All posts by Kate St. John

Another Reason to Avoid Ticks: Powassan

Insects, Musings & News
Black-legged tick (photo from Wikimedia Commons)

14 August 2024

If you aren’t already avoiding black-legged ticks (Ixodes scapularis) because of Lyme disease, yesterday’s announcement is another reason to be very careful.

The Allegheny County Health Department has announced that the first human case of Powassan virus disease has been detected in the area. It’s the first time the tick-borne virus has been seen in the county, and the first case in the state this year.

— Post Gazette: First human case of rare but deadly tick virus detected in Allegheny County

Powassan is a rare, but growing, disease that can only be caught from a black-legged tick bite. Initial symptoms can include fever, headache, vomiting, and weakness but it can also cause severe illness including inflammation of the brain (encephalitis) or the membranes around the brain and spinal cord (meningitis). This can result in long term neurological effects.

There is no treatment for Powassan and no vaccine. All that can be done is to wait for it to run its course and mitigate the symptoms.

embedded video from WTAE-TV Pittsburgh on YouTube

It is no surprise that this happened at this time of year. Summer is when black-legged ticks are tiny nymphs.

Black-legged tick life cycle (diagram from CDC enhanced with lifeform names)

Here’s how big they are compared to an adult. No wonder we don’t notice them sucking our blood!

Black-legged ticks, adult and nymph, on hand (photo from Wikimedia Commons)

There are two ways to prevent Lyme disease.

#1. Check your body for ticks after you’ve been outdoors. There may be ticks in your own backyard so check every time.

How to do a tick check (image from PA Dept of Health & CDC.gov)

#2 Keep ticks off your clothes and skin. Wear long pants and long sleeves and spray your clothes with permethrin. Some suggest using DEET on your skin (if you wear shorts) but I can attest that long pants sprayed with permethrin is much better.

It’s Spray Your Clothes Day (photo by Kate St. John)

Stay safe outdoors. Avoid ticks

It’s time for Spray Your Clothes Day

For more information, see the Post-Gazette: First human case of rare but deadly tick virus detected in Allegheny County.

To See or Not To See Ultraviolet Light

Bird Anatomy, Birds of Prey, Songbirds
Female European starling, Golden eagle (photos from Wikimedia Commons)

13 August 2024

Just because an animal has UV receptors in its eyes does not mean it can see ultraviolet light. A recent BBC video, below, reveals some surprising things about the use and perception of ultraviolet light in starlings (Sturnus vulgaris) and raptors, especially golden eagles (Aquila chrysaetos). For instance:

  • Starlings and golden eagles both have UV receptors in their eyes.
  • Female starlings have feathers that reflect UV. The more UV a female reflects the more successful she is at breeding. Male starlings like the glow we humans cannot see.
  • UV light scatters more. If you can see UV light, it makes images blurry.
  • Raptors have UV receptors in their eyes but they cannot see it because their lenses filter it out. The golden eagle’s vision is sharper because he cannot see UV.
  • Scientists used to think kestrels hunted by seeing the UV reflective paths of rodent urine. Nope. Kestrel eyes filter out UV so that theory has been disproved.

Interesting conclusions:

  • Because I thought that raptors could see UV, I used to wonder how flashy UV-reflective songbirds managed to evade predators. Answer, the predators cannot see that flashy stuff!
  • UV light damages the eye so there is an advantage to not seeing it for most of one’s life.
  • Human eyes have UV receptors but we cannot see it because our lens filters out UV. There are exceptions based on age and lack of lenses.
    • Exception#1: Young people up to age 30 can see near UV, the wavelengths closest to our visible color range, per a 2018 Univ of Georgia study.
    • Exception#2: Those without lenses in their eyes can see near UV. This includes those born without lenses and those who had cataract surgery in the early days. Claude Monet had cataract surgery in 1923 with no lens replacement and could see near UV.

Read more about human perception of UV light in this Live Science article: Can Humans See Ultraviolet Light?

