Archive for the 'Bird Behavior' Category

Aug 08 2016

Asleep In Flight

Published by under Bird Behavior

Great frigatebird carrying sleep monitoring equipment (photo by Bryson Voiron from Nature Communications article)

Great frigatebird with sleep monitoring equipment (photo by Bryson Voiron from Nature Communications article)

On transoceanic airplane trips the passengers try to sleep in flight but the pilots stay awake. (Thank heaven!)  Many birds, including swifts, sandpipers and songbirds, fly non-stop over the ocean for so long that scientists guessed the birds would have to sleep along the way.  But how? Wouldn’t they crash?

As part of their daily lives, great frigatebirds (Fregata minor) fly non-stop for weeks, eating flying fish and ocean-surface food in trips that can span two months and 22,000 miles.  These large birds live over the ocean but not on it because their feathers aren’t waterproof.

Great frigatebirds have got to sleep some time so researchers led by Niels C. Rattenborg of the Max Planck Institute fitted more than a dozen females with instruments to measure sleep and flight time.  The great frigatebird, above, has a sleep-measuring headset and a GPS backpack.

The results of the sleep study were surprising.

Scientists knew that, on land, birds can sleep with only half the brain while the other half stays alert for danger. They found that great frigatebirds half-sleep in the air, too, but sometimes both hemispheres sleep at once for more than two minutes.  They do it while circling on an updraft.

Another surprise was how little the birds slept, clocking only 42 minutes/day in the air compared to 12 hours/day on land.  If they were humans they’d be seriously sleep deprived.

Amazingly the frigatebirds’ performance was not affected by lack of sleep and when they got home they caught up on sleep in their first days on shore.  How many of us wish we could live like that!

Find out more here at Gizmodo or in the report here in Nature Communications.

 

(photo of great frigatebird with sleep measuring equipment by Bryson Voiron from  “Evidence that birds sleep in flight,” Nature Communications)

No responses yet

Aug 05 2016

His Feathers Sing

The male club-winged manakin (Machaeropterus deliciosus) uses dance and sound to attract the ladies but he doesn’t open his mouth.  He uses his wings!

Watch and listen as he bows and flares.  The loud buzzy noise is made by his secondaries.  Cornell Lab writes:

The secondary wing feathers of the male Club-Winged Manakin, a bird from South America, are large and rigid. He strikes them together at about 107 times per second to create a buzzing sound, which is used during courtship displays.

Ornithologists have known for a long time that the males’ secondary feathers are deformed.  This 1871 drawing shows the difference between the males’ deformed and the females’ normal feathers.

Modification of Manakin Pipra deliciosa = Machaeropterus deliciosus wings for sound production, from Darwin's - The Descent of Man

Modification of Manakin Pipra deliciosa = Machaeropterus deliciosus wings for sound production, from Darwin’s – The Descent of Man

 

Now that we have high definition video we can see why they’re like that.  He makes his feathers sing.

 

p.s.  Click here for the location of secondary wing feathers.

(video from Cornell Lab of Ornithology on YouTube. Illustration from Wikimedia Commons; click on the image to see the original.)

One response so far

Jul 30 2016

Summer Pair Bonds

Dori and Louie bow at the Gulf Tower nest before dawn, 30 July 2016 (photo from the National Aviary falconcam at Gulf Tower)

Dori and Louie bow at the Gulf Tower nest before dawn, 30 July 2016 (photo from the National Aviary falconcam at Gulf Tower)

In late July, the nesting season is over but Pittsburgh’s adult peregrines still see each other every day and sometimes visit the nest to bow and cement their pair bonds.

The Downtown pair, Dori and Louie, are especially early risers.  Here they are this morning, Saturday July 30 at 5:53am.  In the distance you can see the sky lighting up in the east and the silhouette of the Cathedral of Learning.  The sun rose at 6:16am.  (They also visited before dawn on July 24.)

The Cathedral of Learning peregrines aren’t such early birds but they’re bowing too.  Sometimes Hope is impatient for Terzo to join her at the nest.  Below, she shouts, “Come here!” on 25 July at 8am.

