Archive for the 'Mammals' Category

Jul 08 2015

Too Many Ticks? Hire a Possum

Virginia opossum (photo by Drcyrus from Wikimedia Commons)

Pennsylvania won an award again though there’s no reason for applause.  For the third straight year we lead the nation in reported cases of Lyme disease.

One could argue that we won because Pennsylvania is a big state with a large population, but we also have too many black-legged ticks, too many tick hosts that carry Lyme disease (mice), and too many deer carrying ticks long distances to other locations.  Black-legged ticks are now present in every county in the state.

What to do?  In April I wrote about the many effective ways to reduce ticks around your house and protect yourself outdoors.  But here’s an unconventional solution.  Get yourself a ‘possum.

Like all mammals, Virginia opossums pick up ticks in their travels but the good news is that they don’t carry Lyme disease and they groom so meticulously that ticks don’t stay on them for long.  In fact, when a possum finds a tick on its body, it eats it!

Weird as they are, possums have some advantages.  They consume up to 5,000 ticks in one season and are practically immune to rabies and venomous snakes.

So as we do our best to combat Lyme disease — especially in May through July when black-legged ticks are so hard to see in their tiny nymphal stage — remember that having a possum in your yard is a good thing.

Too many ticks? Hire a ‘possum!


(photo by Drcyrus from Wikimedia Commons. Click on the image to see the original)

4 responses so far

Jul 01 2015

Mr. Mouse Went A-Courting

Published by under Mammals

House mouse (photo via Wikimedia Commons)

House mouse (photo from Wikimedia Commons)

Did you know that male mice sing to attract the ladies?

We can’t hear their songs because they’re way too high for our audio range but each species has its own song and they vary the tunes to fit the social setting.

I learned about this in April’s Audubon news when they highlighted Duke University’s research into mouse songs.  The article included this video of two mouse songs with the audio track digitally lowered so we can hear it.

First a researcher places fresh female urine in the male’s enclosure. Mr. Mouse can smell her but can’t see her so he sings a loud and complex song.  Next they put a female in the male’s enclosure.  When he finds her (why does it take so long?) he snuggles up and sings a softer, simpler song.

What do the lady mice think?  When placed alone in an enclosure with a speaker playing male songs, most females stay close to the speaker when the complex songs play.  Perhaps those songs say “Come hither!”

Click here to read more in Audubon Magazine.


p.s. We can’t hear mice sing at 50 kHz, but cats can. 😉

(video from’s Vimeo site. photo of a house mouse from Wikimedia Commons; click on the image to see the original.)

The title is a reference to “Frog Went A-Courting” in which Frog sings to woo Miss Mouse.

4 responses so far

Jun 26 2015

Not Exactly Squirrel Proof

Published by under Bird Behavior,Mammals

Red-bellied woodpecker and chipmunk at squirrel-proof bird feeder (photo by Jonathan Nadle)

Red-bellied woodpecker and chipmunk dining at a squirrel proof feeder (photo by Jonathan Nadle)

Jonathan Nadle’s neighbor has a squirrel proof bird feeder but it doesn’t keep out all the squirrels.

A small member of the Sciuridae (squirrel) family squeezes though the mesh and helps himself to seeds.

A lot of birds won’t visit while the chipmunk’s there — did you know chipmunks eat bird eggs? — but the red-bellied woodpecker has nothing to fear. His long sharp bill is a formidable weapon.

Red-bellied woodpecker and chipmunk coexist at the squirrel-proof bird feeder (photo by Jonathan Nadle)

(photo by Jonathan Nadle)

“Squirrel proof” might not work for chipmunks but at least it keeps out Pennsylvania’s largest member of the squirrel family –> groundhogs.


(photos by Jonathan Nadle)

p.s. Gray squirrels are in the Sciurinae (tree-based) subfamily. Groundhogs and chipmunks are both in the Xerinae (ground-based) subfamily and members of the Marmotini tribe (marmots!).

2 responses so far

Jun 18 2015

TBT: Food For Thought

Gray squirrel (photo by Chuck Tague)

Gray squirrel (photo by Chuck Tague)

Why are songbirds angry at squirrels?

On Throw Back Thursday (TBT), here’s some Food For Thought from June 2008.


(photo by Chuck Tague)

One response so far

Mar 31 2015

More Deer, Less Moose

Moose and deer (both photos from Wikimedia Commons)

What happens when the interval between spring thaw and leaf out gets longer?  Fifty years of detailed observations in New Hampshire’s Hubbard Brook Experimental Forest tell the tale.

