Archive for the 'Mammals' Category

Jan 28 2009

Subnivean

Published by Kate St. John under Mammals, Weather

Subnivian mouse trails at my bird feeder (photo by Kate St. John)Last night it snowed then sleeted then rained.  It’s still raining, but so cold it’s turning to ice.

This morning I looked out the back window to see how the bird feeders were doing and found a network in the snow. 

What’s this?  I went out to investigate. 

All the lines originated from a hole under the sidewalk and grew outward like a tree toward the bird feeder.  Subnivean mouse trails! 

Subnivean means “under the snow.”  The mouse came out last night and tunneled to the feeders.  Under the snow he stayed warm and relatively safe from predators while he munched down on fallen seed.  Until today I didn’t even know he lived there because his trails in powdery snow aren’t as visible, but this morning the ice and rain made his tunnel roof transparent.  Way cool!

Many animals live under the snow all winter.   If you click on the photo, you’ll see a diagram of subnivean life in the arctic.  Here in Pittsburgh we don’t have snow cover all winter so the activity is intermittent. 

Want to hear more?  Here’s an audio story from New Hampshire Public Radio.

(photo by Kate St. John… using my cell phone.)

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Dec 06 2008

Acorn Plot

Published by Kate St. John under Mammals

Gray Squirrel (photo by Chuck Tague)I haven’t seen any interesting birds for days – not even flocks of crows.  The weather is colder, there are fewer birds and fewer hours of daylight.  Bummer.

So it piqued my interest when squirrels made national news. 

On November 30th the Washington Post reported there are no acorns this year in northern Virginia, Maryland and Washington, DC.  The next day NPR picked up the story

The total absence of acorns is puzzling scientists but not worrying them yet.  Oaks have natural boom and bust cycles.  However, having zero acorns puts the squirrel population in jeopardy.  They have far less to eat this winter and some will starve.  To prevent this people in Virginia have started feeding them store-bought hazelnuts!

But I couldn’t help wondering.  Was this just an “Inside the Beltway” phenomenon?  Are there no acorns anywhere in the U.S. or did squirrels become national news because there are no acorns in D.C.?  Is this a plot by the squirrels to get handouts all over the country even though there’s more than enough to eat everywhere else?  I decided to conduct my own research.

On my way through Schenley Park I stopped beneath a stand of oak trees and sifted through the leaves.  I found acorn caps and some rotten acorn pieces but nothing I’d call a “new” acorn.  Were these leftover acorns from last year?  Did the squirrels eat or cache all the good ones?   Did I accidentally find the dump where all the old leaf litter ended up?

I didn’t feel qualified to answer these questions so I turned to Google and they pointed me to the PA Game Commission website.  The Game Commission tracks the acorn crop because it’s such an important food for wild turkeys, deer and bears.   There I learned that acorns are indeed variable across the state this fall.  In Westmoreland County the Game Commission reported a good crop, in the Pittsburgh area it was rated “fair,” and in northcentral, northwestern and southcentral PA (closest to D.C.) it was considered “poor.”

So it isn’t a plot.  It isn’t a conspiracy.  Some squirrels are going to suffer.  Not mine, though.  They’re fat and sassy, eating from my neighbor’s black walnut tree.

(photo by Chuck Tague)

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Dec 02 2008

Deer Season

Published by Kate St. John under Mammals

White-tailed deer buck (photo by Joe Kosak/PGC photo)Yesterday was the start of Pennsylvania’s two week firearms deer season.  It’s the time of year when blaze orange is “in” and the crack of the rifle is heard throughout the land. 

There are probably as many opinions about deer hunting as there are white-tailed deer in Pennsylvania.   (That would be about 1.5 million.)  As a birder, I hope the hunters are successful because a good hunt protects songbirds. 

How can this be?

Persistent deer overpopulation results in a browse line, an area where nothing grows from the forest floor to the height of a deer.  This buck is standing in such an area.  You can tell because you can see straight through the forest behind him.  It makes for a nice clear picture, but not for biodiversity.

Deer eat plants.  When deer are too plentiful they reduce forest habitat and that in turn reduces songbird populations.  I first heard of this effect back in 1999 when I learned the results of a decade-long study by the Smithsonian Institution’s Conservation and Research Center (CRC)

The CRC maintained 12 study plots near Front Royal, Virginia:  six surrounded by deer exclosures to keep deer off the land, and six unfenced.  By comparing the presence and absence of deer, the study found that high deer density resulted in two impacts on birds: direct competition for food (affecting wild turkeys) and destroyed understory habitat (affecting songbirds). 

