All posts by Kate St. John

Cinnamon Repels Ants

Cinnamon sticks, powder and flowers (photo of Ceylon cinnamon from Wikimedia Commons)

Perhaps you already know this but it was news to me: Cinnamon repels ants.

Cinnamon comes from the dried inner bark of a tropical evergreen, the cinnamon tree (Cinnamomum sp.). Ants would eat these trees alive if they could but the cinnamon genus evolved a very effective defense: two chemicals, Cinnamaldehyde and Cinnamyl alcohol, that are toxic to ants. Ants stay away from cinnamon.

In this 9-minute video, the guy from You Can Science It shows that even swarming, warring ants will drop what they’re doing when confronted with cinnamon. He theorizes that it changes their messaging from “Kill the other colony” to “Oh no! It’s cinnamon!” (video begins where he starts discussing cinnamon. Click here for the full video.)

Yes, cinnamon repels ants but it has to be fresh and you have to use a lot of it.

Read more about this experiment and the research behind it in this 2015 blog post at You Can Science It.

(photo and illustration from Wikimedia Commons, video from You Can Science It on YouTube)

Spiny Tongues and Glowing Beaks

Puffin with a beakful of fish (photo by Steve Garvie, Creative Commons license on Flickr)

There are many cool things about Atlantic puffins (Fratercula arctica). Here are two things that might come as a surprise.

(1) When Atlantic puffins fly back to their nests to feed their hungry chicks they need to carry as many fish as possible. How do they clamp them in their beaks? They press their spiny tongues on the fish to hold them against the roof of the mouth.

(B) We think puffins’ beaks are beautiful but we’re seeing only half of it. Where we see yellowish stripes the puffins see glowing ultraviolet. Read more about their colorful beaks in this article from Audubon.org.

Atlantic Puffins engaged in (a) billing behaviour, which is associated with sexual signalling (Photo: T. Finch). We identified photoluminescence on the cere (arrow) and lamellae of Puffins found deceased in (b) UK and (c) Canada.

Atlantic Puffins engaged in (a) billing behavior; (b, c) photoluminescence of the bills in UV light (Photo: T. Finch from “Photoluminescence in the bill of the Atlantic Puffin Fratercula arctica,” scientific figure via ResearchGate).

(photo with fish by Steve Garvie, Creative Commons license on Flickr; puffins ‘billing’ in courtship and UV glowing beaks from Photoluminescence in the bill of the Atlantic Puffin Fratercula arctica via Researchgate)

Water Instead Of Lava

Halema’uma’u Crater at Kilauea Volcano, Hawaii, 13 July 2018 (photo from Wikimedia Commons)

Late last month observers discovered a small green pond at the bottom of Halema’uma’u Crater at Kilauea volcano. Water inside the crater is rather amazing since Kilauea is the active volcano on the Big Island of Hawai’i that erupted violently in 2018, destroying parts of Leilani Estates, Highway 132, Vacationland and Kapoho.

Geologists wondered if the green spot was a rock or algae so they flew over the crater several times looking for a telltale reflection to indicate it was water. Yes, it’s wet.

A week’s worth of photos also showed that pond had grown since it’s original “size of a pickup truck.”

Halema’uma’u, as taken by the USGS Hawaiian Volcano Observatory on August 1, 2019. Inset shows water pond. USGS photos taken by S. Conway.

Geologists don’t know how the pond got there but it’s worth watching to find out more. Fortunately by August 2 they’d found a safe place to view it from the crater’s edge.

Read more about the pond here or follow the news on Volcano Watch at USGS.

(photo credits: crater view from Wikimedia Commons, Halema’uma’u pond from USGS; click on the captions to see the originals)

Very Tame

White-tailed deer are numerous and very tame in Schenley Park. Last week I encountered a doe with twin fawns near the swimming pool.

The family became alert while I was staring at them, but the mother has learned that we humans aren’t dangerous and is teaching it to her kids. How many generations does it take for the herd to become this tame?

Doe in Schenley Park, 29 July 2019 (photo by Kate St. John)
Her twin fawns, 29 July 2019 (photo by Kate St. John)

In the past ten years I’ve seen the landscape change in Schenley Park while the deer population has grown exponentially. Where there used to be thick slopes of false Solomon’s seal and yellow jewelweed there is nothing green now, just carpets of fallen leaves. Having eaten the good stuff they are working on less tasty food, avoiding the poisonous plants such as white snakeroot at their feet in these photos. Some day their range will fail them.

I now suspect that just as a deer herd lives in mortal fear of its wolves, so does a mountain live in mortal fear of its deer. And perhaps with better cause, for while a buck pulled down by wolves can be replaced in two or three years, a range pulled down by too many deer may fail of replacement in as many decades.

