Outside My Window

If you love huge bird events you’re going to love what Sharon Leadbitter saw last Saturday evening.

Sharon went to the Strip District and filmed the crows coming into the roost.

Thousands upon thousands gathered in the trees.  As night approached they began to do The Wave, just like a crowd in a football stadium.

And they cheered as they rose from their seats.  (Turn up your speakers!)

Check out time code 0:59 to 1:15.

Woo hoo!

(video by Sharon Leadbitter)

p.s. Sharon adds, “If anyone wants to join me sometime, the crows start showing up at about 4:55pm and keep coming until around 6:30 or so.”  She posted additional pictures at her Facebook media site here.

Why do swans, geese, and ducks fly in V formation?

Because it makes their journey easier.

Everything that flies experiences turbulence that slows it down.  Some of the turbulence is created by the act of flying.  For instance, during lift cones of swirling air called vortices roll off the wingtips and induce drag.

Here’s a dramatic NASA photo of a wingtip vortex, enhanced by red smoke.

The right and left wing vortices swirl in opposite directions — the left spins clockwise, the right counter-clockwise — resulting in two trailing swirls behind the airplane or bird.  Click here and here for videos.

The induced drag is especially hard on large or heavy birds (swans and geese) and birds with small wings relative to their size (ducks) so these birds line up in Vs to reduce the turbulence.

Here’s how it works.

In the photo below, four tundra swans are flying in the direction of the blue arrow.  Behind the leader, the blue lines show that each bird has its right wingtip in line with the left wingtip of the bird ahead of it.

Now I’ll draw the vortices and their spinning directions using blue for the left wing, red for the right wing.  Blue/left spins clockwise.  Red/right spins counter-clockwise.

When the blue vortex meets the red vortex at the wingtip, they cancel each other out.   By lining up in this fashion, each bird has one wing that experiences less turbulence.  That makes it easier to fly.

The lead bird is out there alone, though.  He’s the only one who gets no assistance so he tires before the rest of the flock.  The flock solves this by changing leaders when the first one needs to rest.  The lead bird drops back into the V and another bird takes his place.

Long, long ago birds solved the problem of wingtip turbulence.  When we invented airplanes we found out what it was all about.

(Credits:
Photo of tundra swans in blue sky by Chuck Tague.  Line of tundra swans by Marcy Cunkelman.  Red vortex photo by NASA via Wikimedia Commons; click on the image to see the original.
Today’s Tenth Page is inspired by a diagram on page 123 of Ornithology by Frank B. Gill.)

I love this photo that Steve Gosser posted on Facebook last week. 

Textbooks describe ring-billed gulls as opportunistic feeders, “exploiting chances offered by immediate circumstances without reference to moral principle.”*

No respecters of age or experience, the top gull is a “teenager” (a second winter immature), the bottom one an adult. 

There are loads of fish in Lake Erie but one of them decided to steal a fish from his neighbor rather than catching one on his own.

Fish fight!

(photo by Steve Gosser)

(*) per Google’s dictionary

In Physics class I learned Newton’s Third Law of motion:  For every action there is an equal and opposite reaction.

The woodpecker flies, the feeder swings.  You can see his thrust in the feeder’s tilt.

(photo by Marcy Cunkelman)

Peacocks are very noisy during the breeding season, especially when they call with repeated penetrating screams.

Not only do they scream but the male makes a unique call just before he mates with a female.  As he dashes toward her he lets out a bell-like whoop.

This call intrigued Duke University biologist Jessica Yorzinski.  Why do male peacocks do this?  The sound gives away their location and could tell predators, “Hey! There are two very distracted peacocks over here.”

She studied the whoop by playing back recorded bird sounds, including crow caws and the whoop, to wild peacocks in India.  The peahens ignored the other sounds but when they heard the whoop they actually walked toward the audio speakers.  Yorzinski also tried the playback with captive peafowl at Duke.  The result was the same.  The ladies approached the sound as if they were thinking, “There’s a really hot guy over there.  I think I’ll go see.”

In the video above a lone male makes two kinds of calls.  He repeats the scream interspersed with a sound like the “whoop”  at time codes 0:22, 0:39, 0:56, 1:08, and 1:44.   Yes, I think he’s faking it.  He seems to be pretending he’s mating with a peahen and hoping the other peahens come to see.

