Category Archives: Mammals

Who’s Herding Who?

Border collie herding sheep (photo from Wikimedia Commons)

5 October 2022

Some dogs are bred to herd sheep and the instinct is so deep that they try to herd at every opportunity.

However, training helps. So does experience, as shown in this tweet from @SlenderSherbet.

(photo from Wikimedia Commons, embedded tweet from @SlenderSherbet)

When Will The Chipmunks Disappear?

Eastern chipmunk (photo from Wikimedia Commons)

3 October 2022

The hardest thing to notice in Nature is the date of an absence. When did the last junco leave in the spring? When did the last groundhog go into hibernation?

Right now eastern chipmunks (Tamias striatus) are busy gathering nuts to store in their underground burrows for the winter. As the season changes and temperatures drop they will disappear into their burrows to enter torpor, sleeping off and on through the winter.

The warm winters of climate change can fool them into not entering torpor but the result is deadly. Only 10% survive. Find out why in this vintage blog:

Meanwhile I will hope our chipmunks disappear and will try to figure when they do it.

Here’s how I notice an absence: I write down every day when I do see them and then scan my notes for days when I’ve not logged them anymore.

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

Deer Are Picky Eaters

Arrowwood viburnum, Schenley Park, September 2019 (photo by Kate St. John)

29 September 2022

In western Pennsylvania, where we have a high deer population, gardeners have learned from experience that white-tailed deer will eat some plants and not others. They heavily browse their favorites to the point of killing them but leave others untouched, even plants in the same genus.

Viburnum is a case in point. Gardening advice at Rutgers University’s Landscape Plants Rated by Deer Resistance indicates that arrowwood viburnum (Viburnum dentatum) is deer resistant. Pictured at top, these shrubs are healthy in Schenley Park where the deer population is more than 100 per square mile.

Deer also don’t like the Japanese snowball (Viburnum plicatum) which thrives as an invasive in Frick Park, shown below.

Viburnum plicatum fruit, Schenley, July 2019 (photo by Kate St. John)

But they love our native hobblebush (Viburnum lactoides) and consume it to local extinction.

Hobblebush (Viburnum lactoides) is a favorite food of deer (photo taken in Maine by Kate St. John)

Read about hobblebush in this vintage article.

When it comes to viburnum, deer are picky eaters.

(photos by Kate St. John)

The Most Teeth in North America?

Sperm whale skeleton showing teeth (photo from Wikimedia Commons)

19 September 2022

Adult humans typically have 32 teeth after our wisdom teeth come in at age 12-14, but our count is low compared to other animals.

7-year-old smile with missing tooth (photo from Wikimedia Commons)

Which animal in North America has the most teeth?

The Virginia opossum (Didelphis virginiana) is a contender with 50 teeth in his small mouth. He shows them when he feels threatened.

Opossum showing teeth (photo from Wikimedia Commons)

Some say that sharks have the most teeth but as far as I can tell their tooth count, often lower than 100, is not as remarkable as their tooth replacement. For instance, young lemon sharks replace all their teeth every 7-8 days so that in their lifetimes “the lemon shark Negaprion brevirostris, may produce 20,000 teeth in its first 25 years, and may live as long as 50 years.

The winner of the most-teeth contest are land and sea snails which usually have between 10-15,000 teeth, though some may have up to 25,000. This includes snails in the ocean off the North American coasts.

Studies of the European garden snail (Cornu aspersum), an alien in North America, indicate it has 14,000 teeth. Take a look at his toothy mouth under a microscope and find out why snails have so many teeth at NMH.org: Microscopic look at snail jaws.

European garden snail (photo from Wikimedia Commons)

p.s. Amazingly, the most abundantly land snail found in Pennsylvania, Zonitoides arboreus, has no teeth at all!

Quick gloss snail, Zonitoides arboreus, Edgewater, Maryland (photo from Wikimedia Commons)

(photos from Wikimedia Commons; click on the captions to see the originals)

Why Is Wingstem Thriving in City Parks?

Honeybee approaches wingstem, Frick Park, 8 Sep 2022 (photo by Kate St. John)

17 September 2022

In Schenley and Frick Parks you can look straight through the forest if you duck your head below four feet high. In Schenley Park the ground is often bare and most plants in that four-foot zone are gone. But one flower, wingstem (Verbesina alternifolia), is doing just fine in the city parks.

Wingstem, Frick Park, 8 Sep 2022

The absence of cover from the ground to 4 – 5 feet is called a browseline (below) and is evidence of an overpopulation of white-tailed deer.

Bare ground and absence of cover below the trees in Schenley Park, September 2022 (photo by Kate St. John)

According to this KDKA report, the deer population in Schenley Park is estimated at 80-150, which roughly equates to 100-200 deer per square mile. A healthy population in a balanced forest would be 20-30 deer per square mile, so any plant that survives in the Pittsburgh’s city parks is something that deer don’t eat.

Doe browsing in Schenley Park, September 2022 (photo by Kate Sr. John)

So why don’t deer eat wingstem?