For songbirds to survive they need cover.  When the understory is destroyed, their populations decline and nest survival falls to zero.   In the CRC study, understory birds such as hooded warblers, eastern towhees, and wood thrushes increased dramatically when deer were excluded.   The veery population doubled!  Even birds who nest in trees – rose-breasted grosbeaks, cerulean warblers and scarlet tanagers – benefited from a reduced deer population.

Sadly many of these songbirds are in decline.  Deer, on the other hand, are prolific and can double their population every two to three years.  Even with hunting and car accidents southwestern Pennsylvania’s deer population is stable, even growing in some locations.

It’s possible to have both deer and songbirds but only if the deer herd is kept in check.  So I’m glad it’s hunting season. 

 ——

If you’re going out hiking or birding, don’t forget to wear blaze orange!

For further reading and videos about Pennsylvania deer management see the PA Game Commission website on white-tailed deer.   If you want to read about a huge deer problem see the Fairfield County (Connecticut) Municipal Deer Management Alliance and their section on bird impacts.

(photo by Joe Kosack/PGC photo, courtesy of the Pennsylvania Game Commission public photo gallery)

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Nov 24 2008

Winter Hike

Published by Kate St. John under Hiking, Mammals, Plants

Winter at Moraine State Park (photo by Kate St. John)I like to hike in winter when it’s not too cold.  The woods are open after the leaves have fallen and I can see new places to explore.  Even better, I can go off trail without worrying I’ll get lost because I can follow my own tracks in the snow back to the car.

Yesterday I explored Porters Cove at Moraine State Park.  Most of the time I stayed on marked trails (shown here) but I was tempted to follow someone else’s footprints into the woods.  Where were they going?  And why?

The tracks looked to be a day old and they went both ways – out and back – so I knew I wouldn’t encounter the person if I followed them.  There’s no hunting on Sundays but I put on my blaze orange vest and hat just in case and set off.

From the start the tracks wove in and out.  The man was hunting.  Perhaps he too was tracking something but what I could not tell.  His wanderings were tiring me so I made my own straight trail.  That’s when I discovered something the man didn’t see – a coyote’s den in the hollow of a huge old oak.  The animal had left the den at least a day before the man walked by.  Eastern coyotes survive by carefully avoiding human contact.

As I examined the coyote’s tracks I smelled a skunk.  What’s this?!  Just a patch of skunk cabbage I’d inadvertently crushed underfoot.  Skunk cabbage not only survives the winter but is one of the first to sprout in the spring because it can generate inner temperatures 35 degrees warmer than the air.  Each plant in this patch had melted the snow around it.

I resumed the hunter’s trail.  At this point he was walking straight through the woods and had made the trip twice.  I paused at the edge of a copse of trees.  For some reason I didn’t want to proceed.  I looked ahead and saw his tree stand erected for deer season.  Best not to go near it.  Interesting that my intuition said “stop” before I got there.

On the way back I took a detour to walk near the lake.  As I approached I heard a hissing, pinging sound.  The lake had started to freeze and a thin layer of clear ice rolled on top of the waves.  The ice was “singing.”

Way cool.

(photo by Kate St. John)

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Oct 20 2008

White Falcon, White Wolf

Gyrfalcon (photo from the PBS series Nature. www.pbs.org/nature)If you’re a falcon fanatic like I am you won’t want to miss White Falcon, White Wolf,  the season opener of PBS’s Nature, starring the largest falcon on earth.

The show tells the story of the brief arctic breeding season, focusing on a family of gyrfalcons and a pack of arctic wolves

The setting is the stark landscape of Ellesmere Island, the northernmost point in Canada.  It is summer, but only for three short months.  In that time all the arctic creatures must court and mate, give birth and raise young.  The challenge is in the timing.  If the food supply is not ready or not adequate, the young starve.

The photography is stunning and required lots of patience and stamina.  I can barely imagine the days – maybe weeks – the photographers must have spent in a blind on a neighboring cliff.   The sun never sets during the arctic summer so how did they avoid detection, not only by the gyrfalcons and wolves but by the many other birds and animals in the film?

Don’t miss it!  The show premieres this Sunday, October 26 at 8:00pm.  In the Pittsburgh area watch it on WQED-13, or if you have HDTV on WQED-HD.  If you live outside WQED’s broadcast area, check your local PBS station schedule to be sure it’s at 8:00pm.  