Swarms of Swallows

Bird Behavior, Migration, Songbirds
Tree swallow (photo from Wikimedia Commons)

12 August 2024

On Friday I wrote about a swarm of dragonflies. Today it’s a swarm of swallows.

On 31 July my sister watched more than two dozen tree swallows swarm over her yard in Tidewater Virginia. They were feasting on flying bugs for about 20 minutes, and then they were gone.

After they finish breeding, tree swallows (Tachycineta bicolor) gather in ever-growing flocks in July and August and begin their southward migration. In transit they seek out swarms of insects that may include true flies (Diptera), dragonflies and damselflies (Odonata).

Peak tree swallow migration occurs in early to mid-fall. I was at Cape Cod on 1 October 2017 when I witnessed a huge flock at West Dennis Beach. Abundant bugs attracted the tree swallows; abundant swallows attracted a falcon who captured one in his talons (top right of photo below).

Thousands of tree swallows and one falcon with prey, West Dennis Beach, MA, 1 Oct 2017 (photo by Kate St.John)
Thousands of tree swallows and one falcon with prey, West Dennis Beach, MA, 1 Oct 2017 (photo by Kate St.John)

On 6 October 2021, Mike of Mike’s Nature Connection witnessed a similar flock on Cape Cod.

video embedded from Mike’s Nature Connection on YouTube

If you live in the Mississippi or Atlantic flyways, or at their wintering grounds in Florida or Louisiana, there’s still time to see swarms of tree swallows. Watch their annual movements in this weekly abundance animation from eBird.

Tree Swallow Weekly Abundance throughout its range (animation from eBird)

See this map for yourself at eBird Status and Trends > Tree Swallow > Weekly Abundance.

Strandbeests Walk the Beach Where Art and Science Meet

Musings & News
Strandbeest in the Netherlands, Sept 2016 (photo from Wikimedia Commons)

11 August 2024

It looks like a skeletal sailing ship and in a way it is. Except that it walks. Like a giant bug.

Strandbeests are created by Dutch physicist turned artist, Theo Jansen, who has worked on them since 1990. He named them strandbeest which literally means “beach animal” in Dutch. They are native to the Netherlands.

Strandbeests are powered only by wind. Some newer “species” can use the wind to store compressed air in onboard PET bottles — a wind stomach for the animal — which is later used for power.

video embedded from theo jansen on YouTube

Every year Jansen experiments in summer and designs new ones in winter in a constantly evolving process. Though the beests have existed for more than 30 years they became known only after he posted videos on YouTube about a decade ago. Since then the beests have been on tour. They came to the U.S. in 2014-2016.

And yet they remain mostly unknown, especially to people like me who live far from the beach. I learned about them last week in this 11-minute video that tells their story.

video embedded from Master of Art on YouTube

Visit Theo Jansen’s Strandbeest website for more information. His Frequently Asked Questions are especially useful.

p.s. In case you’re curious, two animations show how the legs move.

Movement of a single leg. Notice that one bar is fixed and the smallest bar rotates.

Movement of a single leg (gif from Wikimedia Commons)

Movement of 6 legs:

Movement of a six legs (gif from Wikimedia Commons)

The green circle shows the rotating axle that powers the legs.

Strandbeest Full Walking Animation from Wikimedia Commons

Seen This Week: August Flowers

Deer, Phenology, Plants & Fungi
Cosmos in bloom, Shadyside, 5 Aug 2024 (photo by Kate St. John)

10 August 2024

This week a flower garden caught my attention with bright yellow-orange cosmos flowers. The plants were in three stages: flowering, going to seed, and seeds formed.

Cosmos suphureus petals are quite showy to attract pollinators to the central disk. When the small flowers inside the disk are fertilized the petals fall off and the disk begins to develop into long thin seedpods.

Cosmos: A single flower going to seed, 5 Aug 2024 (photo by Kate St. John)

When complete the seed pods resemble the hitchhiking seeds of beggar ticks (Bidens frondosa). Both are in the Coreopsideae tribe along with coreoposis, dahlias and many others.

