Archive for the 'Musings & News' Category

Mar 12 2013

The Importance Of Fire

Published by under Musings & News,Travel

A helicopter drops water on a wildfire in California, Oct 2007 (photo by FEMA via Wikimedia Commons)

Early this month it was scary to read Chuck Tague’s account of a brush fire that came within two miles of his Ormond Beach home.

While the fired burned in Florida I was in another fire-prone place, San Diego, listening to a speech by Dr. John Fitzpatrick of the Cornell Lab of Ornithology in which he touched on how important fire is for scrub habitats and for the survival of the Florida scrub-jay in particular.

To most of us wildfire is rare but it’s a natural cycle in scrub communities where plants, animals, and birds rely on its regular occurrence.   “Regular” is important.  If fire happens too often or too infrequently that’s bad too.

It has taken a while to learn this.  Dr. Fitzpatrick described how they studied fire and birds at Archbold Station in Highlands County, Florida.  For two decades Archbold suppressed fires and watched the scrub-jay population surge then dangerously decline.  After 20 years scientists burned small tracts and watched the scrub-jays surge again.  They learned that the Florida scrub-jay’s optimal habitat is at 5-15 years after a fire.  At 15 years the scrub gets too tall, the jay’s predators increase and the birds decline.

Fire is necessary.  The trick in populated areas is to manage it so it happens only when and where it’s needed.

In San Diego the local government conducts brush management programs to protect homes and businesses.  According to San Diego Audubon, these programs sometimes make matters worse.  If workers clear away native chaparral, it not only destroys endangered bird habitat but results in fire-prone grassy weeds that burn more easily. Proper management of native habitat actually lowers the risk of explosive fire.

So though we fear it, fire is important.  Without it we wouldn’t have Florida scrub-jays, California gnatcatchers and coastal cactus wrens, to name a few.

(photo of a helicopter dropping water on a California wildfire, by FEMA via Wikimedia Commons. Click on the image to see the original.)

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Mar 05 2013

The Triple Fence

Published by under Musings & News,Travel

Border Fence at Canon de los Sauces, 2012 (photo by Jill Marie Holslin)

Travel is very educational.  Not only are there different birds in San Diego but the threats those birds face are different from what I’m used to in Pittsburgh.  One issue particularly grabbed my attention because we never have to deal with it at home.

Where I come from it’s hard to imagine the wall that defines the southern edge of San Diego County.  Like the Berlin Wall it’s patrolled by armed guards, edged by cleared land for easy enforcement, and in places triple-fenced.

The border has been patrolled for a long time but the Real ID Act of 2005 mandated the border wall and exempted its construction from every environmental law including the Endangered Species Act, the Migratory Bird Treaty Act, the Clean Water Act, the Clean Air Act, and the National Environmental Policy Act.  Exemptions like this bring to mind mountaintop removal in West Virginia.

During design of the Triple Fence, San Diego Audubon and other groups tried to prevent the worst environmental damage but it was impossible to stop the juggernaut.  Now that the wall is up, they’re working with California State Parks and the Tijuana National Estuarine Research Reserve to monitor the wall’s effect on sedimentation, erosion, and invasive plants.

There are lots of problems to monitor.  Here are just two examples.

The fence through Yogurt Canyon, shown above, disrupts the natural drainage into the Tijuana Estuary to the north.  This affects everything that depends on the water, including birds.

At Border Field State Park, shown below, the wall’s construction leveled Litchy Mesa and filled Smugglers Gulch.  There used to be a single fence.  Now there’s a massive valley-fill and all the issues that come with it.
Smugglers Gulch before and during the Triple Fence project  (photos by Jill Marie Holslin)

Ironically, the wall has an unintended consequence.  In the old days workers used to migrate back and forth like the birds — north for planting and harvesting, south to their homes in the winter.

In his 2001 book, Crossing Over, Rubén Martínez described how the patrols even then were ending the return migration.  It’s now so dangerous at the wall that those who get here can rarely leave.

