Monthly Archives: December 2011

Winter Trees: American Beech

Many of you already know the American beech tree (Fagus grandifolia) by its smooth, pale gray bark.  The bark is so pale that it stands out in the forest and so smooth that people sometimes carve their initials in it.  When you see a pale, gray, smooth trunk whose bark has carvings you know you’ve found a beech.

Mature beech trees are large, often 50-70 feet tall.  Their main trunk is relatively short then the tree spreads out in slender branches. They often grow in pure stands in the forest but this can be their undoing.  When one gets beech bark disease it spreads to the entire stand.  I’ve seen this sad outcome in the Gallitzin State Forest near the John P. Saylor Trail.  Like many tree diseases, this one is caused by an imported pest.

Small beeches are eye-catching in winter because they retain their leaves.  The pale, paper thin leaves become paler as winter progresses and they rattle and dance in the wind, drawing attention to their understory host.  Here’s a twig showing the leaves still attached in early winter:


Step closer and you’ll see that the twig is slender with alternate buds. Each one is nearly an inch long and angled away from the twig.  In this closeup you can see the bud has many scales.  Eight or more is diagnostic according to the Winter Tree Finder.


If you’re lucky you’ll find beech nuts under the tree.  The husks are 4-sided, spiny and burst open to reveal one to three seeds inside. These husks had two nuts each.


Beech nuts are good food for wildlife so you’re unlikely to find them in late winter…  But now you can easily find a beech.

(photos by Kate St. John)

Which Ones Are Cranes?

When people see a bird that impresses them they often tell me about it.  Sometimes they say, “I saw a crane” and I wonder… was it a crane or something else?   So I’ve made this conundrum into a quiz.

Which of these are cranes?  All of them?  Some of them?  Only one of them?  And which one is non-native?

(The answers are in the comments.)








(photos #1, #2 and #3 by Steve Gosser, photo #4 from Wikimedia Commons)

p.s. As usual I’ll wait to release comments from moderation so that early responders don’t give away the answer.


New Pair At Tarentum

For peregrine fans there’s happy news at the Tarentum Bridge today.

Back in the spring of 2010, a pair of peregrines nested here over the Allegheny River.  The female’s bands indicated she hatched at the Benjamin Harrison Bridge near Hopewell, Virginia in 2008, so we nicknamed her Hope.  The male’s bands identified him as a hometown bird hatched at the Cathedral of Learning in 2008, son of Dorothy and E2.

Unfortunately their nest must have failed.  It was never found and no young were observed.

In early 2011 Hope was still present at the bridge but she had no mate.  In late spring she disappeared too.

After many months without a peregrine sighting, Rob Protz saw one perched on the bridge yesterday afternoon.  He called Steve Gosser who came over with his camera.

After waiting and watching for 20 minutes, Steve checked the navigation beam and found a pair!  Here they are, the female above the male.  We don’t know their identity yet but I’m sure we’ll find out as birders and photographers flock to see and document them.

If all goes well, Tarentum will have peregrine nestlings this year.

Just when you thought winter was dreary, peregrines spice it up.  🙂

(photo by Steve Gosser)

Screech-owl on Camera

Good morning, “Hunter!”

That’s the nickname Bill Powers gave to this eastern screech-owl roosting in an owl box in his Murrysville backyard.

Bill is founder and CEO of PixController, a company that specializes in wildlife streaming webcams.  PixController set up the National Aviary penguin cam, the Gulf Tower and Pitt peregrine streaming cams, and the famous Lily The Bear cam which will be live again soon.

To demonstrate PixController’s expertise — and for fun — Bill has four streaming cameras set up at home.  Three are at ground-based feeding stations.  The fourth is in this owl box.


In October Bill noticed an eastern screech-owl roosting in his only owl box so he set up four more boxes in hopes of attracting a nesting pair in the spring.  At first the owl preferred box #1 but he didn’t roost there every day, though he sometimes left food for later consumption.  One day while the owl was away a squirrel built a nest over the owl’s cache and the owl never used that box again.

Now what?  Bill waited and watched until he knew which of the other boxes the owl like best.  Here’s how he figured it out:


After Hunter chose a new box, Bill installed the streaming webcam with an infrared light so we can see the owl even when the box is dark inside.  That’s why Hunter looks white in the webcam snapshots.

