Yearly Archives: 2012

Why So Many Robins?

Bird Behavior, Trees

Why are there so many robins in Pittsburgh right now?  Food.

What are they eating?  You’re looking at it.

These are Bradford callery pears, the fruit of a popular small street tree that has pretty white flowers in early spring.

This particular cluster is from a row of trees next to the Pittsburgh Board of Education on Bellefield Avenue but I’ve found Bradford pears at Carnegie Mellon, at Pitt, on neighborhood streets, in mall parking lots … they’re everywhere.

And they’re imported. Callery pears are normally thorny trees.  Native to China they were first brought to the U.S. in 1918 as an experiment in producing rootstock for pear orchards, but that didn’t work out.  Instead, one of the experimental trees grew without thorns, was recognized for its ornamental value and became the “Bradford” cultivar.  By 1982 Bradford callery pears were the second most popular landscape tree in the U.S.

As usual with non-natives, they are easy to point out in late November because they still retain their leaves.  Before they fall the leaves turn yellow, orange and then deep red, another reason for the tree’s ornamental value.  In spring the flowers bloom earlier than our native trees.  (I happen to think the flowers smell bad but most people don’t notice it.)

Since their introduction, callery pears have become naturalized and in some places invasive.  It’s easy to see how their seeds spread when you watch a flock of birds feasting on them.  This year the fruit is especially prolific and so are the robins and starlings.

As soon as the fruit is gone and the ground is covered with snow, the robins will go.  Until then, it’s a party.

(photo by Kate St. John)

New Series

Musings & News, Tenth Page

As usual, winter is a slow time for observing nature so my blog ideas are pretty thin. However, your encouragement on my Bird Anatomy series (20 Nov 2009 to 25 Feb 2011) has inspired me.

This Friday I’m going begin a new series called Tenth Page.

Though it’s loosely based on bird anatomy, Tenth Page is named for its subject matter.  My rule is that I must open Frank B. Gill’s Ornithology at a page number evenly divisible by 10.  Whatever is on that page will be fodder for a blog.

I’ve already checked all the tenth pages in my copy of the book and discovered that there are 3 blanks in the #10-series.  Aha!  Those will be wildcard subjects in which I can pick any old page I please.

And I won’t be predictable.  That would be boring.  Not 10, 20, 30 for me!  To keep myself interested I’m more likely to dip in at random and choose a tenth page that inspires me.

As a result, you won’t be able to guess my subject by reading the book — and neither will I.

Stay tuned for Tenth Page, coming this Friday.

 

(photo by See-ming Lee via Wikimedia Commons. Click on the image to see the original)

 

p.s. The photo above has a series of its own.  Taken by See-ming Lee at Vinegar Hill, New York, NY on 30 Dec 2007, it’s been posted to Wikimedia Commons for use in a series of blogs.  Click on the image to see the original photo and the list of blogs that have used it.  (Mine is there too.) Pretty cool!

p.p.s.  On the Bird-thday blog Peter and Stephen suggested I write about bird calls.  Be watching for bird calls sprinkled throughout the year.

The Sound Of Frozen Water

Water and Shore

On Saturday the featured Media of the Day at Wikimedia Commons was this audio clip of the “singing” sounds of an iceberg.

Click on the player and you’ll hear amazing squeaking and groaning noises.  At first you’d think it was the sound of a boat but soon you hear thumps,  snaps and grinding as the iceberg shifts.

 

 

If you don’t want to listen to all 4+ minutes of iceberg sounds, begin playing the clip and let the audio bar fill.  Then click on the bar at the 3/4 mark to hear some amazing roars and sawing noise.

Who knew that water could sound so industrial!

(audio from Wikimedia Commons.  photo by Kim Hansen from Wikimedia Commons. Click on the image to see the original which was Picture of the Day on 29 June 2008.)

Swans!

Migration, Water and Shore

…Specifically, tundra swans!