(photo from White Falcon, White Wolf)

p.s.  The gyrfalcons are beautiful, but for sheer cuteness watch for the arctic foxes.

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Oct 02 2008

Unscented

Published by Kate St. John under Mammals

Mario Le Pew, skunk, meets Innes Donahue (photo by Maren Cooke)Pictured here – safely “deodorized” and in a cage – is the only docile animal that strikes fear in my heart. 

It’s been a month of skunks for me, beginning on the first night of our Maine vacation.  After 9 hours of sitting in airports, on planes and buses, we arrived at our hotel.  Though it was 9:00pm we needed to stretch our legs so we took a walk around the parking lot. 

At the wildest corner of the parking lot – if a collection of shrubs can be called “wild” – I smelled a hint of something unpleasant.  Fox?  We took a few more steps in the dark.  Is that a black cat at the edge of the lawn?  No!  A skunk!  I grabbed my husband’s arm and we jumped back a step.  There were two skunks near the trees and one of them was stamping his feet.  We were out of there!

A similar thing happened the next night – different place, different time, another skunk in the dark - so when the Animal Rescue League Wildlife Center brought a disarmed skunk to the Group Against Smog and Pollution picnic last Saturday, I was intrigued.  Here was a skunk I could get close to.  Here’s what I learned:

  • Skunks have good senses of hearing and smell (imagine!) but they cannot see beyond about 10 feet.
  • They have muscles near their anal scent glands which allow them to accurately spray 7-15 feet.
  • Their scent gland is empty after 5-6 sprays and it takes 10 days to refill so they conserve the spray by warning you with foot stamping, hissing and holding their tails high.  (Thank heaven!)
  • Even when a skunk’s scent glands are removed the scent is still part of them, though fainter.  If you handle a skunk, you will pick up that faint scent on your hands and clothes.  After a while you won’t notice it – but members of your carpool will.
  • Skunks can carry rabies for five or six generations without exhibiting symptoms.  That’s why pet skunks must come from breeders, not the wild.

And how does this relate to birds? 

It turns out that other than humans, the skunks’ only predator is the great-horned owl … because the owl doesn’t have a sense of smell!

(Thanks to Maren Cooke for the picture of “Mario Le Pew” from the ARL Wildlife Center getting acquainted with her daughter, Innes Donahue, at the GASP picnic.)

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Sep 07 2008

The Chicken Fox

Published by Kate St. John under Mammals

Acadia National Park is always a good place to see wildlife.  The one species we’re sure to see is the red fox. 

Introduced to the United States by British settlers who enjoyed fox hunting, the red fox quickly established itself in the niche of medium-sized mammalian predators.  In Maine as everywhere they’re generalists, hunting for prey the way cats do by stealth and pounce but willing to eat roadkill if the opportunity arises.

That’s how we saw a vixen and kits one evening, eating a dead fawn by the side of the road.  Because of the position of the fawn, the kits were in danger of being hit by a car so I stopped and used my hiking stick to push the roadkill into the ditch.  This must have worked as there was no hint the next day that any kits had been hurt.

One night at the inn we were awakened by eerie barking – a cross between a cat’s yowl, a dog’s bark and a cry of pain.  It was a fox claiming his territory but it gave us the creeps.  We were very glad when he shut up.

Our best encounter was with The Chicken Fox.  No, he didn’t kill domestic chickens.  Someone in the neighborhood felt sorry for him and provided supermarket meat.  The Chicken Fox became single-minded and fearless about retrieving his handout and would trot across the backyard every afternoon on his way to the stash.  We knew what he ate because he would carry the boneless, skinless chicken breast back to the woods.

I think the chicken handouts prolonged his life.  He looked worn out and mangey in his final year but still showed up for his daily meal.  The Chicken Fox is gone now, but his descendants live on.

(photo by Chuck Tague)

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Jul 20 2008

City raccoons

Published by Kate St. John under Mammals

Birds are pre-empted by mammals today because…

Early this morning as I drank coffee on the front porch I heard an unusual scrabbling noise at the base of my neighbor’s blue spruce.  A raccoon was running up the tree!

Raccoons living near people is no surprise, but you rarely see them during the day.  I hated to see a coon at that tree because it’s loaded with bird nests so I made my best cat-hissing sound.  Stupid me.  The raccoon got scared and climbed even higher. 