I’m sure that’s not the result the wall’s proponents had in mind.

Read more about the border fence and how it affects the land and people of Tijuana and San Diego in Jill Marie Holslin’s blog, At The Edges.

(photos used by permission of Jill Marie Holslin from her blog, At the Edges. Click on each image for more information.)

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Feb 28 2013

Romancing The Wind

Published by under Musings & News,Travel

My love of birds has me fascinated with almost anything that flies.  Perhaps this is true for you too.

Last month my sister-in-law sent me a link to this 2004 video called Romancing The Wind.  Produced by Robert Holbrook, it shows professional kite flyer Ray Bethell flying three kites simultaneously in an aerial ballet.  Music from Leo Delibes’ The Flower Duet complements the kites.

Ray Bethell is an amazing man.  Over 80 years old, he’s a Multiple Kite World Champion from Vancouver, Canada who holds world records in endurance and number of simultaneous kites flown.  Here you see him flying three kites at Vanier Park, holding one in each hand with a third tied to his belt.  He’s used this same technique to fly 39 kites at the same time!  Read more on his website here.

Like the falcons, Ray Bethell’s kites court in the wind.

 

p.s. The kite model Ray is using has a falcon name:  Kestrel.

(video of Ray Bethell by Robert Holbrook on Vimeo)

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Feb 27 2013

A Victory For Birds In Canada

Published by under Musings & News

Yonge Corporate Centre (photo from Yonge Corporate Centre)

If you’ve read this blog for any length of time you’ve been here with me when I’ve mourned the loss of yet another juvenile peregrine who died by hitting a window.  We lose at least one of Pittsburgh’s young peregrines this way every year.  Windows kill but now there’s a ruling in Canada that gives me hope this will change, even in the U.S.

This month Judge Melvyn Green of the Ontario Court of Justice ruled that two laws that protect birds in Canada, EPA and SARA, “are properly interpreted to prohibit the emission (intentional or unintentional) of reflected light where that reflection causes the death or injury of birds.”

In other words, massive window kills count just as much as if you’d shot the birds.  Your windows are breaking the law.

The buildings that prompted the ruling are Yonge Corporate Centre, pictured above, one of many corporate centers in Toronto where thousands of birds are injured or killed each year.  To their credit Yonge Corporate Centre had already begun to mitigate the problem with window film, due in part to a lawsuit by Ecojustice Canada and Ontario Nature against another deadly corporate center, Consilium Place.  Click here for a photo of Consilium Place and information on the lawsuit.

“The law is now clear that owners and managers of buildings with reflective windows that kill or injure birds must take action. This is a major success, even if it’s not a complete victory,”said Ecojustice lawyer Albert Koehl.

So a big thank you goes out to Ecojustice Canada, Ontario Nature and the Fatal Light Awareness Program (FLAP) for this victory!  I hope it ripples southward and prompts a change in the U.S. too.

 

Read more about the ruling in the American Bird Conservancy’s press release, source of the quotes above.

(photo of Yonge Corporate Center from the media page of Yonge Corporate Center website. Click on the image to see the original.)

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Feb 04 2013

Which Kills More Birds?

Published by under Musings & News

Windmill and Cat named Lilith (photos from Wikimedia Commons)

In case you missed it last week, the numbers have changed.

The Smithsonian Conservation Biology Institute and U.S. Fish and Wildlife Service developed a mathematical model, used data from 21 of the most rigorous cat-wildlife studies, and ran the numbers on cats.

The results were quite surprising.  2.4 billion birds are killed by cats every year in the U.S.  That’s two to four times the old statistics.

Compare this new data to other human-induced causes of bird mortality(*) and cats are now on top.

  • Cats: 2.4 billion
  • Windows: 1.0 billion
  • Power lines: 0.174 billion
  • Communication towers: 0.051 billion
  • Windmills: 0.0004 billion

So you can stop worrying about windmills.

