Archive for the 'Travel' Category

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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Mar 04 2013

Thrashing It Out

Published by under Songbirds,Travel

California thrasher (photo by Alan Vernon from Wikimedia Commons)

We’re starved for thrashers in Pittsburgh right now.  Of the eight species in North America only one, the brown thrasher, occurs in the eastern U.S. and he’s away on migration.  All the rest are western or southwestern birds, several of which occur in California.

This one has “California” in his name.  He doesn’t migrate — in fact he hardly moves away from his birthplace — so if you want to see him you have to be in California or northern Mexico.

The California thrasher loves dense desert chapparel but is sometimes found in scrubby or suburban habitat where he encounters a bird whose habits are quite similar.

Northern mockingbirds eat the same food and forage in the same way as California thrashers.  Both are highly territorial so when a mockingbird moves into a thrasher’s territory constant warfare ensues.

Imagine the two contestants hopping and lunging.

Hey, Mr. Mockingbird, watch out for that beak!

Fortunately for northern mockingbirds, few of them like dense chaparral so these species are usually in separate places.

Good for the thrasher too.  What a waste of energy to be constantly thrashing it out!

 

(photo by Alan Vernon from Wikimedia Commons. Click on the image to see its original)

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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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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)

7 responses so far

Sep 14 2012

Banner Waving

Published by under Travel,Weather & Sky

Two weeks ago the mountain was wearing a hat.  Today it’s waving a flag.

Banner clouds are stationary, orographic clouds that only form in high wind on the leeward side of an isolated, steep mountain.  The Matterhorn, pictured above, is famous for them.

Banner clouds are so picky that we’ll never see them in western Pennsylvania simply because we have no isolated steep mountains.

… except …

Under the right moisture conditions a banner cloud can form above or just behind an airplane’s wings. Click here for an example.

Airplanes form banner clouds because there’s lower air pressure on top of their wings (to generate lift).  The lower pressure results in lower temperature which results in condensation.  Hence a cloud.

My favorite banners are the wing tip clouds that look like streamers.

And for a really weird effect, check out this cloud around a fighter jet on the verge of breaking the sound barrier.  The shape is so perfect it’s hard to call it a banner.

(photo by Zacharie Grossen on Wikimedia Commons. Click on the photo to see the original)

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Sep 08 2012

Mirror Gannets

Published by under Travel,Water and Shore

Northern gannets were the most numerous sea bird on my whale watch trip this year.  Some were adults, some were juveniles, but few had the peachy colored head feathers of these breeding adults.

This pair was a lucky shot.  When the photographer took their picture they were mirror images of each other.

Posed perfectly. Frozen in time.

(photo by Des Colhoun via Wikimedia Commons.  Click on the photo to see the original, including a link to its geographic location.)

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Sep 06 2012

Antarctic Visitor

True confessions.  When I’m in Maine I usually go on a whale watching trip but my real goal isn’t whales, it’s pelagic birds.

I’m not the only birder on the whale watch boat.  There’s usually a dozen of us keeping our eyes peeled for gannets, shearwaters, jaegers and storm petrels.

Storm petrels are my favorites because they’re so dainty.  Only the size of starlings, they appear to walk on water as they search for food.

The most common type in the Gulf of Maine in early September is Wilson’s storm petrel, pictured above.  When I learned where they came from I was amazed.

Wilson’s breed in colonies on the coast of Antarctica.  Like most storm petrels they nest out of sight in crevices and burrows and only visit their nests under cover of darkness.  That’s how they hide their eggs and young from raiding gulls and skuas.

When not breeding they live on the open ocean and never come to the land, but they’re easy to see on a pelagic trip because they’re willing to approach boats.

So while it’s winter on the southern ocean I get to see this Antarctic visitor off the coast of Maine. Soon they’ll journey back.

(photo by Patrick Coin via Wikimedia Commons.  Click on the photo to see the original)

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Sep 04 2012

Flightless

Published by under Travel,Water and Shore

The other day at Acadia I watched a female common eider climb up on a boulder and eat the barnacles.  At one point she opened her wings and I saw they were surprisingly short.

Since eiders are the largest duck in the northern hemisphere they need substantial wings to fly, but this bird’s wings didn’t look long enough to carry her.  Was she crippled?  No, she was molting.

Like many ducks and geese, common eiders completely molt their tail and wing feathers in late summer after the breeding season.  This means they can’t fly for 3-4 weeks.

This isn’t a terrible hardship for an eider because swimming is their most important skill.  It’s how they get their food (marine crustaceans) and how they avoid predators.

Eiders aren’t the only ones who go through a flightless period every year.  Canada geese do, too, but I’ve never noticed it.  They hide it well.

It’s taken me a long time to realize I’ve rarely seen an eider fly.  I only visit their habitat when they’re flightless.

(photo by Stuart Burns via Wikimedia Commons.  Click on the photo to see the original)

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Sep 03 2012

The Calico Bird

Published by under Travel,Water and Shore

When ruddy turnstones arrive on the U.S. coast in August, they’re still decked out in their calico colors: black, white and rusty red.

Though all of them are born in the Arctic, ruddy turnstones spend only three months up there.  The adults arrive on the breeding grounds in late May or early June and lay eggs by mid-June.  The eggs hatch by mid July. The young fledge by early August.  As soon as the young are independent their mothers, then their fathers, leave for the south.  By mid-August most of the adults have left.  The young follow soon.

This schedule means that the first ruddy turnstones we see in August are probably adult females.  I saw some early turnstones, probably female, at Cape Cod on August 2nd.  Chuck Tague saw his first in Florida around August 22.

Perhaps they’re in a hurry to go south. I haven’t seen any on the coast of Maine this week.

(photo by Steve Gosser)

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Sep 01 2012

To The Lighthouse

Published by under Travel

When I’m at Acadia National Park, as I am right now, I make sure to visit to the southwestern edge of Mount Desert Island where migrating song and shorebirds stop before launching across Blue Hill Bay.  This lighthouse marks the southern tip.

The Bass Harbor Head Light has warned sailors of the rocky entrance to Bass Harbor since 1858.  It was automated in 1974 so there’s no access inside, just a pretty walk down to the shore where the view of the lighthouse dominates the sky.

But don’t take that walk in the fog. The path is rocky and steep.

You need fair weather to go to the lighthouse.

(photo from NOAA via Wikimedia Commons. Click on the photo to see the original)

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