Yearly Archives: 2012

Waves and Windows in the Sky

Weather & Sky
Wave window clouds over Bald Eagle Valley, PA (photo from Wikimedia Commons)

5 September 2012

When I wrote about lenticular clouds last week Tom Stepleton of the Pittsburgh Soaring Club commented on how useful they are for glider pilots — a sure sign of an updraft that will take a glider high and far.

He also mentioned another orographic cloud that’s more common above Pennsylvania’s mountains: the wave.

This photo, taken by a glider pilot, shows two waves with a window over Bald Eagle Valley in north central Pennsylvania.  The clouds are formed by the same wind pattern that creates lenticular clouds but instead of creating a lozenge-shape the long ridge produces a wave.

The best conditions often occur in the fall when a cold front brings northwest winds that hit the mountains at a 90 degree angle.

Pictured here the wind hits the Allegheny Front (on the left) and rises up to create the first wave.  The air drops and creates a window over the valley, then rises again to create the second wave.

The pilot was flying north but I’m sure he saw hawks heading south using the same updraft to make their journey easy. (This photo was taken in autumn; the trees are changing color.)

It would have been a good day to be at the Allegheny Front Hawk Watch … as long as that cloud stayed well above the ground.

(photo by Dhaluza on Wikimedia Commons.  Click on the photo to see the original and read more about it.)

Flightless

Travel, Water and Shore
Common eider, female (photo by Stuart Burns via Wikimedia Commons)

4 September 2012

The other day at Acadia National Park I watched a female common eider (Somateria mollissima) climb up on a boulder and eat the barnacles.  At one point she opened her wings and I saw that 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 weren’t long enough to carry her.  Why?  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 eiders because swimming is their most important skill.  It’s how they get their food (marine crustaceans) and how they avoid predators.

Like eiders Canada geese go through a flightless period, too, but I never noticed it.  They hide it well.

It’s taken me a long time to realize that I’ve never seen a common eider fly because I only visit their home when they’re flightless.

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

The Calico Bird

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)

Chatterboxes

Bird Behavior, Songbirds

Red-breasted nuthatches are really common here in Maine.

Even when I don’t see them I can hear their “tin horn” voices saying “yank, yank, yank, yank” as they walk the tops of pines and spruces looking for insects.

Sometimes in the morning a group of them meets up and the “yank yank yank” gives way to long, melodic conversations and murmurs.  It sounds as if they’re telling stories over coffee.  I wait for the punchline.

I had no idea they were such chatterboxes.

(photo by Chuck Tague)

To The Lighthouse

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)

Triumph of Agility

Bird Behavior, Birds of Prey

Bald eagles are majestic but opportunistic.  Sometimes they use their power to steal from others.

I once saw an osprey plunge feet first into a bay, grasp a fish in his talons, and flap like crazy to pull up.  As soon as he gained some altitude he shook off the water, just like a dog, and arranged the fish head first for aerodynamic flight.  Then he was on his way…

… or so he thought.  A bald eagle was watching and decided to steal the fish.

Eagles are fast, powerful fliers on the straight-away and this one knew he had the advantage.  He gained on the osprey so quickly I was certain he’d hit him and take the fish.

But the osprey had experience with eagles.  He turned and ducked, backtracked and swerved.  Sometimes he flew up, sometimes down.  The eagle kept up with him but was slower to make the turns.  There were moments when the eagle was breathing down his neck but the osprey always escaped.

The osprey knew something I did not.  The eagle was getting tired.

Suddenly, to my surprise, the eagle turned and rapidly flew away from the osprey.  Through binoculars I could see the eagle’s beak was open.  He was panting!

The osprey’s agility won the day.

(photo of an osprey by Steve Gosser)

If Only They Were All This Easy

Water and Shore
Black-bellied plover (photo by Chuck Tague)

At this time of year I’m “shorebird challenged.”   Some days I can barely identify them.

A couple of years ago I learned to look at legs and beaks … leg color, beak color, leg length, beak length, beak shape … but every year I forget what I’ve learned and have to start over.

None of their identities come easy.  Except this one.

In breeding plumage a black-bellied plover has a black belly, otherwise his belly is white. However, when he opens his wings his armpits give him away. He never loses his black axillaries.

The trick is to get him to open his wings.

I wish all shorebirds were this easy.