In New Hampshire, where snow covers the ground all winter, spring thaw is a welcome event that finally exposes the soil.  Weeks later after lots of warm air and sunshine the trees leaf out.  In between these two events the sun warms the soil, the plants emerge, and wildflowers bloom.

Hubbard Brook Experimental Forest has kept detailed records of temperature, precipitation, snowpack, plants, animals, birds and invertebrates for more than half a century. An analysis of the data, published in BioScience in 2012, showed that the forest is getting warmer and wetter and the interval between spring thaw and leaf out has increased by 8 days.  Climate change is separating spring’s above ground (air) responses from the soil responses.

In the post-thaw interval severe cold events freeze the exposed soil and kill plant buds and invertebrates. This threatens some deciduous trees (yellow birch and sugar maple in New Hampshire) and birds find fewer invertebrates when they return from migration.  The record shows the mix of plants and animals is changing.

There are even changes in large animals.  For the past 50 years the snowpack has declined, an outcome that favors deer over moose and that seems to be happening at Hubbard Brook.

More deer, less moose.  If you write it down now you can see the trend later.

Read more here in Science Daily, December 2012.


p.s. It should be “More Deer, Fewer Moose” but I am quoting one of the articles and happen to like the ungrammatical juxtaposition.

(photo of moose by Ronald L. Bell, USFWS via Wikimedia Commons.  Photo of deer by josephamaker2018 via Wikimedia Commons. Click these links to see the original images.)

2 responses so far

Mar 05 2015

Cover Your Ears

Published by under Mammals

Opossum in winter (photo by Cris Hamilton)

After Tuesday night’s high of 49oF we’re headed for 1oF tonight.  Everything that lives outdoors is in for a huge surprise.  Opossums, in particular, should watch out.

Opossums’ thin ears and naked tails are prone to frostbite.  Though normally nocturnal, they come out during the day when they’re hungry.  That’s how Cris Hamilton photographed this one at her bird feeders in early 2011.

And yes, her backyard possum had a hard winter that year.  His ears are pink because they’re frostbitten.

Opossums! Cover your ears tonight … or stay indoors.


(photo by Cris Hamilton)



One response so far

Mar 03 2015

A Mimic On Two Levels

Published by under Mammals

Margay cat or "tree ocelot" (photo from iStockphoto/Jeff Grabert via Science Daily)

One glance tells you this wild cat’s fur mimics his dappled forest habitat.  Amazingly, he can mimic on another level, too.

The margay (Leopardus wiedii) is a nocturnal feline of Central and South America that looks like a small ocelot.  Longer and lighter weight than a pampered house cat, he weighs 5.7-8.8 pounds and is 32-51 inches long (including his long tail!).

The margay lives in trees in the tropical forest and rarely comes to the ground because he doesn’t need to.  He’s so well adapted to climbing that his ankles rotate 180 degrees so he can walk down trees head first.  He can also leap 12 feet straight up to capture small mammals, birds, lizards and tree frogs.

In Brazil one mammal on the margay’s menu is the pied tamarin (Saguinus bicolor), a small primate the size of a squirrel.

Pied tamarin (photo by Whaldener Endo via Wikimedia Commons)

Native Amazonians have long known that the margay can mimic the sound of this monkey, but it wasn’t recently that the rest of the world found out.

In 2005 researchers watched a group of eight pied tamarins feeding high in a ficus tree when a margay, hidden in dense liana vines, tried to lure them by mimicking the call of a tamarin pup. A tamarin “sentinel” climbed down to investigate the noise, then started to warn the rest of the group, but four other tamarins were so confounded by the baby tamarin sound that they too climbed down to see.  At that moment, the margay emerged from the foliage, walking head first down the trunk, and jumped toward the monkeys. Realizing the ruse, the sentinel screamed an alarm and all the tamarins fled. (*)

The Wildlife Conservation Society reported this incident in 2010, the first recorded instance of a wild cat species in the Americas mimicking the calls of its prey.

Pied tamarins are endangered and the margay is “near threatened.”  Large primates (humans) have killed the margay for its fur and the pied tamarin for food.  We’re lucky to have heard of this mimickry trick before it disappeared.

Read more about it here in Science Daily.


(Margay photo from iStockphoto/Jeff Grabert via Science Daily. Pied tamarin photo from Wikimedia Commons/Whaldener Endo, Creative Commons license. Click on the images to see their originals.)

One response so far

Feb 16 2015

Tracks In The Snow

Published by under Mammals

Deer mouse and squirrel tracks in the snow (photo from Wikimedia Commons)

Don’t feel trapped indoors on this cold bank holiday.  There’s snow outside and there are animal tracks in it!   Identify the tracks and you can read their story.