Last week we were blessed by the sights and sounds of gorgeous white birds on their way from Canada’s Arctic coast to Chesapeake Bay and beyond.

Most of them didn’t stop but that didn’t matter.  They’re beautiful in flight.

Marcy Cunkelman had her camera ready as the flocks flew over her house.

Bye bye, swans.

(photos by Marcy Cunkelman)

About Rooks

Beyond Bounds, Crows & Ravens

When five rooks came to celebrate my blog’s anniversary last week they piqued my interest because we never see them in North America.

Rooks are Eurasian relatives of crows, found from Ireland to Japan.  At a distance they look like American crows with very long beaks but this is an illusion.  Their beaks look long because the skin on their faces is naked and matches the beak color.

Close up the skin is obvious and a bit disturbing if you’re not used to it.  When they perch with wings hunched and feathers puffed they resemble the Grim Reaper.  Actually, artists probably chose rooks as their model for the Grim Reaper and not the other way around.

Like blue jays, rooks can store food in their throat bags, then carry it elsewhere.  The throat becomes distended as you can see briefly in the video above.

Rooks are more social than their American relatives.  They nest communally in the treetops in collections called rookeries.  In North America we have no rooks but our herons use the same nesting technique so we call their groupings heron rookeries.

Like crows, rooks are curious and really smart but this can make them annoying.  To a rook, it’s normal to make holes to hide food but this is a liability if you keep one indoors.  Fortunately, few people do.

Early this year I enjoyed reading Corvus: A Life With Birds by Esther Woolfson in which she tells the story of her rook named Chicken, a very smart and engaging bird, but I agree with the Daily Mail which said, “Yet perhaps the best measure of Woolfson’s candidacy for sainthood is the permission she has given Chicken to dismantle the plaster and lath on her hallway wall so that the rook has its own food storage space.”

…You see what I mean…?

Smart… but not good pets.

(video by Goldfinch Garden on YouTube)

A Lasting Impression

Beyond Bounds

This feather is 150 million years old, give or take a millenia.

Found in Solnhofen, Germany and documented by Hermann von Meyer in 1861, the Urvogel Feather (“Original Bird” Feather) caused a sensation for several reasons:

  • It was the first and oldest single feather fossil ever found.
  • It was paired and described with the first feathered dinosaur, Archaeopteryx lithographica, a species that displayed characteristics of both dinosaurs and birds.
  • It was discovered only two years after Charles Darwin published The Origin of Species and was hailed as evidence of evolution.

Feather fossils are rarely found because they must form in finely grained material in an anoxic environment.

Back in the Jurassic period when the Urvogel feather fell from an Archaopteryx’s wing, Bavaria was a group of tropical islands.  The feather landed on water — probably still attached to the dead dinosaur — and eventually settled to the bottom in a “dead zone” where the lack of oxygen prevented it from decomposing.

The sediment became limestone so finely grained that it led to the invention of lithography in 1796.  These quarries produce high quality stones for print-making and uncover many fossils.

Eventually 11 fossils were identified as Archaeopteryx, a raven-sized feathered dinosaur shaped like a magpie.  In 2011 scanning electron microscopy revealed that some of its feathers were black.

Naturally “Archy” has generated a lot of discussion over the years — from analyses placing him in the trajectory of dinosaurs to birds, to arguments denouncing evolution that said his fossils were fake.  (Those arguments were easily debunked because their authors misunderstood geology.)

150 million years since it died, 150 years since it surfaced, the Urvogel Feather has made a lasting impression.

(photo taken at Museum für Naturkunde in Berlin where the Urvogel Feather was on display for its 150th anniversary.  Click on the image to see the original on Wikimedia Commons)

Hazy Inversion

Weather & Sky
View from the Allegheny Front Hawk Watch, 11 Nov 2012 (photo by Kate St. John)

14 November 2012

Three weeks ago I wrote about radiation fog and inversions.  We had another inversion recently, this time without fog.

