Why Do Peregrines Like Bridges?

Hope (69/Z) at the Tarentum Bridge, July 2012 (photo by Steve Gosser)
Hope (69/Z) at the Tarentum Bridge, July 2012 (photo by Steve Gosser)

14 October 2016

When peregrine falcons look for a nest site they choose high places, often near water, with wide-open views of the surrounding landscape and lots of prey (birds).

Out in the wilderness, peregrines nest on sheer cliffs.  Pittsburgh doesn’t have cliffs but we do have nesting peregrines at on two buildings and many bridges.

It’s easy to see that a tall building resembles a cliff …

Cathedral of Learning (photo by Kate St. John)
Cathedral of Learning, 2015 (photo by Kate St. John)

… but bridges are open structures without sheer walls.

Tarentum Bridge nestbox project, The Bucket Truck, 27 Feb 2015 (photo by Kate St. John)
Tarentum Bridge, winter 2015 (photo by Kate St. John)

Why do peregrines like bridges?

I found the answer in a blog post from The Center for Conservation Biology (CCB). CCB monitors nesting peregrines in Virginia where many prefer bridges at the coast.

As you read the article linked below, watch for a photo of the Benjamin Harrison Lift Bridge where Hope (black/green, 69/Z) pictured above, was banded. She has nested at both kinds of sites in Pittsburgh:  six years at the Tarentum Bridge and now at a building, the Cathedral of Learning.

p.s. The article explains that peregrine nestlings from the Lift Bridge are hacked in the Shenandoah Mountains. Hope was one of those birds.

(credits are in the captions)

As High As A Jet

View from a jet crossing the Himalayas (photo by David Jones)
View from a jet crossing the Himalayas (photo by David C. Jones, Creative Commons license via Flickr)

Jet airplanes cruise at 30,000 to 40,000 feet.  Did you know that birds can fly at the low end of that range?

Birds’ respiratory systems are so efficient that they can pull oxygen out of very thin air.  We know this because they migrate over the Himalayas.

Common cranes (Grus grus) are widespread across Europe and Asia, nesting from Norway to Siberia and wintering from Africa to southern China.  Those that nest in eastern Kazakhstan and northwestern China fly over the Himalayas to spend the winter in India.  They’ve been clocked at 33,000 feet!

Common cranes in flight (photo by Ján Svetlík)
Common cranes in flight (photo by Ján Svetlík, Creative Commons license via Flickr)

Bar-headed geese (Anser indicus) nest in the Tibetan highlands and spend the winter in the lowlands of India. The shortest route from Tibet to the sea is to fly directly over the Himalayas, and so they do.  They’ve been recorded at 29,600 feet and seen flying over Mount Everest!  This video describes how they do it and asks questions for further study.

And even mallards, the ubiquitous ducks that eat bread at the boat launch, were seen migrating at 21,000 feet over Nevada.

Mallards in flight (photo by Ken Slade, Creative Commons license via Flickr)
Mallards in flight (photo by Ken Slade, Creative Commons license via Flickr)

Birds don’t need oxygen masks at those high altitudes.  They just fly by.

(photo credits: All photos are Creative Commons licensed via Flickr. Click on each image to see its original:View from a jet over the Himalayas by David C. Jones on Flickr, Common cranes in flight by Ján Svetlík on Flickr, Mallards in flight by Ken Slade on Flickr, Video from FantasticAnimal on YouTube)

Similar Sapsuckers

Yellow-bellied sapsucker (photo by Cris Hamilton)
Yellow-bellied sapsucker (photo by Cris Hamilton)

Now that yellow-bellied sapsuckers (Sphyrapicus varius) are migrating through western Pennsylvania I’m reminded of three sapsucker species we’ll never see unless we travel west.

 

The red-naped sapsucker (Sphyrapicus nuchalis) resembles a yellow-bellied except that his nape (the back of his head) is red.  He lives among trees in the Mountain Time zone all the way to the Sierras and Cascades.  Amazingly, his range only overlaps the much larger range of the yellow-bellied sapsucker at a few sites in Canada — so you can identify him by location in the U.S.