Hope shouts, "Come here!" to Terzo, 25 July 2016 (phto from the National Aviary falconcam at Univ of Pittsburgh)

Hope shouts to Terzo, “Come here!”, 25 July 2016 (photo from the National Aviary falconcam at Univ of Pittsburgh)

Yesterday they bowed twice — at 4:11pm and 6:22pm, July 29.  Here’s their second session.

Tezro and Hope bow at the Pitt peregrine nest, 29 July 2016 (photo from the National Aviary falconcam at Univ of Pittsburgh)

Tezro and Hope bow at the Pitt peregrine nest, 29 July 2016 (photo from the National Aviary falconcam at Univ of Pittsburgh)

Now that the “kids” have grown and flown, the adults spend time with each other.

 

(photo from the National Aviary falconcam at the Gulf Tower)

10 responses so far

Jul 29 2016

Urban Birds Have It All

Peregrine falcon, Dorothy, at the Cathedral of Learning, Feb 2011 (photo by Patricia Szczepanski)

Peregrine falcon, Dorothy, at the Cathedral of Learning in February 2011 (photo by Patricia Szczepanski)

Twenty-five years ago peregrine falcons moved into the City of Pittsburgh.  Since then lots of cool raptors have come here, too, including red-tailed hawks, Coopers hawks, turkey vultures and, most recently, bald eagles.

City living provides food and protection from predators but birds face new challenges by living near humans.  Jean-Nicolas Audet of McGill University wondered if these challenges put city birds at a disadvantage compared to their country cousins so he designed some tests to answer these questions:  Which group is better at problem solving? Which group is more immune to disease?  And since both traits require lots of energy, is there a trade-off such that smarter birds have lower immunity?

The Caribbean island of Barbados has both city and country habitats and an endemic species that lives in both places, the Barbados bullfinch (Loxigilla barbadensis).  Audet tested the bullfinches and the results were surprising.

“We found that not only were birds from urbanized areas better at innovative problem-solving tasks than bullfinches from rural environments, but that surprisingly urban birds also had a better immunity than rural birds,” says Jean-Nicolas Audet, a Ph.D student in the Department of Biology and first author of the study published in the journal Behavioral Ecology in 2016.

As earth’s human population grows and more habitat is converted to cities, more birds may have to choose the urban environment.  If they can adapt, it will be a smart move.  As Audet says, “Urban birds have it all.”

 

Read more about the 2016 study and find links here to The town bird and the country bird: problem solving and immunocompetence vary with urbanization.

(photo of Dorothy in 2011 by Patricia Szczepanski. video from McGill University on YouTube)

2 responses so far

Jul 28 2016

Drinking Techniques

Italian Sparrows in Bolzano, Italy (photo from Wikimedia Commons)

Sparrows take a sip in Bolzano, Italy (photo from Wikimedia Commons)

On Throw Back Thursday:

Like us birds drink more water in the summer heat.  Have you noticed they use different drinking techniques?  Some drink with faces down, others tilt their faces up.

These house sparrows appear to be using the face-down technique on a martini.  But wait!  The glass held ice cream and they’re picking at the remains.   So what do they really do?

Find out how birds drink in this vintage article from 2010:

Anatomy: How Birds Drink

 

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

No responses yet

Jul 22 2016

Purple Martins: Faithful to Home

Purple martin fledgling opens wide for dad (photo by Donna Foyle)

Purple martin fledgling opens wide for dad (photo by Donna Foyle)

Last Saturday fourteen of us joined purple martin landlords and their families at Bob Allnock’s annual Purple Martin Night where we learned about the birds and heard news of their success.

Click here for the slideshow that illustrates this article.

Purple martins (Progne subis) are North America’s largest swallow and the only bird that relies on man-made housing for its nest.  The western population still uses woodpecker holes but eastern purple martins made the switch long ago to nest colonially in apartments and man-made gourds provided by human landlords.

Purple martin houses at Bob Allnock's (photo by Kate St. John)

Purple martin houses at Bob Allnock’s (photo by Kate St. John)

The landlords provide housing and protection and the martins return faithfully every year.  The dark blueish purple males arrive first — in April in western Pennsylvania — followed by the adult females with dark backs, light bellies and gray collars.  The adults claim their favorite nest sites before the speckled sub-adults arrive.

Purple martins eat only flying insects and are especially fond of dragonflies.  To catch them they feed higher in the sky than other swallows.  We didn’t think the martins were anywhere near us until we looked up at the clouds with our binoculars and saw them wheeling as much as 500 feet above.

