We humans love to be near water, so much so that we build water features where they didn’t exist. We make backyard ponds, scenic ponds, and improve streams.
Garden pond (photo from Wikimedia Commons)Panther Hollow Lake, Schenley Park, March 2024 (photo by Kate St. John)Construction at Phipps Run, Schenley Park, 20 Nov 2021 (photo by Kate St. John)
All along I’ve suspected that these water features, though often beautiful, are not nearly as good as what nature creates. And now we know for sure.
Two studies find that beaver-engineered wetlands attract twice as many hoverflies, nearly 50% more butterflies, and a richer variety of bats compared to human-made ponds or free-flowing streams.
Now that most of the trees are bare(*) we can see nests that were hidden by summer leaves. Among them are those built by hornets, birds, and squirrels.
Papery hornet nests dangle like hanging raindrops or upside-down cones from a sturdy branch.
Squirrel nests — actually called dreys — look like misshapen leaf balls with a few twigs poking out.
A drey is the nest of a tree squirrel, flying squirrel or ringtail possum (in Australia). Dreys are usually built of twigs, dry leaves, and grass, and typically assembled in the forks of a tall tree. They are sometimes referred to as “drey nests” to distinguish them from squirrel “cavity nests” (also termed “dens”).
Squirrels use dreys as nests in spring-summer and shelters in the winter. Before the leaves fall they are busy biting off leafy branches and carrying them up to the winter drey. It takes a lot of effort to keep their shelter warm and waterproof. Brrrr!
In the top photo there are three dreys in three trees and one in the fork of a tree in Schenley Park, below.
Squirrel drey in the crotch of a tree, Schenley, 11 Dec 2016 (photo by Kate St. John)
How can we tell whether it’s a squirrel’s drey or a large bird nest?
Large bird nests, such as the crow nest below, are built of sticks. Squirrels use leaves, especially on the outside.
(*) Most of the trees are bare: For many years I’ve kept track of leaf-off in Schenley Park. Sometimes it’s early, sometimes it’s late. This year most of the trees were bare on or before Friday 14 November 2025. Here’s what the park looked like on that date.
Most of the trees are bare, Schenley Park, 14 Nov 2025 (photo by Kate St. John)
By November adult orb weaver spiders have died and left behind overwintering egg sacs to hatch in early spring. The zigzag webs are gone but there is new scientific research about their purpose. Why do these round, almost invisible webs of Argiope spiders have thick prominent zigzags on them?
The zigzag web decorations are called stabilimenta, a word whose Latin origin means “stabilizer.” Unproven past theories on their purpose include:
For stability? No. The decorations are only loosely attached to the web.
To camouflage the spider?
To draw notice to the web so large animals don’t break it?
To attract prey by reflecting UV light?
To attract a male?
An October 29 study in the journal PLOS Oneoffers yet another explanation. Instead of stabilizing the spider web’s structure, the filaments help out spiders by allowing the vibrations of a stuck animal to disperse throughout the entire web, the research found. This in turn helps the spider know exactly where its prey is on the web structure, they write.
To reach this conclusion, scientists created computer simulations of prey hitting Argiope bruennichi spider webs based on photographs of the stabilimenta. They concluded that when prey hit the web at a tangent the stabilimenta amplified prey vibrations throughout the web. This might help the spider find the prey.
Yellow garden spider wraps her prey, Sept 2017 (photo by Kate St.John)
But …”The actual impact of the stabilimenta may be limited, the researchers admit. For now, they write, the true reasons behind the spidery structures remain largely unknown, with many hypotheses still untested or lacking experimental validation.” — from Smithsonian Magazine.
Yellow garden spider female with prey, Sept 2017 (photo by Kate St.John)
Remember the brown marmorated stink bug invasion? Halyomorpha halys was first noticed in Allentown PA in 1998 and soon spread across the state. By 2010 alien stink bugs were causing record damage in Pennsylvania orchards and annoying homeowners by invading tiny cracks in our homes at the first sign of cold weather. October used to be the worst month for this.
Brown marmorated stink bug outside my window, August 2023 (photo by Kate St. John)
Studies back then predicted where the stink bug was likely to invade while USDA searched for a biological control. They were looking for a predator within the brown marmorated stink bug’s native range that would not pose a threat to North American species.
Meanwhile the stink bug continued to spread. Within 20 years it was thick in the I-95 Corridor, clearly established east of the Mississippi, and had spread in the Pacific coast states.
By 2018 researchers had settled on a safe non-stinging wasp, the Samurai wasp (Trissolcus japonicus), that lays its eggs inside brown marmorated stink bug eggs; its larva eats the egg from within. The map below shows the wasp’s potential range around the world. Its outlook as a solution in the eastern U.S. was great but it was marginal to unsuitable in the West.
Approvals to import the wasp were still grinding through the bureaucratic process when the Samurai wasp showed up on its own as described in this vintage article: Stinkbug Predator Shows Up On Its Own.
As soon as that happened the wasp became available to farmers in need of stink bug control and the wasp continued to spread naturally.