A thicket of wingstem on the “elbow” trail, Frick Park, 8 Sep 2022 (photo by Kate St. John)

The leaves are bitter!

Find out more about wingstem at Illinois wildflowers.

(photos by Kate St. John)

Chipmunks Chip and Tock

Chipmunk with full cheeks (photo by Chuck Tague)

15 September 2022

At this time of year the birds are not singing but you often hear a “chip” note in the woods. It’s not the sound of a bird but instead a chipmunk, making the noise that puts “chip” in his name.

“Chip” is warning sound that means Danger From the Ground. Chip Chip Chip Chip, the speaker is warning of a ground-based predator — a cat, raccoon, snake, etc.

Chipmunks “chip” at different speeds, even during the same chipping session, as seen in the 4.5 minute video below. The tonal quality and variable speed give us a hint that it’s a chipmunk speaking, not a bird.

The second most common chipmunk sound is another warning.

“Tock” means Danger From The Air — a clue that birders should look for a raptor. Tock Tock Tock Tock. Listen and learn in this vintage article.

p.s. This article explains the chipmunk’s vocalizations: What Sounds Does A Chipmunk Make?

(photo by Chuck Tague)

Opposable Thumbs

Childrens’ game with hands (photo from Wikimedia Commons)

7 September 2022

We humans are gifted with opposable thumbs inherited from ancestors who lived in the trees. We can firmly grasp and manipulate objects of many different shapes and our hands are very precise at gripping.

A thumb is called “opposable” when the joint allows a rotary movement that swings the thumb on its own axis to face and touch the fingertips. In North America there is only one other mammal with this feature and the thumbs are on its back feet, not the front.

In the photo below the Virginia opossum’s (Didelphis virginiana) opposable back thumb grasps the branch: four toes on one side of the branch, one toe on the other.

Virginia opossum grasping a small branch with its hind foot (photo from Wikimedia Commons)

You can see it in this skeleton …

Virginia opossum skeleton. Notice the feet (photo from Wikimedia Commons)

… and on the possum’s hind foot with its relatively large thumb pad.

Virginia opossum hind foot (photo from Wikimedia Commons)

The straight-toed front feet and opposable-thumb back feet make the opossum’s tracks look like paint splats.

Tracks of Virginia opossum (photo from Wikimedia Commons)

And before we adjourn, let’s lay a misconception to rest.

Squirrels and raccoons do not have opposable thumbs.

I was surprised by this for raccoons (Procyon lotor) because their paws are so dexterous. However none of the raccoons’ paws has a toe with a separate hinge. Their paws are flat.

Raccoon and the raccoon’s front paw (photos from Wikimedia Commons)

You can see this in their footprints.

Raccoon track and dog print at Schenley Park (photo by Kate St. John)

So.

We have something vaguely in common with Virginia opposums.

(photos from Wikimedia Commons and by Kate St. John; click on the captions to see the originals)

Meet the Familiar: Synanthrope

Pigeons on a traffic light (photo from Wikimedia Commons)

28 August 2022

I had never seen the word “synanthrope” until I found it attached to this photo.

Passer domesticus as synanthrope (photo from Wikimedia Commons)

House sparrows are synanthropes. So are pigeons.

synanthrope (syn-anthrope) [from Greek: syn-anthrope: syn=”together with” + anthropos=”man”] is a wild animal or plant that lives near, and benefits from, an association with humans and the somewhat artificial habitats that people create around themselves.

Wikipedia: Synanthrope

We can be forgiven for not knowing this little-used word since its present meaning is only 74 years old(*).

Synanthropes live with us but we often disparage them. They are wild but too familiar, too “tame,” too weedy. Here are some more examples.

Dandelions (Taraxacum sp.)

Dandelions in the grass (photo by Kate St. John)

Horseweed (Erigeron canadensis) and pilewort (Erechtites hieraciifolius) are native North American plants that like disturbed soil. We notice them in August when they start to look ugly.

Horseweed (photo from Wikimedia Commons)
Closeup of pilewort flowers (photo by Kate St. John)

Two local mammals may be recent synanthropes, formerly shunning humans but now benefiting from our habitat.

Squirrels love our birdseed and shelter (attics).

Squirrel on the bird feeder (photo from Wikimedia Commons)

White-tailed deer (Odocoileus virginianus) prefer forest edges next to open areas, a landscape often created by humans. Have deer become synanthropes?

Buck in velvet at Allegheny Cemetery, Pittsburgh (photo from Wikimedia Commons)

p.s. (*) Merriam-Webster explains that the word was introduced by botanist Theodor von Heldreich at a botanical conference in Paris, 16-24 August 1878, making its first-ever use almost exactly 144 years ago.

(photos from Wikimedia Commons and Kate St. John)

Eradicated By Deer

Doe in Schenley Park, July 2019 (photo by Kate St. John)

22 August 2022

Back in 2010 the City of Pittsburgh commissioned a deer count in the parks that found the population was too high and not sustainable for the habitat. Nothing has been done since then to reduce the deer population other then accidentally killing them with our cars.