Female purple martin with food for her nestlings (photo by Donna Foyle)

Female purple martin with food for her nestlings (photo by Donna Foyle)

By mid-July many of the young martins in Bob’s colony had already fledged but they still begged from their parents.   The (approx) 80 nest sites were humming with activity as the adults fed youngsters, took out the garbage (fecal sacs), and sometimes even tussled at the nest holes.  One youngster (see him in gourd #2) fledged while we were there.

Like all birds, purple martins are vulnerable to nest predation and a variable food supply. Fortunately they have dedicated landlords who …

  • Check the nests to make sure all is well. In the slideshow notice the circular access lid on the gourds. Bob Allnock can also watch three nests on nestcams.
  • Protect the nests from starlings by providing M-shaped holes that only purple martins can use.
  • Thwart raccoons and snakes who climb the poles to raid the nests.  Bob Allnock has wrapped the base of his poles with live electric wiring (“electric fence”).  One shock is all it takes!
  • Scare off great horned owls who raid from the air.  Bob turns on a yellow “air dancer” at dusk.  He moves it to a new location every night so the owls don’t get wise to it.
  • Provide supplemental feeding during prolonged wet weather when the bugs don’t fly. Purple martins starve without these feedings.

And the weather has cooperated.  This year’s fledglings are doing well in western Pennsylvania’s dry weather, especially after three wet years in a row.

Until their young have learned the ropes the purple martins stay at the colony.  At dusk they return to spend the night inside the nests.

In September they’ll leave for Brazil and their landlords will wait through the long quiet winter for their faithful purple martins to come home.

Click here for a slideshow of the event.

 

(All the purple martin close-ups are by Donna Foyle. House photos by Kate St. John.  Image of yellow inflatable air dancer from Amazon.com)

6 responses so far

Jul 15 2016

Old Home Week for the Downtown Peregrines

Dori and Louie bow at the Gulf Tower nest, 14 July 2016, 3:48pm (photo from the national Aviary falconcam at Gulf Tower)

Dori and Louie bow at the Gulf Tower nest, 14 July 2016, 3:48pm (photo from the national Aviary falconcam at Gulf Tower)

Yesterday (July 14) was Old Home Week for the Downtown peregrines as they toured all the places they’ve nested since Dori arrived in Pittsburgh six years ago.

Around 7:30am Lori Maggio saw “an adult peregrine, Dori I assume, preening on the 3rd Ave nest ledge. Then she entered the nest.”  The photo below from last May gives you an idea of what Lori saw. The peregrines nested here in 2012, 2013 and this year, 2016.

adult peregrine at entrance to Third Ave nest in May 2016 (photo by Lori Maggio)

Adult peregrine at entrance to Third Ave nest in May 2016 (photo by Lori Maggio)

 

At 10:55am Dori and Louie visited their 2015 nest at the old Macy’s Annex.  Matt Digiacomo, who captured these photos, says the area is under renovation.  The door is open on the balcony behind Dori so she’s not likely to nest here.  Perhaps she was curious.

Dori visiting her 2015 nest site at the former Macy's Annex, 14 Jul 2016 (photo by Matt Digiacomo)

Dori visiting her 2015 nest site at the former Macy’s Annex, 14 Jul 2016 (photo by Matt Digiacomo)

And perhaps Louie was curious, too.  While Dori checked out Macy’s, he perched at his usual overlook on the Union Trust Building.  I’m sure he’s glad the Union Trust scaffolding is gone.

Louie at his usual perch on the Union Trust Building, 14 July 2016 (photo by Matt Digiacomo)

Louie at his usual perch on the Union Trust Building, 14 July 2016 (photo by Matt Digiacomo)

 

Finally at 3:48pm the pair rounded out their tour with a bowing visit to the Gulf Tower, at top.  Dori nested here in 2010, 2011 and 2014.

All of Dori’s predecessors — and Dori herself — used the Gulf Tower continuously from 1991-2011.  It’s a mystery why she’s so nomadic.