By 2021 it had spread to North Carolina and surprisingly to southwestern Idaho, a place that was mapped (above) as marginal-to-unsuitable habitat for the wasp.
But the wasp doesn’t care. There are stink bugs in Idaho so the wasp flew east out of Oregon and found a new home. This USDA map on the stopbmsb.org website shows the distribution of both species, the stink bug in solid colors, the wasp as dots.
Back here in Pennsylvania I rarely see brown marmorated stink bugs anymore, thanks to the female Samurai wasp who’s a great traveler in search of stink bug eggs.
p.s. I wonder how she finds the stink bugs. Can she smell them from afar?
UPDATE: See the comments! Some people still have stink bugs at home
Two weeks ago a monarch butterfly with a broken wing was brought to Sweetbriar Nature Center on Long Island where they have a butterfly house (vivarium) with a wide variety of species. The injured monarch could not fly and would surely die but the Nature Center’s Wildlife Rehabilitation Director, Janine Bendicksen, searched for a dead monarch butterfly in the vivarium and performed a wing transplant.
NOTE: The absence of roosting spots in the eastern U.S. does not necessarily mean they don’t exist. It may mean these roosts are not as noticeable in the forest compared to the Plains or that no one is reporting on them.
Inky cap mushrooms in mulch at Cathedral of Learning, 30 Sep 2025 (photo by Kate St. John)
4 October 2025
This week started with two signs of fall in Pittsburgh: Inky cap mushrooms melting into “ink” and a spider web beaded with fog.
Spider web in fog, Schenley Park, 28 Sep 2025 (photo by Kate St. John)
On Wednesday my husband and I traveled to Cape Cod for a family visit and a day-trip yesterday to Nantucket. The weather is gorgeous but has recently kept migrating birds away from the coast. Birding is quiet here compared to reports from friends in Pittsburgh.
View of Nantucket harbor, 3 Oct 2025 (photo by Kate St. John)
Cape Cod’s sandy soil and saltwater attracts plants we don’t have in western PA. My Picture This app said this is coastal sweetpepperbush (Clethra alnifolia). The shape of the fruits gives the plant its name though there is nothing peppery about it.
Costal sweetpepperbush, Bell’s Neck, Cape Cod, 2 Oct 2025 (photo by Kate St. John)
Yesterday a two-headed bee flew by and landed on the gravel where it was easy to figure out it was two bees conjoined: a future queen and a male. The queen is so large and strong that she can fly while he’s attached. The second photo looks fuzzy because they are vibrating.
Bumblebees mating, Nantucket town, 3 Oct 2025 (photo by Kate St. John)Bumblebees mating, Nantucket town, 3 Oct 2025 (photo by Kate St. John)
At home in Pittsburgh it feels like summer. Here on the Cape, surrounded by water, all the buildings have the heat on because the nights are cold.
Bumblebee on bluebeard, 23 Sept 2025 (photo by Kate St. John)
27 September 2025
Good morning.
Sunrise in Pittsburgh on 27 September 2025 (photo by Kate St. John)
After it rained on Monday I took a walk just before another rainstorm pelted the neighborhood. All the plants had been washed clean and a garden of bluebeard (Caryopteris sp.) was swarming with bumble and honey bees. Bluebeard is native to Asia but the bees don’t care.
Bees on bluebeard, 23 Sept 2025 (photo by Kate St. John)
Three days earlier, while birding in Frick Park, I noticed the amazing spikes standing up from the leaflet axils on Japanese angelica (Aralia elata).
Spines on Japanese angelica leaves, Frick Park, 20 Sept 2025 (photo by Kate St. John)
A closer look revealed that all the leaf veins had spikes down to the tiniest detail.
Closeup of spines on Japanese angelica leaves, Frick Park, 20 Sept 2025 (photo by Kate St. John)
How did I know this is the invasive alien Japanese angelica (Aralia elata) instead of the native devil’s walking stick (Aralia spinosa)? I didn’t, but it was a good assumption because of the plant’s location and the fact that even botanists were fooled by Aralia elata for a while.
See the range maps and how to tell the difference in the article below. Good luck!
Gabrielle Marsden releases a zebra swallowtail at Schenley Park, 31 August 2025 (photo by Kate St. John)
6 September 2025
This week I couldn’t help but notice the landscape looks very dry and plants are wilting.
Unwatered grass is brown in the drought, 2 September 2025 (photo by Kate St. John)Orange jewelweed at Schenley Park is wilting in the drought, 31 August 2025 (photo by Kate St. John)
And now it’s official. Pennsylvania is in a moderate drought in Elk, Cameron, northwest Clearfield, western Allegheny, Beaver and Greene counties. Notice the pink arrows I added to this map from U.S. Drought Monitor at UNL.
Gabrielle Marsden (@gobbism on Instagram) raises many kinds of butterflies, especially zebra swallowtails. She brought three adults to Schenley Park to release during the Botanical Society walk last Sunday. (See top photo) The butterflies’ host plant, the pawpaw tree, grows in Schenley.