Red-naped sapsucker (photo by J. Maughn, Creative Commons license via Flickr)
Red-naped sapsucker (photo by J. Maughn, Creative Commons license via Flickr)

 

The red-breasted sapsucker (Sphyrapicus ruber), native to far western North America, looks as if he’s been dipped in tomato juice. His range sometimes overlaps the western edges of yellow-bellied and red-naped sapsuckers with whom he sometimes interbreeds.  The hybrids look like sapsuckers partially dipped in tomato juice. 😉

Red-breasted sapsucker (photo by Jacob McGinnis, Creative Commons license via Flickr)
Red-breasted sapsucker (photo by Jacob McGinnis, Creative Commons license via Flickr)

And finally, male Williamson’s sapsuckers (Sphyrapicus thyroideus) can’t be mistaken for any other bird.  Sporting a black head and chest and a bright yellow belly, these sapsuckers live in middle to high elevation western mountains.  I’ve never seen one.

Williamson's sapsucker (photo by Ken Schneider, Creative Commons license via Flicker)
Williamson’s sapsucker (photo by Ken Schneider, Creative Commons license via Flicker)

 

Watch for yellow-bellied sapsuckers passing through western Pennsylvania on their way south.  In eastern Pennsylvania, they stay all winter.

 

(photo credits:  Yellow-bellied sapsucker by Cris Hamilton. Red-naped sapsucker by J. Maughn, Creative Commons license via Flickr. Red-breasted sapsucker by  Jacob McGinnis, Creative Commons license via Flickr. Williamson’s sapsucker by Ken Schneider, Creative Commons license via Flicker)

 

Why Are We Thirsty Before We Sleep?

Glass of water (photo by Kate St.John)
Tall glass of water (photo by Kate St.John)

10 October 2016

Have you noticed that you’re thirsty before you go to sleep?  Why is that?

A recent study published in the journal Nature might not provide the answer for humans but it sounds plausible to me.

Researchers at McGill University noticed that two hours before they went to sleep mice drank more water than they actually needed.  The scientists restricted access to water before bedtime and the mice became dehydrated while they slept.  Obviously drinking water ahead of time is a survival mechanism.

Pet mouse taking a drink (photo from Wikimedia Commons)

But how did the mice know to drink so much?  Using ingenious tests the research team found that the animal’s biological clock was sending a “drink water” signal to the brain’s thirst center.

I’ll bet this is true of humans, too.  My biological clocks says, “Drink water” and so I do.

Read more about the study here in Science Daily.

(photo by Kate St. John)

Reminder: Schenley Park Outing, Oct 16

Maple leaves turning red, Schenley Park, 5 Oct 2012 (photo by Kate St. John)Just a reminder that I’ll be leading this year’s final Schenley Park Bird and Nature Walk on Sunday October 16, 8:30a to 10:30a.

Meet at Bartlett Shelter on Bartlett Street near Panther Hollow Road.

Dress for the weather and wear comfortable walking shoes. Bring binoculars and field guides if you have them.

Fall colors have just begun and sparrows are migrating.  We’ll see resident birds and lots of chipmunks.

Click here for more information and in case of cancellation.

(photo by Kate St. John)

 

Favored By Cardinals

Climbing false buckwheat (photo by Kate St. John)
Climbing false buckwheat (photo by Kate St. John)

This vine looks messy but its seeds are good food for birds and mammals.

Though climbing false buckwheat (Fallopia scandens a.k.a. Polygonum scandens) is related to smartweed and Japanese knotweed, it’s a native perennial vine. Unfortunately it looks invasive because its red stems climb over nearby vegetation to get close to the sun.

Its small whitish flowers bloom from August to October but they aren’t much to look at.

Climbing false buckwheat (photo from Flora Pittsburghensis)
Climbing false buckwheat (photo from Flora Pittsburghensis)

Last week in Schenley Park I found a chipmunk and four cardinals hiding among the tangled vines, quietly munching false buckwheat seeds.