(photo by Chuck Tague)

The Mountain is Wearing a Hat

Weather & Sky
Lenticular cloud over Mt. Hood (photo by Yapin Wu via Wikimedia Commons)

29 August 2012

Smooth clouds like this are my favorite because they look like lozenges or flying saucers.  Sometimes they’re in compound shapes like this “hat” on Mt. Hood.

Lenticular clouds are most common near mountains because the wind hits the mountain, creates an updraft and becomes a large standing wave.  When moisture condenses at the top of the wave, a stationary lenticular cloud forms there.  The long lozenge shapes are usually perpendicular to the wind.  They sure don’t look that way!

When the wind hits the mountain the waves look like this. 

Lee waves and windows (image from Wikimedia Commons)

Notice the stationary clouds at crests A and B. The wind follows the shape of the mountain — twice! The updraft on the windward side of the mountain is provides uplift for glider pilots but the downdrafts can be deadly. There’s a lot of turbulence in those standing waves. Powered aircraft avoid them.

Pittsburgh rarely has lenticular clouds, though a front creates one occasionally.

For really cool clouds you have to visit the mountains.

(photo of cloud by Yapin Wu via Wikimedia Commons. Diagram of wave lift by Dake on Wikimedia Commons.  Click the captions to see the originals.)

Save The Date, Flip A Rock

Books & Events

It’s time to get ready. Sunday, September 9 is International Rock Flipping Day.

Begun in 2007 by Dave Bonta and Bev Wigney, International Rock Flipping Day (IRFD) is a blog carnival celebrated every year by flipping a rock, blogging what you find, and sending your blog link to Wanderin’ Weeta.

How international is it?  In 2010 the best find was a rock monitor (lizard!) in South Africa.

This year IRFD is expanded.  If you don’t have a blog you can still participate by posting your photos in the Rock Flipping Day Flickr group.

Ready to go?  Here are instructions from Wanderin’ Weeta:

  • On or about September 9th, find your rock and flip it over. Note the safety precautions below!
  • Record what you find. Any and all forms of documentation are welcome: still photos, video, sketches, prose, or poetry.
  • Important: Replace the rock as you found it; it’s someone’s home.
  • Post on your blog, or load your photos to the Flickr group.
  • Send the link to Wanderin’ Weeta or add a comment to her IRFD post.
  • She’s collecting all the links and will e-mail you the participants list so you can post it on your blog as well. If you’re on Twitter, Tweet it, too; the hashtag is #rockflip.
  • Click here to get the handy logo on Wanderin’ Weeta’s website.

And now, a word about safety from Dave Bonta:

One thing I forgot to do in the initial post is to caution people about flipping rocks in poisonous snake or scorpion habitat. In that case, I’d suggest wearing gloves and/or using a pry bar — or simply finding somewhere else to do your flipping. Please do not disturb any known rattlesnake shelters if you don’t plan on replacing the rocks exactly as you found them. Timber rattlesnakes, like many other adult herps, are very site-loyal, and can die if their homes are destroyed. Also, don’t play with spiders. If you disturb an adjacent hornet nest (hey, it’s possible), run like hell. But be sure to have someone standing by to get it all on film!

And a word about respect and consideration:

The animals we find under rocks are at home; they rest there, sleep there, raise their families there. Then we come along and take off the roof, so please remember to replace it carefully. Try not to squish the residents; move them aside if they’re big enough; they’ll run back as soon as their rock is back in place.

So pick your favorite rock on September 9 and flip away.  I wonder what we’ll find!

 

(photo of a smooth granite rock in Northeast Harbor, Maine by Kate St. John)

p.s. Stay tuned for my results on Sept 9.  Will I flip that rock in the photo?

Beachy Bird

Beyond Bounds, Migration

According to Birds of North America Online this slender, inconspicuous bird begins its southward migration next month.

American pipits breed in some of the harshest habitat of any songbird.  They prefer open tundra and mountaintops above treeline where bad weather is the greatest threat to their nesting success.  In a bad year, their nests suffer 80% mortality when deep springtime snow covers their eggs and young.

In the fall they avoid the coming snow, flying south to beaches and open mudflats. I’ve seen them at the edge of Shenango Lake and on the treeless mountaintops of Acadia National Park.

I even saw several lone pipits on the beach at Cape Cod in early August.

I don’t know why those August pipits left the tundra for the beach but it certainly wasn’t because of snow this summer!

(photo by Alan Vernon via Wikimedia Commons. Click on the photo to see the original)