Category Archives: Mammals

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)

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)

The Measure Of A Mouse

What size of a hole can a mouse get through? If you have ingenuity, time, and tools you can find out.

Matthias Wandel of woodgears.ca takes an engineering approach to woodworking. When a mouse got into his woodshed he made a wooden gauge to find the smallest hole the mouse could squeeze through. His seven-minute video, above, became an Internet sensation.

The mouse tried many holes but gave up quickly if they were too small. What limits the mouse from squeezing through? It’s the size of his skull, not the size of his belly that stands in the way.

Near the end of the video a shrew appears. What limits the shrew?

(video by Matthias Wandel of woodgears.ca. click here for more of his videos)

Easter Lilies Are Poisonous To Cats

Easter lily (photo from Wikimedia Commons)

A flower that’s poisonous to one particular mammal …

If you have a cat, keep this plant far away from him. Easter lilies are extremely poisonous to cats.

Cat montage (image from Wikimedia Commons)

Native to Taiwan and the Ryukyu Islands of Japan, Easter lilies (Lilium longiflorum) are popular flowers at this time of year. Unfortunately every part of the plant is poisonous to cats: the flowers, the leaves, the stem, even the pollen.

Easter lilies are so poisonous to cats that if the pollen touches her and she grooms it away, it will poison her. The result is severe kidney failure.

The poisoning occurs quickly. Signs are evident within 6-12 hours of exposure. There is no antidote but immediate veterinary attention will improve the cat’s chance to live.

The Pet Poison Helpline recommends:

If your cat is seen consuming any part of a lily, bring your cat (and the plant) immediately to a veterinarian for medical care.

Pet Poison Helpline — Lilies Poisonous to cats

Do you have a dog? No worries. Easter lilies are not poisonous to dogs. This message only applies to cats.

Read more about cats at the Pet Poison Helpline. Read about dogs and lilies here.

p.s. Members of the Lilium genus are favorite foods for deer. I have not seen deer eating Easter lilies but I bet they love them.

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

Confuse A Meerkat

Did you know that meerkats have complex alarm calls?

Related to mongooses, meerkats (Suricata suricatta) live in colonies in southern Africa where their biggest enemies are jackals and eagles. Because they’re highly social they warn each other when danger is near. They even have special sounds to describe the source and threat level for each danger — combinations of “danger from the ground” or “danger in the air” with low, medium and high threat levels.

In this BBC Earth video, scientist Marta Manser tests the meerkats under various threat conditions. Everything goes as planned until she tests for “danger from the air!” by presenting them with a taxidermy jackal arriving by balloon.

“The results of that experiment were inconclusive.”

The meerkats looked up, confused. There is no alarm call for “flying jackal.”

(video from BBC Earth on YouTube)

Winning and Losing: Rabbits versus Virus

Invasive rabbit eating invasive rabbit-resistant plant in Australia (photo from Wikimedia Commons)

You would not think that something this cute could be a problem but European rabbits (Oryctolagus cuniculus) have plagued Australia for 160 years. After a century of recurring population explosions (think “plagues of locusts”!) scientists found a virus that kills only European rabbits. They introduced it in 1950 and it worked amazingly well for a while but the rabbit and the virus both evolved. Here’s their story.

Introduced for hunting in Geelong, Australia in 1859, the European rabbit immediately went feral and the population went out of control. Without any predators they covered most of the continent by 1910.

Range of the European rabbit; pink means “Introduced” (map from Wikimedia Commons)

Periodic population explosions, called rabbit plagues, became the norm. The rabbits eat everything. They devastate native plants, push out native animals, denude the countryside and cause dust bowls. In the photo below, at dusk, they are everywhere but probably not a plague yet since there’s still some grass.

So many rabbit holes. No trees or shrubs (photo from Wikimedia Commons)

Hunting and poisoning were ineffective.

Then in 1950 scientists found a virus in South America, called myxoma, that killed European rabbits. They released it in Australia (and in France) and it cut the rabbit population by 99%. Wow!

But a few rabbits lived and so did the virus. Science Magazine reports that “within a decade, rabbit numbers were on the rise again as some evolved resistance to this deadly infection and the virus itself became less deadly.”

This month, a new DNA study of both the rabbit and the virus shows that:

Rabbits on two continents evolved the same genetic changes to beat back the virus—before the virus itself changed and regained the upper hand. […and…] In the 1970s the virus developed a greater ability to suppress the rabbit’s immune responses. That change, as well as the natural emergence of another rabbit-killing virus, has caused populations to decline again.

— Science magazine, 14 February 2019

The arms race continues.

Don’t worry about the rabbits. They had another population explosion in 2004. At last count there are about 200,000,000 of them in Australia.

After all, they breed like rabbits.

For more information, read “Seventy years ago, humans unleashed a killer virus on rabbits. Here’s how they beat it” by Elizabeth Pennisi in Science Magazine.

(photos and range map from Wikimedia Commons. click on the captions to see the originals)

Kits in March

Pair of red foxes, Hain’s Point Golf Course, Washington, DC, Jan 2013 (photo from Wikimedia Commons)

January-to-February is mating time for red foxes in Pennsylvania and the Mid-Atlantic region.

Red foxes pair for life. They remain together from midwinter through summer. In autumn the foxes are solitary but reunite in winter for mating in January or February. Following a period of about 51 days, four to six young are born in late March or early April.

— Guide to the Mammals of Pennsylvania, p. 252 — Joseph F. Merritt

People usually don’t see foxes mating but Carly Lesser & Art Drauglis came upon this pair in January 2013 at Hain’s Point Golf Course in Washington, DC. Click here for another photo and scroll down to read the description.

If foxes mate in January, they have kits in March.

(photo by Carly Lesser & Art Drauglis at Wikimedia Commons; click on the caption to see the original)

Squirrel Appreciation Day


Eastern gray squirrel contemplates another raid on the bird feeders (photo by
Ken Thomas via Wikimedia Commons)

When January 21 is the third Monday of the month, an unofficial celebration falls on Martin Luther King Jr. Day (3rd Monday in January). Today is also Squirrel Appreciation Day (January 21).

Founded in 2001 by North Carolina wildlife rehabilitator Christy McKeown, Squirrel Appreciation Day is a good excuse to learn about squirrels:

How shall we celebrate Squirrel Appreciation Day? This one suggests that we give him a handout.

Grey squirrel, St. James’s Park, London (photo from Wikimedia Commons)

Pittsburgh’s squirrels will be grateful for extra food today. It was 2 degrees F this morning!

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

Truly Sunken Garden Trail

Evidence of beavers: downed trees and orange stump, Moraine State Park (photo by Kate St. John)

Last Saturday I tried to enjoy the Sunken Garden Trail at Moraine State Park but there were challenges along the way. The trail was very soggy, trees were down on the Short Loop, and part of the trail was under a few inches of water.

The flood is the work of beavers who backed up water in the wetlands (above) about 600 feet from the trail entrance (below).

Flooded Sunken Garden Trail, 5 Jan 2019 (photo by Kate St. John)

The Sunken Garden Trail is truly sunken here. Fortunately ankle-high muck boots were more than enough to keep me dry.

Be prepared for mud in this winter’s warm weather. And watch out for black-legged ticks. I got one on my pants after I bushwhacked around downed trees. They’re moving around out there, though in slow motion.

(photos by Kate St. John)