Aldo Leopold, “Thinking Like A Mountain,” A Sand County Almanac

p.s. Click here for a photo of an 8-point buck I saw in the park yesterday, August 3.

p.p.s. Also see this article: Too Many Deer: A Bigger Threat to Eastern Forests than Climate Change?

(photos by Kate St. John, Schenley Park, 29 July 2019)

Blonde Groundhog

Blonde-colored groundhog near The Waterfront (photo by Bob Holder)

If you bike the Great Allegheny Passage at the eastern end of The Waterfront near Bristol Metals you may see this blonde-colored groundhog. His color has earned him the nickname “Lou.”

Lou isn’t the normal color for a groundhog. They’re usually brown like this one.

Groundhog in a tree at Flag Plaza, 31 May 2014 (photo by Kate St.John)
Groundhog in a tree at Flag Plaza, 31 May 2014 (photo by Kate St.John)

Lou is leucistic, a condition that has a partial loss of pigment in his skin or fur but not in his eyes. Pigment loss in the eyes — making them red (or green or blue) — indicates albinism.

Thanks to Yale Cohen for mentioning Lou and to Bob Holder for the photo.

(photo by Bob Holder)

Ancient Great Lakes

Beach at Presque Isle State Park, Lake Erie (photo from Wikimedia Commons)

If you’re planning a Great Lakes beach vacation, here’s something to ponder. Your favorite beach wasn’t there 14,000 years ago.

The Great Lakes formed as ice melted at the end of the last glacial period. They’re now the largest group of freshwater lakes on Earth and contain 21% of the world’s surface fresh water.

The Great Lakes (labeled) as seen from satellite (image from Wikimedia Commons)

But 14,000 years ago most of them were under ice and the lakes that existed weren’t in the same place. The western part of Lake Erie was under Lake Maumee. The toe of Lake Michigan was covered by Lake Chicago. As the ice receded the Great lakes took on their present shape.

A lot has changed in the last 14,000 years. Browse the maps below to find your beach at the ancient Great Lakes.

(photo and maps from Wikimedia Commons; click on the captions to see the originals)

Lightning Indoors

Lightning strike (photo from Wikimedia Commons)

We all know it’s unsafe outdoors in a thunderstorm but did you know that lightning can be dangerous indoors, too? It depends on what you’re doing.

When lightning strikes a building it follows the quickest path to the ground. If the building has ample lightning rods it follows their lead. Otherwise it travels through the plumbing, wiring, metal door jambs, even the metal rebar inside concrete. If a building doesn’t have plumbing or electricity it’s not safe during lightning.

Here are some indoor lightning safety tips, paraphrased from weather.gov.

  • Don’t touch any electrical equipment unless it’s completely cordless. Anything that’s plugged in is bad.
    • A cellphone or cordless phone is OK, but not a landline that’s got a cord.
    • A laptop is OK if it’s not plugged into any wires, not even the charger.
    • Don’t run around unplugging everything while the storm’s in progress. Lightning could strike while your hand is on the cord.
  • Avoid the plumbing. Lightning can travel in water. Don’t take a shower, wash your hands, etc.
  • Stay away from the windows, not because lightning will come through the window (it won’t), but because it will explode the glass if it hits, creating lots of flying glass.
  • This one is the hardest: Avoid metal structural components including metal window frames, door jambs, and concrete rebar. If you’re in a concrete building good luck!

Of course it goes without saying that carports, porches and balconies are not safe because they’re outdoors. Cars are safe, but only if the windows are closed.

Read some hair raising lightning stories (pun intended) in this vintage article: Looking Forward to a Little Less Lightning.

p.s. Check out the Real Time Lightning Map to see where lightning is striking right now!

(photo from Wikimedia Commons; click on the caption to see the original)

Why So Many Landslides?

After a rainy period or spring thaw in Pittsburgh we inevitably see devastating landslides on the news. Why does Pittsburgh have so many landslides and why are they associated with rain or moisture?

The problem is a combination of a particular bedrock with our steep hillsides. Where both are present the location is landslide prone, as shown on the City of Pittsburgh map below. (Click here to see the City’s interactive landslide-prone map and zoom in for details. Click here for the Allegheny County interactive landslide map.)

Landslide prone areas (screenshot from Pittsburgh GIS Data Download Page)

The house in the video above was inside a landslide zone on Semicir Street overlooking Riverview Park. Add water and … the house collapsed!

The bedrock at fault is Pittsburgh redbed, a claystone that disintegrates into smaller and smaller pieces if exposed to pressure when it’s wet. Redbed is usually under pressure because it’s underneath solid rock and overlying soil. Add water to a steep slope and you have a landslide.

This sandstone boulder on the Bridle Trail in Schenley Park was part of the escarpment above it until the redbed layer beneath it gave way.