Here is the view last Sunday from the Allegheny Front Hawk Watch.  It looks like a bad picture of beautiful scenery but it’s actually a good illustration of a hazy inversion.  Notice how the near trees are colorful and Wills Mountain, 10.5 miles away,  is bland and washed out.  You can’t see the fire tower on Kinton Knob.  The colors are cancelled by bad air.

This was a classic temperature inversion but the first time I was able to measure it.  As I drove to the hawk watch my car’s outdoor thermometer registered 43o in the Laurel Highland valleys and 57o on top of the mountain.  Normally the hawk watch site is far colder than anywhere else in western PA.

The weather was topsy-turvy.  Warm air aloft trapped cold air below and with it pollutants that made the air smell bad in the cold zones.

Bad air was not limited to cities and industrial zones.  On my way to the Allegheny Front I saw quite a few outdoor wood boilers creating thick white smoke that blanketed rural areas.  These relatively new devices burn wood in backyard sheds to heat water for radiators in homes.  Because outdoor wood boilers are small scale polluters they weren’t on the bad air radar at first, but their smoke is much worse than typical burning because the fire smolders when indoor heat demand is low.  I saw valleys where wood smoke enveloped nearby homes and neighbors.

At the hawk watch the air was nice and warm.

So when there’s an inversion, go to the mountain.

(photo by Kate St. John)

The Trees With Leaves Are…

Schenley Park, Trees, Winter Weeds & Trees

13 November 2012

At this point in November most of the trees in western Pennsylvania have lost their leaves.  There are exceptions and you’re likely to find them in parks and residential areas.

Yesterday morning I took this picture at the big bend on Greenfield Road in Schenley Park.  If you didn’t know it was a recent photo you’d think it was taken in early October at the peak of autumn color.

These are Norway maples whose native range in Europe extends further north than Pittsburgh.  Our short November days are the same length as those they experience in October back home.  For instance, the sun will be up for exactly 10 hours today in western Pennsylvania.  That’s the day length in mid October in Scandinavia.

Right now our native trees are bare or retain just a few leaves at the top (tulip trees) or brittle brown leaves overall (oaks and beeches).

The non-natives plants are out of synch and late November is the one time of year when you can easily see them across the landscape.

Make an effort to identify the trees and plants with green or colorful leaves and you’ll find that they’re probably imported.

(photo by Kate St. John)

Follow Peregrines With The Bird Guys

Books & Events, Peregrines

The Bird Guys With Vern and Bob (image from zap2it.com)

Birders and peregrine fans!  If you’re an early-to-bed person, get your beauty rest this Thursday November 15 and plan to stay up for the 10:30pm broadcast of The Bird Guys With Vern and Bob on WQED.

It’s a fun half-hour program that follows Vern Laux and Bob Shriber as they visit Monhegan Island, Nantucket Island and the Florida Keys during fall migration.  They’re on the trail of peregrine falcons but as dedicated birders they show us lots of other birds along the way.

Vern Laux is a fun guy and excellent birder who writes a birding column for the Cape Cod Times and hosts a radio program on the Cape and Islands’ public radio stations. When a rare bird is found on Nantucket, Vern’s the one who finds it.  (Remember the first North American record of a red-footed falcon in August 2004?  That was Vern.)

Bob Shriber is a birder and television producer from New York who’s worked with Vern on several videos. When you don’t see Bob on camera it’s because he’s filming the show.

The Bird Guys have a great time as they follow birds down the East Coast.  Always hoping to see peregrines they hit “pay dirt” at Marathon Key where they see at least five peregrines in view at all times.  And that’s not all they see.  Don’t miss Vern’s encounter with a skunk!

Vern and Bob make birding fun.  Watch The Bird Guys on Thursday, November 15 at 10:30pm on WQED.

(image linked from Zap2it.com. Click on the image to see the original)

 

p.s.  Speaking of peregrine migration, the arctic peregrines have already made it to South America.  See Island Girl’s trajectory at the Southern Cross Peregrine Project.