The seeds are favored by cardinals.

 

(seed photo by Kate St.John. Flower photo from Flora Pittsburghensis; click on the photo to see the original)

A Visit to Elk Country

Bull elk grazing in a front yard in Elk County, 4 Oct 2016 (photo by Kate St.John)
Bull elk grazing in a front yard in Elk County, Pennsylvania, 4 Oct 2016 (photo by Kate St.John)

Last Tuesday Geralyn Pundzak, Kathy Miller and I made a one day trip to see the elk near Benezette, PA.  During the rut, September-October, the males pursue the ladies, spar with other males and “sing” a bugling love song.

Our first two stops came up empty and we began to worry that we’d miss them.  Geralyn, who drove us there, said she wouldn’t leave until she saw an elk. The pressure was on!

At Woodring Farm we heard an elk bugling on the hill above us.  He soon crossed the gravel road only 100 yards away, then stopped to bugle among the trees.  I was so excited I forgot to take pictures.

On our way to Dents Run we saw an elk lying down, almost on a front porch. Was he a statue?  No, his head moved!  We returned to an elk traffic jam and took these photos.

Bull elk in Elk Country, 4 Oct 2016 (photo by Kate St. John)
Bull elk in Elk Country, 4 Oct 2016 (photo by Kate St. John)

Bull elk grazing in a front yard, 4 Oct 2016 (photo by Kate St. John)
Bull elk grazing in a front yard, 4 Oct 2016 (photo by Kate St. John)

Bull elk in Elk Country, Pennsylvania, 4Oct 2016 (photo by Kate St. John)
Bull elk in Elk Country, Pennsylvania, 4 Oct 2016 (photo by Kate St. John)

In addition to the elk we enjoyed birding, scenic overlooks, and the Field of Flowers at Woodring Farm.

A view of Elk County from Woodring Farm overlook (photo by Kate St. John)
Elk County view from Woodring Farm overlook (photo by Kate St. John)

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At the Field of Flowers, Woodring Farm, Elk County, PA, 4 Oct 2016 (photo by Kate St.John)
At the Field of Flowers, Woodring Farm, Elk County, PA, 4 Oct 2016 (photo by Kate St.John)

Visit Elk Country now while the elk are bugling and the leaves are changing.

 

(photos by Kate St. John)

Super Hummingbirds Next Week

screenshot from Super Hummingbirds video by PBS NATURE
screenshot from Super Hummingbirds video by PBS NATURE

Tiny and jewel-like, hummingbirds are “super-birds.”  They beat their wings 80 times per second and fly backwards and upside down.  And that’s only the start.

Next Wednesday we’ll get to see these super birds at their best on PBS NATURE’s season premiere: Super Hummingbirds.

Filmed in Colombia, Peru and Costa Rica, the program showcases surprising information about hummingbirds’ lives.

  • Their tongues open lengthwise to gather nectar using unique forked tips.
  • Many live high-speed lives in thin air at 16,000 feet in the Andes Mountains.
  • Male long-billed hermit hummingbirds in Costa Rica gather in leks to sing for a mate.

A side trip to Arizona captured the Costa’s hummingbird courtship ritual.  During the male’s sky dance he splays out his purple gorget to impress his potential mate.  The screenshot below is just a hint at his beauty.  He’s amazing in the video.

Male Costa's hummingbird sky-dances for a female (screenshot from PBS NATURE's Super Hummingbirds)
Male Costa’s hummingbird sky-dances for a female (screenshot from PBS NATURE’s Super Hummingbirds)

Watch Super Hummingbirds next Wednesday, October 12, 2016 on PBS NATURE at 8pm (Eastern time). In Pittsburgh, it’s on WQED.

And while you’re waiting for next Wednesday, get your “hummingbird fix” at Cornell Lab’s West Texas Hummingbird Cam near Fort Davis, Texas. Click here to watch.

 

(Super Hummingbirds video and screenshot from PBS NATURE)