An old landslide in Schenley Park on the Bridle Trail, July 2019 (photo by Kate St. John)

Here’s a future landslide on the Lower Panther Hollow Trail. This sandstone boulder, high above my head, will fall some day because the slow drip of water over the boulder has disintegrated the underlying redbed. Notice the reddish crumbled stones.

Sandstone boulder is undercut, a landslide waiting to happen at Lower Panther Hollow Trail, Schenley Park, July 2019 (photo by Kate St. John)

I had read that Pittsburgh redbed disintegrates when wet but I wanted to see for myself so I gathered some redbed rocks and ran an experiment.

Thousands of years ago these small crumbles were a much bigger solid rock but water had already acted on them. Will the crumbles disintegrate in the presence of water and pressure? I kept some rocks dry and soaked others for a day. Here’s my experiment.

Add water and pressure to Pittsburgh redbed claystone and … Watch out below!

p.s. For a really spectacular landslide, check out what happened to Route 30 in East Pittsburgh in April 2018.

(photos and redbed experiment by Kate St. John, house collapse video embedded from WTAE Pittsburgh on YouTube, map from Pittsburgh GIS Data)

Reflect Light, Stay Cool

Nankeen kestrel in Australia (photo from Wikimedia Commons)

How do birds stay cool in hot climates, especially when there’s no shade?

A 2018 Australian study in the journal Nature found that some birds can reflect the hottest part of sunlight, the near infrared (NIR) spectrum.

Near infrared is long-wavelength light beyond the red end of the visible spectrum. Though we can’t see this wavelength we can feel its heat. In fact more than half the sunlight that reaches Earth is in the infrared spectrum, as shown in the graph below.

Most of the sunlight that reaches the Earth’s surface is in the infrared range (simplified image from Wikimedia Commons)

Australia is a good place to study cooling techniques in birds because 70% of the continent is hot, dry and very sunny. The Australian study examined museum specimens of 90 species, classifying them by habitat and testing them for their NIR reflectant properties. Two species stood out.

The nankeen kestrel (Falco cenchroides), named for his yellow color (above), reflects near infrared light from the crown of his head. The azure kingfisher (Ceyx azurea) stays cool by reflecting NIR from his chest. Their feathers can reflect NIR because they have rounder barbs and denser barbules.

Azure kingfisher, Queensland, Australia (featured picture on Wikimedia Commons)

Here’s a graph from the study that compares them with two other species.

Graph of four species (image from Reflectivity article in Nature Communications)

The nankeen kestrel and azure kingfisher are at the top of the NIR reflective scale but low reflectors of visible and UV light. The reverse is true of the blueish bird, a male superb fairywren (Malurus cyaneus). He’s great at reflecting UV and visible light, probably because he lives where it’s moist and shady. The great cormorant (Phalacrocorax carbo) doesn’t reflect much light at all.

Interestingly, near infrared reflectivity is more prevalent in small birds because they benefit more for their size. You can’t tell it from the photo but the azure kingfisher is only as big as a sparrow.

Too hot? Reflect near infrared light to stay cool.

(image credits: nankeen kestrel, sunlight graph and azure kingfisher from Wikimedia Commons. Graph from “Reflection of near-infrared light confers thermal protection in birds” at Nature.com, Creative Commons license. Click on the captions to see the originals)

Deer Damage in The City

Arborvitae showing deer damage, Greenfield neighborhood, Pittsburgh PA, 17 July 2019 (photo by Kate St. John)

Yesterday in Schenley Park when we saw several white-tailed deer quite close to us, I remarked that the deer population is too high for the park.

How can you tell if your neighborhood has too many deer? Take a look at the arborvitae.

Many species of arborvitae (Thuja spp.) are planted as privacy hedges including our native Thuja occidentalis or northern whitecedar.

In the wild and in our yards Thuja trees are a favorite food of white-tailed deer. They browse it from the ground up to the height of their outstretched necks.

When the number of deer is in balance with the landscape, arborvitae have a normal tapered shape. You’d never notice that the deer are eating them.

Normal tapered shape of arborvitae tree (photo from Wikimedia Commons)

When there are more deer than the landscape can handle, their browsing is intense. The trees are cropped close to the trunk — even down to the bark — because the plants can’t replace their branches fast enough.

If your arborvitae trees look like the row shown at top, there are too many deer in your neighborhood, the landscape is out of balance. “Too many” can happen fast. Deer can double their population in just two to three years.

I photographed that row of damaged trees just six blocks from my house. Yes, my city neighborhood has too many deer now. We could protect our trees with netting as described in this video. Or we could give up and never plant arborvitae again.

p.s. There are too many deer everywhere in the eastern U.S., even in the forest. Read more here.

(photo by Kate St. John)