Cosmos: Seeds maturing, 5 Aug 2024 (photo by Kate St. John)

Also seen …

It’s August and, as expected, deer are more visible in Schenley Park. Two does and two fawns approached Panther Hollow Lake on Friday. We can expect to see lots of deer lounging in the city parks in the days ahead. It is The Calm Before The Rut.

Four deer in Schenley Park, 9 Aug 2024 (photo by Kate St. John)

On the cloudy morning of 6 August, daisy fleabane (Erigeron annuus) was still opening its flowers in Frick Park. Fleabane petals respond to light levels. It’s part of Fleabane’s daily exercise program.

Daisy fleabane, still opening flowers, Frick Park, 6 Aug 2024 (photo by Kate St. John)

After all these years I’ve just discovered that horseweed (Erigeron canadensis) is a fleabane. (That’s what comes of learning plants on the fly.)

Horseweed in bloom, near Aspinwall Riverfront Park, 8 Aug 2024 (photo by Kate St. John)

Swarm of Dragonflies on the Move

Insects
Blue dasher male (photo from Wikimedia Commons)

9 August 2024

Two weeks ago you may have seen videos on the Internet of a giant swarm of dragonflies at a Rhode Island beach on 27 July. The swarms at Westerly and South Kingstown were thankfully brief.

Entomologists identified the bugs as blue dashers (Pachydiplax longipennis) which spend their lives at quiet freshwater ponds and marshes but will swarm to seek out new ponds when their population is high. The 27 July bugs were on the move to somewhere else.

Blue dashers are common in the U.S. and are expanding into southern Canada. The males are gorgeous blue with green eyes, while the females and young males are black and yellow.

Male blue dasher (photo from Wikimedia Commons)
Blue dasher female (photo from Wikimedia Commons)

NBC 10 WJAR explains why the bugs visited the beach with on-the-spot videos from the day of the swarm.

video embedded from NBC 10 WJAR on YouTube

Learn Why were there swarms of dragonflies in Rhode Island? at WPRI.com.

How Can You Tell a Moth from a Butterfly?

Insects
Banded or sycamore tussock moth, Halysidota sp. (photo from Wikimedia Commons)

8 August 2024

Bug Season continues this month as caterpillars pupate into adult moths and butterflies. What species have we found? The first step is to decide: Is it a moth or a butterfly? Clues include:

  • Antennae: Feathers vs Knobs
  • Flying: Night vs Day
  • Wing Position At Rest.

To make matters more complicated, skippers are considered butterflies but they break the butterfly Wings At Rest rule.

Zabulon skipper on my thumb, 12 August 2021 (photo by Kate St. John)

For simple pointers to use in the field, check out this vintage article:.

How Do You Know It’s A Moth?

(*) Details about the top photo: According to Wikimedia, the tussock moths Halysidota tessellaris (banded tussock moth) and Halysidota harrisii (sycamore tussock moth) cannot be told apart in the east by a photo.

Spotted Lanternfly Update, early August 2024

Insects, Spotted Lanternflies
Spotted lanternflies along the Three Rivers Heritage Trail, Herr’s Island backchannel, 3 Aug 2024 (photo by Kate St. John)

7 August 2024

Spotted lanternflies (SLF, Lycorma delicatula) were a plague in Pittsburgh last year. This month their adult population is ramping up again. What’s their status now and how do their numbers compare to last summer?

I didn’t pay attention to the first adult spotted lanternfly in 2023 but this year I was ready. My first 2024 sighting was on 18 July. Interestingly I haven’t seen a whole lot of red nymphs and adults compared to last year so I went to a place that was swamped with them in 2023.

On Saturday I visited the Three Rivers Heritage Trail at Herrs Island back channel, a place that was overrun by red nymphs in late July 2023 and had so many winged adults in August and September last year that it was impossible for cyclists and pedestrians to avoid them. The bugs flew into us. It was creepy.

This year on 3 August I found adult lanternflies at the same place but not in an overwhelming number. I counted 16 red nymphs and 68 adults at the most densely populated location. The fact that they were countable is a sign there weren’t that many … yet.