Zebra swallowtails ready for release, 31 August 2025 (photo by Kate St. John)
Botanical Society of Western Pennsylvania walks focus on plants but the outings do not ignore the rest of nature. Bugs are often associated with specific plants so when we found cool bugs we took a look … and found a planthopper. He was easy to see because his bright green disguise doesn’t work in a drought.
Planthopper is too gren for the drought.
We also found the remnants of a scissor-grinder cicada who left his exoskeleton behind on a leaf.
Scissor-grinder cicada exoskeleton, Schenley Park, 31 Aug 2025 (photo by Kate St. John)
Sometimes the bugs found us. Steve Tirone had to stop in his tracks to avoid hurting the katydid on his shoe.
Katydid on Steve’s shoe, Schenley Park, 31 Aug 2025 (photo by Kate St. John)
p.s. I forgot to tell you what we saw on the Schenley Park outing last Sunday, 31 August.
Schenley Park outing, 31 August 2025 (photo by Kate St. John)
The birds were quiet and generally hard to find. We saw only 15 species. Best Birds were two immature red-tailed hawks that chased each other.
Canada Goose (Branta canadensis) 75 on Flagstaff Hill Mourning Dove (Zenaida macroura) 3 Red-tailed Hawk (Buteo jamaicensis) 2 Immature hawks lazily chasing each other up the creek Red-bellied Woodpecker (Melanerpes carolinus) 3 Downy Woodpecker (Dryobates pubescens) 2 Northern Flicker (Colaptes auratus) 6 Least Flycatcher (Empidonax minimus) 1 Blue Jay (Cyanocitta cristata) 8 Tufted Titmouse (Baeolophus bicolor) 1 European Starling (Sturnus vulgaris) 20 American Robin (Turdus migratorius) 25 House Finch (Haemorhous mexicanus) 16 American Goldfinch (Spinus tristis) 3 Song Sparrow (Melospiza melodia) 4 Adult & fledgling were not the color we expected. Both had a rumpled appearance as if they got dirty somehow. Northern Cardinal (Cardinalis cardinalis) 4
Right now adult spotted lanternflies are flying to find each other and their host plant, Ailanthus, to mate, lay eggs and die. In Pittsburgh we had a major invasion in 2023 from mid August to mid September but they’re not so bad this year, as expected based on their initial North American invasion in Eastern Pennsylvania. There is more to learn from that initial invasion including lists of their top bird and insect predators.
#1 Bird: Chickens! Backyard chickens eat a lot more than grain and are known to gobble up spotted lanternfly nymphs when they find them. The nymph phase ran from June to late July in Pittsburgh this year.
Wild Birds: Plenty of birds have figured out that spotted lanternflies are good to eat including visiting warblers. The top predators, however, are resident birds and one migratory species that leaves for the winter, shown in the slideshow below. All of them catch both nymphs and adults: Northern cardinals, gray catbirds, blue jays and tufted titmice.
We then tested 10 commercially available or easily field-collected generalist predators to determine if these potential biological control agents could reduce L. delicatula populations. Spined soldier bugs (Podisus maculiventris), Carolina mantids (Stagmomantis carolina), and Chinese mantids (Tenodera sinensis) were the most effective at reducing prey populations, indicating they have promise as effective natural control agents.
Spined soldier bugs (Podisus maculiventris) are native insects that resemble brown marmorated stink bugs from Asia, except that these eat insects not plants. They’re called soldiers because they gather in groups to attack and kill their prey. Awesome!
Here’s an adult. Notice the resemblance to the stink bug.
The next most effective insect predator of spotted lanternflies is the Chinese praying mantis (Tenodera sinensis) which naturally recognizes their fellow Asian insect food.
What moth? Frick, 28 August 2025 (photo by Kate St. John)
30 August 2025
This was certainly the week for insects, especially on Thursday when cold temperatures made them sluggish. Here are a few that I’ve seen this week, some of which I cannot identify.
At top, what moth is this at Frick Park on Thursday? Google Lens gives so many answers that I am not sure which one to pick.
Below, not-a-moth this is an end-banded netwing beetle (Calopteron terminale). Most, but not all photos, show a black band in the middle too.
End-banded netwing beetle, Frick, 28 August 2025 (photo by Kate St. John)
An old spider web is draped like a curtain on a twig and stinging nettle in Frick Park.
Spiderweb on stinging nettle, Frick, 28 August 2025 (photo by Kate St. John)
When I got back to my car there was a weevil on the window (yes, my car is dirty). I don’t know what species.
A weevil but which one? Frick, 28 August 2025 (photo by Kate St. John)
Aphids have been sucking the juices out of Schenley Park’s false sunflowers for about a month now. Our abnormally dry weather makes the plants less juicy.
Aphids on false sunflower, Schenley, 29 August 2025 (photo by Kate St. John)
Reminder! I’ll be leading an outing at Schenley Park tomorrow, 31 August, starting from the Schenley Park Visitors Center at 8:30am. More info here.
Can you see the hawk? We’ll look for him tomorrow. He was watching near Panther Hollow Lake yesterday.