In today’s photo (at top), Hunter is facing the hole with his head bowed a little while he sleeps.  We see the top of his head and his back.  Reddish sunlight is brightening the box hole and two cracks at the front corners of the box.  Today Hunter brought a dark-colored mouse-y snack with him which he cached on the right.

Here are more pictures of Hunter sleeping, looking up and flying out.


You can watch Hunter live today (December 18) by clicking here or on the first photo above.  If you miss him today and he’s not there when you look for him, check back the next day.  Hunter doesn’t use this box every time.  He has other places to roost, but he’ll be back.


(photos by Bill Powers and PixController Wildlife Camera #4)

p.s. Click here to see all four PixController cameras on one page.

Why Gull Watchers Love Ice

The black-headed gulls at Moraine State Park are just two of the unusual gulls in the state this week.  Eastern Pennsylvania birders have reported Iceland and Glaucous gulls from the Arctic, a Franklin’s gull from interior North America, and lesser black-backed gulls from Europe.

These sightings are just the start of something big.

As winter comes to North America, gulls move to open water.  Those that breed in the arctic move to openings in the sea ice (called polynyas) but a few fly south and join the flocks of ring-billed and herring gulls at the coasts and on the Great Lakes.

In very cold years the Great Lakes freeze in February and the gulls move south.  That’s when they find Pittsburgh.

In early 2007 the weather was extremely cold for several weeks.  That February Pittsburgh’s rivers were treated to eight species of gulls at the same time. (We usually have two.)  In addition to herring and ring-billed gulls there were Bonaparte’s gulls and five Allegheny County rarities:

  • Iceland gull:  breeds in the Canadian Arctic Archipelago and on the coast of Greenland, winters on the coast of Greenland in arctic polynyas and sometimes on the coast of western Europe.
  • Thayer’s gull: breeds in the Canadian Arctic Archipelago and on the coast of Greenland, winters on the Pacific coast.
  • Glaucous gull: breeds on the arctic coasts of Canada and Greenland, winters on the Pacific and Atlantic coasts, Hudson Bay, and on the Great Lakes.
  • Lesser black-backed gull: breeds in Iceland, Britain and western Europe, winters on the coasts of Europe and Africa. A few spend the winter on the U.S. Atlantic and Gulf coasts.
  • Great black-backed gull:  an Atlantic coastal gull that breeds in northern Europe, Iceland, Greenland and along the Canadian and northern U.S. coasts. It’s a year-round resident in the southern part of its range.

There are photos of the 2007 gull event on Geoff Malosh’s website.

Last week ice began forming on western Pennsylvania lakes. Soon one, then two, black-headed gulls showed up at Moraine State Park.

Slowly the ice will thicken.  If the weather stays cold in January — really cold — Lake Erie will freeze and more gulls will come south to Pittsburgh.

Perhaps they’ll bring some rare friends with them.

That’s why gull watchers love ice.

(photo of a ring-billed gull on the ice at Pymatuning by Shawn Collins)

Jupiter’s Clock

In this day of cellphone GPS applications and vehicle navigation systems we forget that knowing exactly where you are on earth used to be a huge problem.  It was especially acute at sea where there aren’t any landmarks.

Until an accurate marine clock was invented in 1737 and became affordable in the 1780’s, seaman used the position of the sun, stars and planets to determine their location.  This worked well for north and south (latitude) but was impossible for determining east-west (longitude) because the earth rotates in that direction.

Shipwrecks occurred frequently, even under the best sea captains, and kings offered enormous prizes to the person who could solve the longitude problem.  Astronomers looked for a spot in the sky that behaved predictably and independently of the Earth’s orbit.

Galileo found an answer in Jupiter’s moons.

After he perfected the telescope in 1609, Galileo discovered the four largest moons of Jupiter.  He carefully logged their orbits and noted how often they disappeared behind the planet.  His records showed their orbits are so predictable you can tell time by them.  This was an answer to the longitude problem.

But it didn’t work at sea.  If you’ve ever viewed Jupiter through your binoculars you know that your heartbeat can make the planet jump.  No one could see the moons’ eclipses on a rolling boat deck.  However the method worked well on land with a tripod.