If you want to save birds’ lives, keep your cat indoors.  I do.

 

Read more about this study including information on feral and pet cats in the New York Times.

(photo of windmill and a former stray cat named Lilith, both from Wikimedia Commons.  Click on the imbedded links to see the original photos)

 

(*) p.s. I’m not sure where habitat loss fits in now, but it has always been the leading cause of human-induced bird mortality.

p.p.s. I love both birds and cats.  Here are two posts about my beautiful indoor cat, Emmalina:  Mouse in the House and Animal, Vegetable.

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Jan 31 2013

Walking Down Vortex Street

I know almost nothing about fluid dynamics but my article about wingtip vortices two weeks ago piqued my interest in the subject.

Last weekend I learned about this amazing phenomenon, the von Kármán vortex street, animated above by Cesareo de La Rosa Siqueira.

Von Kármán vortex streets occur when a fluid flows past a stationary object and generates a long line of vortices that swirl in opposite directions.  The phenomenon was named for Theodore von Kármán, the man who described it, and is probably called a street because it looks like one.

We usually don’t see von Kármán vortex streets in the wind, but it’s important that engineers plan for them.  If a tall structure is uniformly straight the vortices can make it fall down.  Click here to read about a famous mistake.

On a small scale, von Kármán vortex streets make telephone wires sing in the wind.  On a large scale they’re visible from outer space when clouds blow past a tall island.

Here’s a picture taken from the space shuttle that shows cloud cover blowing past Rishiri Island, Japan.  When the wind encounters Mt. Rishiri the clouds form a von Kármán vortex street on the downwind side.

Pretty cool, huh?

There are more than twenty islands that reliably generate von Kármán vortex streets.  Click here to see more pictures from NASA.

(Vortex animation by Cesareo de La Rosa Siqueira via Wikimedia Commons.  Space shuttle photo from NASA via Wikimedia Commons. Click on the images to see the originals)

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Jan 01 2013

2012: The Year In Review

Nature was busy and interesting in 2012.  The weather was hot, stormy, dry, and sometimes wet. This brought exciting developments in the natural world.

Here’s a month-to-month roundup of my favorite high points with each photo linked to an article about the event.  Some link to my blog, others link to information on the web that I didn’t point out at the time.

 

  • January: Snowy owls were abundant in the northern U.S. into March. (photo by Shawn Collins)
  • February: The warm winter prompted a massive Canada goose migration on February 27 in eastern Pennsylvania, New York State and Ontario. (photo by Chuck Tague)
  • March:  Pittsburgh’s temperatures averaged 11.9 degrees above normal with some days 20 degrees above normal. Spring wildflowers bloomed 4-6 weeks early. (photo by Kate St. John)
  • April: There was a mass migration of Red Admiral butterflies in mid-April. (photo from Wikimedia Commons)
  • May: Birds who wintered in the U.S. migrated early but the warblers were right on time. (photo by Bobby Greene)
  • June: A new peregrine family was confirmed at Tarentum, PA when their nestlings appeared on the bridge. (photo by Steve Gosser)
  • July: Drought! (photo from NOAA NWS)
  • August: Every year I count nighthawks passing my home during their August migration.  Every year there are fewer.  Sadly, 2012 was no exception. (photo from Wikimedia Commons)
  • September: Arctic sea ice at its lowest extent ever. (photo from NOAA)
  • October: Hurricane Sandy brings unusual birds to western Pennsylvania. (photo by Jeff McDonald)

  • November: A surprising number of western hummingbirds visit Pennsylvania: rufous, calliope, Allen’s (photo by Scott Kinsey)
  • December: Evening grosbeaks visit Pennsylvania after decades of absence (photo by Marcy Cunkelman)

 

Happy New Year!