You don’t have to stand out in the snow to identify them.  Bundle up and take a camera or cellphone and a ruler.  (The ruler is important! In your photos it will show you the size of the paw print and the distance between prints.)

Run out to the feeder, set the ruler near some tracks and take a bunch of pictures.  Then come inside and identify the tracks at your leisure. Here are some tracking guides to help:

Using Dorcas Miller’s Track Finder booklet, I identified the squirrel tracks beneath my bird feeder. It helps that I saw the squirrels make them.  😉


(photo of deer mouse tracks(across the middle) and squirrel tracks (in the back left corner) from Wikimedia Commons. Click on the image to see the original by Jomegat.)


One response so far

Jan 19 2015

Non-Verbal Communication

Published by under Mammals

Emmalina in the Victory Zone (photo by Kate St. John)

Today’s blog post is about animal behavior, though not about a wild animal.

I am always fascinated by birds’ and mammals’ ability to communicate without complicated language.  Gestures and eye contact are often so effective that the one who sees the look or gesture knows exactly what to do.  I’ve noticed this on the webcams among nesting peregrines and eagles who don’t have language but certainly get the point across — often with just a pointed look in the youngster’s direction.

Can gestures and eye contact achieve communication between species?  I think so.

Shown above is the animal I watch most closely.  Her name is Emmalina (or Emmy or Emmaline).  Though domesticated her heart is wild.

Emmalina makes a few sounds I understand but the rule in our house (my rule) is that meowing doesn’t get you anywhere.  If you want a treat, “sit pretty” and silently in the Treat Zone (where she’s sitting right now) and you’ll get one.  If I don’t notice her sitting there she makes a very faint “mewp” to get my attention and then sits silently.  I congratulate myself that I’ve trained her to do this.

We’ve always fed our cats in the basement, just down the kitchen stairs.  Emmalina is 8 years old and she knows the routine.  She usually runs downstairs ahead of me to be in place when her dish arrives, but last week she started to run away when I went downstairs.  She wouldn’t come down and she wouldn’t eat anything in the basement — not her canned food, not the dry food.  I began to wonder if she was ill.  (Nope! I could tell she was hungry.)   Would I have to call the Cornell Animal Behavior Clinic to figure out what was going on?

Last Friday the problem was solved in such an amazing way that it generated this open letter to Cornell.

Dear Cornell Animal Behavior Clinic:

The training program was successful at last.  After two weeks of non-verbal instruction the humans have figured out that I want to eat upstairs.  It was worth refusing a week’s worth of dinners in the basement.

Relieved and vindicated,

Emmalina St. John

Notice her dish in the Treat Zone now!  She says the basement floor is too cold in winter.

Non-verbal communication does work … eventually.


(photo by Kate St. John)

p.s.  Cornell Animal Behavior Clinic is a great resource.  As part of the Veterinary College they have extensive experience with companion animals and can tell you exactly what the behavior means and how to address it.  Don’t hesitate to look them up if you have a behavior problem with a dog or cat.

13 responses so far

Jan 02 2015

First Day Findings

Published by under Hiking,Mammals,Plants

Wingstem seeds, North Park, 1 Jan 2015 (photo by Kate St. John)

What can you find outdoors on January 1 in Pittsburgh?  Nine intrepid naturalists from the Botanical Society of Western Pennsylvania and Wissahickon Nature Club hiked at North Park to find out.

Though yesterday was quite sunny the temperature hovered just below freezing and the wind was strong.  We bundled up to look at seeds, trees, dry weeds, and birds.

Above, a wingstem seed pod looks just like a dried version of the flower’s central disk.  Below, in the thicket we found juncoes, titmice and chickadees … and then changed our focus to identify the trees.
Participants on the New Year's Day hike at Irwin Rd (photo by Kate St. John)

Dianne Machesney found this still-red scarlet oak leaf.  I held it to take its picture.
Scarlet oak leaf, 1 Jan 2015 (photo by Kate St. John)

The ground wasn’t frozen but the creek had glimmering white ice.

Ice on Irwin Run, 1 Jan 2015 (photo by Dianne Machesney)

(photo by Dianne Machesney)

After the hike, some of the party drove up Pearce Mill Road to check on the beaver dams on the North Fork of Pine Creek.

The beavers were snug in their beds while we braved the cold.

Beaver dam on the North Fork of Pine Creek (photo by Dianne Machesney)

(photo by Dianne Machesney)


(photo credits: wingstem, hikers and oak leaf photos by Kate St. John.
Creek ice and beaver dam photos by Dianne Machesney

One response so far

« Prev - Next »