This one tried to avoid being counted. Hah!

Adult spotted lanternfly tries to hide from me at Herrs Island backchannel, 3 August 2024 (photo by Kate St. John)

What I couldn’t count were the bugs above my head sucking sap from invasive vines and ailanthus trees. Their “honeydew” coated the leaves below and “rained” on me at one point. Yuk.

Spotted lanternfly “honeydew” on Virginia creeper leaves below ailanthus trees, 3 August 2024 (photo by Kate St. John)

Last year the worst of the invasion ran from late August to mid September so we still have more to come. Will it be as bad as last year? CBS Pittsburgh provides some expert opinions.

video embedded from CBS Pittsburgh on YouTube

As usual we’ll just have to wait and see.

Tiny Bat Shows Up in Pittsburgh

Mammals
Tricolored bat roosting in Missouri (photo by USFWS from Wikimedia Commons)

6 August 2024

There’s a tiny bat in the eastern U.S. that’s even smaller than the little brown bat. The tricolored bat (Perimyotis subflavus), formerly called the eastern pipistrelle, weighs only 0.16 to 0.23 ounces making it 30% smaller. Tricolored bats, like so many U.S. bats, are declining rapidly due to the fungal disease white nose syndrome and are Endangered in Pennsylvania. It’s pretty amazing that two of these tiny bats showed up in Downtown Pittsburgh in the past two years. We know this because both were rescued and rehabilitated at Humane Animal Rescue of Pittsburgh’s Wildlife Center in Verona (HARP).

To give you an idea of the tricolored’s size, here’s one roosting in a bat cave in North Carolina.

USFWS Biologist Pete Pattavina looks at a roosting tri-colored bat in a North Carolina cave (photo from US Fish and Wildlife)

Before the two bats were found in Pittsburgh, there was no known record of their occurrence here. A female and a male came separately to HARP many months apart so there are probably more of them but who knows where?

Almost a year ago the male arrived at the Wildlife Center.

On August 22nd [2023] we received a male Tricolored Bat…a bat we never would have thought to ever come through our door!  Tricolored Bats are an Endangered Species here in PA. Aside from being moderately emaciated and dehydrated, he sustained no other serious injuries. Weight gain was our main goal, he was 5.2grams at intake and the goal was to get him to at least 7.0grams before release.

— Humane Animal Rescue of Pittsburgh Wildlife Center: 2023 Summer Releases

He was fed the tiniest mealworms, gained weight, and was soon ready for release. HARP points out that bats cannot take off from the ground. “In order for a bat to fly, first it must climb to a high place and then it launches itself by intentionally falling into the air!” Here he walks out of the sheltering blanket, up the tree, and he’s off!

embedded video of Tricolored bat release in late 2023 by Humane Animal Rescue of Pittsburgh Wildlife Center

Sometimes we only discover that a species is near us when it needs our help.

Learn more about the HARP Wildlife Center in Verona on their website and Facebook page. Read about their late summer wildlife releases in 2023 here.

(*) p.s. The bat is called tricolored because each hair on its back has three color bands, like a tabby cat hair. The bat is not striped. All the tips are reddish brown.

Once Again Leaves Turned White

Plants & Fungi
Leaves turned white, Three Rivers Heritage Trail near Herrs Island, 3 Aug 2024 (photo by Kate St. John)

5 August 2024

Last weekend I noticed something I hadn’t seen for a while. Among a sea of green leaves a single plant had turned white. One was at the Herrs Island back channel, the other at Duck Hollow.

My two specimens are not the same species and they haven’t turned white in the same way. The plant above seems to have whitened from its tips inward. The plant below is turning white from the stem outward.

Leaves turning white, Duck Hollow, 2 Aug 2024 (photo by Kate St. John)

The difference in their response may indicate different reasons why they are experiencing chlorosis, or it might be specific to species.

Seven years ago I ran into a similar puzzle and described possible causes in this vintage article.

Leaves Turned White

Have you seen the same thing? Do you know why these leaves turned white? I still don’t know.