 

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Dec 17 2012

Singing Sand

Published by under Musings & News,Travel

I rarely spend time near sand dunes so I was amazed to learn that sand can sing.  In fact there are 35 places around the world where the dunes sing a low frequency hum in the bottom half of a cello’s range.

The droning happens naturally when the wind causes a sand avalanche.  People can force the song by pushing sand downhill.  The songs are well known but people have always wondered how and why they happen.

Some of the “how” is already known.

Singing dunes are crescent-shaped barchans with their backs to the wind and their horns pointing downwind.  The slipface is inside the crescent (downwind) with its surface at the angle of repose and a stationary layer beneath.

Experiments have shown the importance of the grains themselves.  If they’re spherical,  0.1 to 0.5 mm in diameter, and contain silica, they will sing in the lab when they slide down an incline.

This year physicists from Paris Diderot University discovered that grain size determines the tune.  They studied two dunes:  one in Morocco, one in Oman.   The Moroccan dune has grains 150-170 microns and emits a 105 hz sound (for musicians that’s near G-sharp two octaves below middle C).    The Omani dune has a variable grain size from 150 to 310 microns and its sound varies, too — from 90-150 hz (F-sharp to D).

Researchers took the Omani sand back to the lab and sifted it down to a nearly uniform size — 200 to 250 microns — and sent it down an incline.  Voilà.  The sand made a sound of 90 hz, close to the song of the Moroccan dune.  (Click here for more information about the study.)

What are the songs like?  In this video, filmed in Morocco, a man shows how he learned to make the sand sing.  Turn up your speakers and you’ll be able to hear a variety of sounds as he puts the sand through its paces.  The video is in French with subtitles, some of which are surprisingly translated as in the first sentence that says “Beware” when it means the less dangerous-sounding “Be aware.”

Thanks to science we’ve learned how the sand sings, but we still don’t know why.

(video from YouTube)

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Nov 26 2012

The Triple Divide

Published by under Musings & News

There’s a unique place in north central Pennsylvania at the top of three major watersheds. It’s called The Triple Divide.

When a raindrop falls there it can split three ways:

  1. In one direction, it flows west to the Allegheny River, down the Mississippi watershed and into the Gulf of Mexico.
  2. Or it flows north to the Genesee River, Lake Ontario, the Saint Lawrence watershed and into the north Atlantic.
  3. Or it flows southeast to Pine Creek, the Susquehanna River, Chesapeake Bay and the Atlantic Ocean.

The spot is in Genesee Twp, Potter County, Pennsylvania and is marked with the sign pictured above.

The location itself is unremarkable.  It’s not a big mountain, just a hill on the Allegheny Plateau near the New York state line.  It’s not even the highest point in Pennsylvania, but it spawns three major North American rivers:  the Mississippi, the St. Lawrence and the Susquehanna.

According to Dr. Robert N. Andersen at University of Wisconsin Eau Claire, “Triple divide points are ubiquitous in North America. Wherever there is a confluence of two streams there is a Triple Divide Point uniquely associated with the confluence. ”  Then he uses Pittsburgh’s confluence of the Allegheny and Monongahela Rivers to describe how to find a triple divide near us.

Beginning at the Point in Pittsburgh, trace the border of the Allegheny and Monongahela watersheds, moving upstream. Eventually you reach the place where the border ends.  At that point in Somerset County, east of Berlin, PA, is a triple divide that drains the Mississippi (via the Conemaugh and Youghiogeny), the North Branch of the Potomac, and the Susquehanna River (via the Juniata).

In the western U.S. there are triple divides that drain to both the Atlantic and Pacific.  And somewhere in Canada there’s an oceanic triple divide where a raindrop can split and flow to the Arctic, the Atlantic and the Pacific Oceans.

Follow a raindrop uphill and you’ll eventually find a triple divide.

(photo by Nicholas A. Tonelli on Wikimedia Commons. Click on the image to see the original and explore the location on Google Maps)

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Nov 20 2012

New Series

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.

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