Twelve years have passed. According to deer experts “Urban deer can live for 10 years; the deer population, if unchecked, doubles about every two years.” Schenley Park now has as much as 64 times the number of deer we had in 2010. This is truly unsustainable, even for the deer themselves.

8-point buck in Schenley Park, 21 August 2022 (photo by Kate St. John)

Schenley’s deer have completely consumed all the good food plants and are starting to nibble the poisonous ones. The browse line is painfully obvious. In the process deer have eradicated their favorite plants from Schenley Park.

Orange (Impatiens capensis) & Yellow jewelweed (Impatiens pallida)

Orange jewelweed and yellow jewelweed provide nectar for hummingbirds and bumblebees and are a favored food of deer.

Orange jewelweed in Schenley Park in 2018 (photo by Kate St. John)
Yellow jewelweed in Schenley Park in 2018 (photo by Kate St. John)

Both jewelweeds were prolific in Schenley Park as recently as four years ago.

Orange jewelweed was prolific in 2017 (photo by Kate St. John)

But this year all the accessible plants have been eaten down to bare stems. The only ones that flower are those in spots unreachable by deer — on extremely steep slopes or hidden among thick cattails in Panther Hollow Lake.

Deer ate the jewelweed, no flowers, no leaves (photo by Kate St. John)

Jewelweeds are annuals that must re-seed every year but no seeds are produced in this deer-browsed landscape. Impatiens will disappear from Schenley Park when the seed bank is exhausted.

False Solomon’s Seal (Maianthemum racemosum)

False Solomon’s seal used to grow throughout Schenley Park and it carpeted the ground in an area near the Bridle Trail. All of it has been eaten to the ground since 2014. Here’s what it looked like eight years ago.

False Solomon’s seal blooming in May 2012 (photo by Kate St. John)
False Solomon’s seal in August 2014 (photo by Kate St. John)
White wood asters (Eurybia divaricata)

White wood asters used to bloom in Schenley’s woods. Not anymore. Here’s what they looked like in 2013.

White wood asters in Schenley Park, August 2013 (photo by Kate St. John)

Eradicated plants are indirect evidence of too many deer in Schenley Park. Direct evidence is their visibility every day.

A sustainably-sized deer herd would hide in the underbrush while sleeping during the day, but the browse line in Schenley is so severe there is no cover for them. The large herd has coped by becoming accustomed to people and leashed dogs.

I stood near this group of three deer on Sunday 21 August using my snapshot camera zoomed to 90mm (approximately 2x). This 8-point buck did not care that I was there.

8-point buck in velvet, Schenley Park, 21 August 2022 (photo by Kate St. John)
Young doe and buck browsing in Schenley Park, 21 August 2022 (photo by Kate St. John)
Doe watches a husky dog on a leash approach in the distance, Schenley Park, 21 August 2022 (photo by Kate St. John)

(photos by Kate St. John)

UPDATE: I was interviewed by Andy Sheehan, KDKA News, 25 August 2022. Click on this link or on the image below. Experts warn deer are destroying Pittsburgh’s parks and moving into neighborhoods.

Video: Experts warn deer are destroying Pittsburgh’s parks and moving into neighborhoods

Three articles, 2017-2019, about deer in Allegheny County by John Hayes, Post-Gazette:

I Love Yew

White-tailed deer browsing leaves in Newark, OH (photo from Wikimedia Commons)

17 August 2022

Yews are popular landscaping shrubs but they don’t last long in the face of deer overpopulation.

All yew species are toxic to some degree, but our native Taxus canadensis is less toxic than others and was used medicinally. Deer don’t read the warning labels. They love yew.

Closeup of Canadian yew branch and leaves (photo from Wikimedia Commons)
Canadian yew aril and branch (photo from Wikimedia Commons)

Every night they creep up behind Carnegie Museum and browse the yews along the driveway to the parking garage. They nip off the small branches and eat all the leaves. The shrubs struggle to grow new leaves for photosynthesis before the deer return.

Yew overbrowsed by deer behind Carnegie Museum, 16 August 2022 (photo by Kate St. John)

Deer have killed the yews closest to the sidewalk (dead twigs), overbrowsed the middle shrubs (green knobs), and cannot yet reach the tallest branches. But they are eating their way there.

Yews browsed by deer behind Carnegie Museum, 16 Aug 2022 (photo by Kate St. John)

Don’t assume their love stops with yew. There are more delectables in Schenley Park that they adore. Soon we’ll explore more.

Doe and fawn browsing a tree (photo from Wikimedia Commons)

p.s. Just for yuks here are 13 garden plants that deer will utterly destroy. Meanwhile, did you know that Japanese yew (Taxus cuspidata) is so toxic it can kill wildlife? Unfortunately its pollen triggers asthma.

Japanese yew (Taxus cuspidata) closeup of leaves and stem (photo from Wikimedia Commons)

(photos from Wikimedia Commons; click on the captions to see the originals)