Kestrel. Kestrels are also easily disturbed by humans and, although a box had been present for a number of years, I had never observed Kestrels nesting there until this year. The trail previously came almost directly beneath the box and likely was the reason they hadn’t used it.

Here is a video of the young birds (looks like 4) at just a few weeks old:

The Milkweeds and Their Little Buddy

By Russell Rogers, volunteer at Stroud Preserve

Red milkweed beetle

Mid-summer is upon us and with it are the milkweeds. Ever since I can remember I have had a fascination with milkweeds. They are most often large and showy, and in my opinion their flowers are amongst the most visually interesting flowers that can be found around here. The petals are flexed backwards as far as they can go, while the rest of the flower, the parts that most other plants keep hidden, is thrust forward into space. This gives it the appearance that the flower bud exploded and then was frozen in time right as it was about to fly into pieces. To add to its strange appearance, the parts of the flower that are extended forward are unique in that they consist of hoods and horns. It truly has the appearance of something from another world.

Poke milkweed by Russell Rogers

Poke milkweed showing the hoods and horns

Milkweeds can afford to be showy as their milky sap is poisonous to most animals. Insects that feed on the plant are also brightly colored. A statement to the effect of “look, but don’t eat.” A well-known example of an insect that feeds on milkweed is the caterpillar of the monarch butterfly. However, the insect that caught my eye was a little red and black longhorn beetle called Tetraopes tetrophothalmus, or simply the red milkweed beetle. They are interesting in of themselves as the antennae completely bisects their eyes, creating two sets of compound eyes. Thus the name Tetra “four” opes “eyes.”

As an ecologist I try to make observations of the natural world without injecting my own biases and assumptions. That said, my assumption about the milkweed and its little buddy, as I call it, was that they held some type of symbiotic relationship. Symbiotic meaning that they benefit from each other’s presence.

A little research showed that there may, in fact, be a symbiotic relationship, albeit, not between the beetle and the milkweed, but instead, between the beetle and the grasses that grow next to the milkweeds. As it turns out, the beetles only lay their eggs on the stems of dried grasses that grow immediately adjacent to the milkweed plant. The eggs hatch and the larvae drop off and burrow into the soil where they feed only on the roots of the milkweed plant. The larvae pupate in to adult beetles and continue to feed on the milkweed. All of this feeding upon the milkweed by the beetle ultimately inhibits the milkweed’s growth, in turn making more room for grasses to grow.

While the sap of the milkweed plant can be a culinary hazard, the nectar is not and attracts a wide assortment of butterflies and other interesting insects. If you would like to see these strange and wonderful plants and the insects that they attract, the Stroud Preserve is a great place to do so as there are at least five species of milkweeds that call the preserve home. Look for the poke milkweed (Asclepias exaltata) pictured above in moist shaded woods. Swamp milkweed (A. incarnata), common milkweed (A. syriaca), and butterfly-weed (A. tuberosa) can be found in the open fields throughout the preserve. Lastly, look for the rare whorled milkweed (A. verticillata) in and around the serpentine barrens. (The whorled milkweed is quite common at the Willisbrook Preserve, near Malvern).

Swamp milkweed (Asclepias incarnata) by Russell Rogers

Swamp milkweed (Asclepias incarnata)

 

Common milkweed (Asclepias syriaca) by Russell Rogers

Common milkweed (Asclepias syriaca)

 

Butterfly-weed (Asclepias tuberosa)] by Russell Rogers

Butterfly-weed (Asclepias tuberosa)

 

Whorled milkweed (Asclepias verticillata) by Russell Rogers

Whorled milkweed (Asclepias verticillata)

Stroud Preserve: Ferns

By Russell Rogers, Stroud volunteer

Spring is a time when most people look forward to seeing the explosion of colors of all the wildflowers and songbirds of our area. One look at a singing Yellow Warbler or a hillside full of Virginia bluebells, and the gray doldrums of our long winters suddenly become a distant memory. One reason these vibrantly colored elements of our countryside stand out so well is that they are cast against a sea of green. With so many brightly colored things to catch our eye this time of year, it can be easy to look past the vast variety of trees, grasses, sedges and ferns that serve as their background.

Ferns, and their allies, including horsetails, adder’s tongue and royal ferns, are an incredibly diverse group of plants found in just about every habitat type in Pennsylvania. The Stroud Preserve is a great place to see many of these, most of which are easily viewable from the preserves many trails.