When he mates with a female in this video he makes a softer whoop, the real one.

Click here for more information on this study in Science Daily.

(video from peacocklover27 on You Tube)

When bird habitat disappears some people say, “Birds can fly.  They should just move and they’ll be fine.”

A new study published last month in Ecology Letters shows why that idea doesn’t work.

Oxford University scientists, lead by Dr. Alex Pigot, studied the ovenbird(*) (Furnariidae) family in South America.  They found that closely related species who evolved similar feeding strategies do not live in the same area.  This isn’t just a local exclusion, it’s regional.

Feeding strategies are often characterized by the shape of the bird’s beak and Furnariidae have some amazing ones!  This bird, the black-billed scythebill, pulls insects out of bark, bamboo and bromeliads.  The large range of his close relative, the red-billed scythebill, barely overlaps.  Each species has its niche.

What happens to displaced birds when habitat is lost?   Obviously, the homeless birds find a new location but other species are already there and successfully exploiting the niche the new birds need.  Out-competed by locals, the new arrivals may not survive.

Thus the study suggests that the effects of climate change will not be a simple shifting of bird populations but new layers of competition in a changing world.

Read more about this study of beaks and ranges here in Science Daily.

(photo of a black-billed scythebill in Brazil from Wikimedia Commons.  Click on the image to see the original)

(*) Furnariidae are not related to our ovenbird warbler though both build nests that look like little Dutch ovens.

The lady peahen in this video looks brown and boring but her presence prompts two peacocks to fan their tails.

The adult male struts and quivers his beautiful upper tail coverts.

The young male raises his pathetically small feathers and tries to do the same.

Can he win?  Watch and see.

(video by peacocklover27 on YouTube)

Here’s an Asian pheasant, a Temminck’s tragopan, that normally looks vermillion, black, white and brown.

When he’s in an amorous mood he shakes his head to begin his courtship display.  Two long blue horns pop up from his head and the small blue patch under his chin drops down to reveal an intricate iridescent blue lappet.

He opens his wings, puffs his body, and continues to shake his head to perfect his display.

And just in case his lady doesn’t notice, he clacks his beak.

Look at me!

Click here to see another Temminck’s tragopan with an even bigger, better lappet.  In a contest between the two, I bet the ladies will pick the guy with the bigger bib.

(video from YouTube)

p.s. The name “tragopan” has an interesting origin:  Trago is the Greek work for goat, Pan is the Greek god of the wild whose shape is half man, half goat.

Peregrine fans, does this photo remind you of someone?

This scene is from Baringo Cliffs, Kenya where a lanner falcon attacked a Verreaux’s eagle and forced it to flip upside down to defend itself.

Lanners are about the size of peregrines and they hate eagles just as much as our peregrines do.

The photographer, Steve Garvie, describes it this way:
“A pair of Lanner Falcons were nesting at one end of the cliffs and this massive female Verreaux’s Eagle drifted into their airspace. The female Lanner took to the air and quickly gained height then she flapped twice twisted onto her side then plunged in a deep stoop striking the circling eagle on the back of the head. The female eagle got a sore one and as the Lanner approached again she flipped upside down and clearly indicated there would be no second chance!”

Half a world away on June 6, 2012, Pitt’s famous peregrine Dorothy saw a bald eagle approach her “cliff” at the Cathedral of Learning.  She too flapped a couple of times and then attacked.  The bald eagle flipped upside down but it didn’t matter.  Dorothy won.

Eagles, whether Verreaux’s or Bald, can’t fly upside down for long.  Though Garvie doesn’t say it, I’m sure the lanner drove the eagle away just as Dorothy did at Pitt.

It’s Guess Who Won with an African twist.

(photo by Steve Garvie on Wikimedia Commons. Click on the photo to see the original)

Great gray owls (Strix nebulosa) live in coniferous forests and taiga of the North.  Their year-round range extends into upper Minnesota where this one was filmed in March.

In the video you’ll see two clips of the owl avoiding detection by two other species: a bald eagle and a raven.

It’s hard to imagine a large owl being afraid of anything, but he’s actually 15% smaller than a great horned owl.  He appears large because of his fluffy feathers.

In March he has a special reason for remaining hidden.  His nest is probably nearby.

Watch how the owl “gets skinny” to avoid being seen.

(Click here for more information on this video by Sparky Stensaas, Photonaturalist>)