I went inside to get my binoculars and returned quietly.  After a while four raccoons came out of the tree and ran across the street to Magee Field.  At the edge of the park they nosed around for fruit and considered crossing the street again.  I could follow them with my ears as carolina wrens, blue jays and robins announced their every move.  

I got a laugh when the tom cat who rules our neighborhood noticed the raccoons and charged across the street at them.  The coons’ hair stood up on the backs of their necks and they all reached for a tree to climb.  The cat stared them down and left.

There were certainly determined to cross the street.  At one point I was surprised to see three sets of eyes peering out from under my car.  I cat-hissed again.

Four!  All of them were adult sized so they must be this year’s grown-up kits and mother on the prowl for food.  Yow.  If these coons reproduce next winter the neighborhood will be overrun!

Chuck Tague took this photo of a raccoon family in Florida.  They’re everywhere!

 

p.s.  Aha!  Now I know why they wanted to come over here.  It hasn’t rained for days and I have a bird bath in the backyard that sits on the ground.  After I finished this blog I noticed the bird bath was empty but damp.  Thirsty raccoons.

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Jun 14 2008

Food for thought

Published by Kate St. John under Mammals

Eastern Gray Squirrel (photo by Chuck Tague)This morning at breakfast I watched a gray squirrel mosey along the garden wall, pick a ripe strawberry and begin to munch on it. My black cat crouched at the window and muttered, but the squirrel knew the cat could not get out. He nonchalantly ate half the strawberry and dropped it on my deck.

Annoying! He ate only half and then he littered.

And what was he doing eating fruit?

It turns out that gray squirrels specialize in nuts but they also eat fruit, insects, bird eggs and nestlings.

That explains the scuffle I saw yesterday. I found a squirrel running out of a tree hotly pursued by a pair of robins. The robins meant business and were trying to peck him. I figured they were defending their nest so I tried to help by chasing the squirrel away. I have no idea if that was effective.

It’s a difficult time for nesting birds. The nuts aren’t ripe yet and the squirrels are hungry. The only mitigating factor is that the red-tailed hawks are hungry too… for squirrels. 

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Apr 22 2008

Close Encounters

Louisiana Waterthrush (photo fromChuck Tague)

If you want to see birds up close, go to where the birds are, sit down on the ground and eat your lunch. 

I’m not kidding!  But first you have to understand the context.

I was prepared for rain last Sunday so I was wearing a big floppy hat and a yellow rain slicker over my backpack.  This gave me a big head and a hunchbacked look.

I was in one of the best spring birding places in Pennsylvania:  Enlow Fork, literally the “Enlow Fork of Wheeling Creek” which forms the border between Washington and Greene counties, almost in West Virginia. 

I was the only person there – even the fishermen weren’t on the scene – and the sky looked ominous.  It rained off and on.

I moved slowly.  The hungier I got, the slower I moved.  When it rained at lunchtime, I took shelter at the second bridge and opened my crinkly lunch bag.  Imagine a bird’s perspective:  a creeping yellow hunchback with a floppy green head making crinkly sounds.  How intriguing!

Zip!  A yellow-throated warbler flew past my left shoulder, stopped on the bridge for a quick glance and he was gone.

Chink!  A Louisiana waterthrush, pictured above by Chuck Tague, perched across the creek and sang a challenge to me.  How dare something so weird sit in his territory!

The rain came down harder.  I crept into better shelter and the Louisiana Waterthrush flew up for a better look.  Perched on the bridge just above eye level, he took a bath in the rain.  Awesome!

Bonus sightings:

Muskrat (photo by Chuck Tague)While standing above a small pond, I saw a muskrat swim by carrying leaves.  He went back and forth several times without noticing me. 

Finally I couldn’t stand the suspense.  Animals often recognize a human voice faster than a human shape, so I spoke to the muskrat.  “Hello, Muskrat.”  He froze immediately, feet splayed out, but he kept drifting forward.  Ha!  He’s not hidden with those waves moving out ahead of him! 

Chuck Tague tells me muskrats are oblivious.  This one proved it.

Virginia Bluebells blooming at Enlow Fork, April 20, 2008

And finally, though Enlow Fork is known for its wildflowers the rain kept most of them closed.  Not so with the Virginia Bluebells as you can see in this photo from my cellphone.

So if you want to see birds up close, put on a big floppy hat, and sit in the rain.  It works for me!

 

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