From the Creek Road parking lot it is a very short walk to what is probably the preserve’s most strange and interesting fern, the Purple cliffbrake. It can be found growing on the stone walls of the bridge that goes over the East Fork of Brandywine Creek.

Pellaea atropurpurea

Purple cliffbrake Pellaea atropurpurea (L.) Link

This fern is fairly uncommon and found only in the eastern portion of the state. Ferns, having neither flowers nor seeds, reproduce via spores that are held and released from the underside of a fern’s leaves. Only some of a fern’s leaves carry the spores. At first glance, it is difficult to tell which of a fern’s fronds bear the spore-producing leaves (“fertile” leaves/fronds), and which fronds are non-spore-producing (“sterile”). The Purple cliffbrake’s fertile and sterile leaves, however, are so different in shape and color that, if it weren’t for their proximity to each other, you would think the fronds belonged to separate plants. That is to say, Purple cliffbrake exhibits “frond dimorphism”. The Purple cliffbrake prefers limestone cliffs and other rocky outcrops and, occasionally, the stone walls of old barns and bridges. It is also unusual in the way of ferns because its fronds are evergreen and can be seen on the bridge year round.

Keep walking west down the road over the bridge, and on the right you will see a creek that has a large population of Sensitive ferns.

Onoclea sensibilis

Sensitive fern Onoclea sensibilis L.

Some people assume that, because of their name, they fold up like a Venus flytrap when you touch them, and that would be a truly remarkable thing if it were true. Unfortunately, it is not. In fact, it gets its name because it is sensitive to extremes in temperature. In the cold snap that we had the other week, these ferns lived up to their name –the following day, the new fronds were brown and shriveled up.

From here, choose any of the preserve’s trails through the woodlands, and you will almost certainly see Christmas and Lady ferns. They are by far the most commonly encountered ferns in the preserve. Like the Cliffbrake, the Christmas fern is green all year long. In contrast to the thick leathery leaves of the Christmas fern, the leaves of Lady ferns are light and wispy, indicating their ephemeral nature.      Polystichum acrostichoides                                 Christmas fern Polystichum acrostichoides

Athyrium filix-femina

Lady fern Athyrium filix-femina

Be sure also to keep an eye out for some of the lesser known and harder to find ferns like Rattlesnake fern, Long beech fern, and Evergreen wood-fern, all of which can be seen within several feet of the preserves trails.

Botrychium virginianumDryopteris intermediaPhegopteris connectillis

Rattlesnake fern                Long beech fern                Evergreen wood-fern

If you make your way around to the serpentine outcrop on the north side of the preserve, look closely in between the cracks in the rocks and you will see a few ebony spleenworts, one of the few ferns that can tolerate the serpentine environment. Lastly, don’t forget to take a broader look around. You might even see a vivid pink of a wild geranium or the neon orange of a Baltimore Oriole!

Asplenium platyneuron

Ebony spleenwort Asplenium platyneuron (L.) Britton, Stearns & Poggenb.

National Trails Day Hike at Stroud Preserve

Saturday, June 2
10:00 AM
Stroud Preserve, West Chester, PA

Get to know Stroud Preserve with Natural Lands Trust!

Stroud Trail Ambassador Brian Delphus will lead a guided hike of Stroud Preserve. Meet at the Stroud Preserve parking area off of North Creek Road.

Bring water and sturdy walking shoes. This event is rain or shine but we will cancel in case of downpour.

Free and open to the public. No preregistration required. For more information please contact Angela at (610) 353-5587, ext. 266 or .

Stroud Preserve Walk – White Oak Society and Allston Jenkins Legacy Society members only

Wednesday, May 30
10:00 am – 1:00pm
Stroud Preserve, West Chester, PA

A lovely mosaic of woodlands and meadows, the 574-acre Stroud Preserve is an excellent example of the rolling farmland that once dominated the Chester County landscape. With local birder and Stroud volunteer Jim McVoy and preserve manager Fred Gender, we’ll spend time in the meadows observing the gregarious bobolinks, one of our favorite harbingers of spring, and then enjoy a hike in the woods. Following we’ll gather in the shade for light refreshments. Participants are encouraged to bring a brown bag lunch.

Click to learn more about the White Oak Society and Allston Jenkins Legacy Society.

Please RSVP to Suzanne Barton 610.353.5640 ext 313, .

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