By 1650, the eclipses of Jupiter’s moons were so well documented that mapmakers used them to redraw the world.  Finally there were accurate land maps!  King Louis XIV of France reportedly complained that he was losing more territory to his astronomers than to his enemies (*).

Twenty-six years later Jupiter helped calculate the speed of light when Danish astronomer Ole Rømer discovered that the eclipses occurred sooner than expected when the Earth was closest to Jupiter and later than expected when Earth and Jupiter were furthest apart.  The difference is the speed of light.

Today Jupiter will rise at 2:00pm but his transit will go largely unnoticed.  His moons still keep accurate time but his role is eclipsed by our wristwatches, cellphones and satellites.


(Composite photo of Jupiter with its Galilean moons by NASA on Wikimedia Commons.  Click on the image to read how it was constructed.)


(*) This quote is from Dava Sobel’s book, Longitude: The True Story of a Lone Genius Who Solved the Greatest Scientific Problem of His Time, where I learned these facts about Jupiter.  I highly recommend her book, published by Penguin in 1995.  Click on the book link to find it on Amazon.

Winter Trees: Sugar Maple

Sugar maple buds (photo by Kate St. John)

This week’s tree is easy to identify by its twig.

The sugar maple (Acer saccharum) is a common tree in northeastern North America, prized for its wood, its brilliant fall foliage and its sap for maple syrup in the spring.

Like the white ash, the sugar maple is one of the few trees with opposite leaf buds.  If you look closely you’ll see that each pair of buds is rotated about 180 degrees from the previous set.  This keeps the tree in balance as the buds eventually become branches.

Sugar maple twigs are brown and slender and the leaf buds are brown and very pointy.  Test the tip of a bud with your finger and you’ll find it’s almost sharp!

A good hint for remembering the tree is to realize that the buds resemble upside down ice cream sugar cones.  “Sugar cones” on sugar maples.

Many trees are easy to identify by their bark but the sugar maple is not one of them.  The bark on young trees is stone-gray and smooth as shown below…


…but the bark on mature trees becomes furrowed with large flat scales that seem to vertically peel off the tree.  This makes for a lot of variation and can be quite confusing.  When I finally learned to identify sugar maple bark I called it “the bark that looks like nothing else.”  Not easy to explain.

If I’m stumped by the bark on a tall tree I always have one more trick up my sleeve.  I use my binoculars to examine the twigs.

Are the buds opposite, brown and pointed like sugar cones?  Sugar maple!

(photos by Kate St. John)

A Black-Headed Gull

A rare Old World gull showed up at Moraine State Park on Friday so a lot of birders made the trip to see him last weekend.  I was one of them.

Black-headed gulls are native to Europe and Asia though a small population crosses the North Atlantic to spend the winter in the Canadian Maritimes.  They are rare in the northeastern U.S. and extremely rare west of the Appalachians, so of course this bird attracted a lot of attention.

He was not a Life Bird for me but far more satisfying than the first one I saw at the exact same spot in December 1998.  Back then I was disappointed.  I was so new to identifying gulls that I knew I’d never be able to recognize him again without help.  He looked like a Bonaparte’s gull.

Just like a Bonaparte’s his head is not black in winter.  It’s only dark during the breeding season and then it’s not really black, it’s chocolate brown.  (Here’s what he looks like with a chocolate brown head.)   So much for his name.

The big difference between the two is that the black-headed gull has a red beak and red legs.  You can see these features easily in Cris Hamilton’s photos of a black-headed gull at (yes!) the exact same location in December 2008.  You can also see two faint lines that reach over his head from eye to eye and from ear to ear.  Someone remarked yesterday that the lines looked like he was wearing a set of headphones.

Black-headed gulls are halfway in size between Bonaparte’s and ring-billed gulls, the two North American species they typically hang out with.  Though they look like Bonaparte’s gulls their lifestyle is most similar to the ring-billed.  This puts them in an odd situation.  Should they associate with lifestyle cohorts or try to blend in?

This one chose to hang out with those who could help him find food.  Yesterday the ring-billed gulls chased him occasionally but otherwise rested peacefully, so he’s probably made a wise choice.  He’ll find a lot of food and make it through the winter.

I wonder if he’ll return next year.

(photos by Cris Hamilton)