 

(photos from the National Aviary falconcam at Gulf Tower, Lori Maggio and Matthew Digiacomo)

 

2 responses so far

Jul 11 2016

A Bird With A Bad Pick-up Line

This 3-note song mystified me in my own backyard.  I can usually identify birds by ear but this one stumped me for at least six weeks.

Finally, I recorded it outside my window and sent it to my friend Dr. Tony Bledsoe.  Tony suggested a tufted titmouse. (Turn up your speakers to hear the song in the video above. Ignore the picture, the bird’s not in it.)

A few days later I saw the bird.  No wonder we didn’t recognize the song!  He’s a gray catbird that sounds nothing like his cohorts.  (Turn your speakers back down for the audio below.)

 

Most birds are silent in early July but the odd-sounding gray catbird is still singing in my neighborhood and I can guess why.

None of the lady catbirds like his song so he’s still calling for a mate.

He’s a bird with a bad pick-up line.

 

(video by Kate St. John)

2 responses so far

Jul 05 2016

Hope’s in Charge For Now

Hope and Terzo band colors showing, 4 July 2016(photo from the National Aviary falconcam at Univ of Pittsburgh)

Hope and Terzo with band colors showing, 4 July 2016 (photo from the National Aviary falconcam at Univ of Pittsburgh)

A lot has happened at the Cathedral of Learning peregrine nest in the past two weeks.

  • On June 21 a new female peregrine, Magnum, appeared on the falconcam. She came to the nest several times through June 23 and bowed with Terzo, the resident male. Her presence meant that the previous female, Hope, was gone.
  • At midday June 24 Hope returned to the nest and has been bowing with Terzo ever since.
  • On June 27 this year’s fledgling, C1, visited the nest and made loud begging sounds.
  • On July 2, Chad Steele photographed Magnum at her own nest site, the Neville Island I-79 Bridge.

During these changes I was off the grid and couldn’t answer your questions.  Here are some long awaited answers.
.
Did anyone see Hope and Magnum fighting?

No. We never saw anything, stuck on the ground with our poor field of view.  My guess is that Hope and Magnum chased each other without making physical contact.

I see two peregrines at the nest. Please tell me if it’s Hope and Magnum and if they are fighting.

Magnum is gone for now.  However, you can tell the difference between courtship and fighting by observing the birds’ postures and actions:

Courtship: Two peregrines standing apart from each other, chirping and bowing low = male+female strengthening pair bond.  This is good.

Fight: Two peregrines with talons locked (feet are connected), trying to peck at each others’ throats, wings open, leaning backwards to avoid each others’ beaks = 2 birds of the same sex fighting.  Here’s a slideshow of a fight in 2007 between two males at the Cathedral of Learning.

Why are the females competing now outside the nesting season? Are they competing for Terzo?

They’re not competing for Terzo at all.  They’re competing for the Cathedral of Learning, a prime nest site worth winning at any time of year. It’s better than a bridge.

Does Terzo’s preference determine which female wins?  Since Hope was there first, will Terzo leave if he prefers Magnum?

No. Unlike humans who bond with their mates and then find a place to live, peregrines bond to the nest site and then mate with whoever is there.  If another female wins the site — no matter who it is — Terzo will mate with that female. He will not leave the site unless a new male ousts him.

Will Hope keep the Cathedral of Learning site?

We don’t know.  We can tell that Hope is a weak owner because other females have made it to the nest three times in April & June.  A strong owner would never let other females get into the nest.  It never happened during Dorothy’s reign.

Has anyone seen Magnum recently?

Yes. On July 2 Chad Steele, peregrine monitor from Canton, Ohio, photographed Magnum at her home nest site, the Neville Island I-79 Bridge.  His photos confirm her identity.

Magnum at the Neville Island I-79 Bridge, 2 Jul 2016 (photo by Chad Steele)

Magnum at the Neville Island I-79 Bridge, 2 Jul 2016 (photo by Chad Steele)

.
How is this year’s fledgling, C1?

C1 is so mobile that it’s hard to keep track of her.  Anne Marie Bosnyak saw her this morning, July 5, on St. Paul’s steeple.  We also know she visited the nest on June 27, whining loudly. Is she as loud as her mother? Perhaps.

C1 visits the nest, 27 June 2016 (photo from the National Aviary falconcam at Univ of Pittsburgh)

C1 visits the nest, 27 June 2016 (photo from the National Aviary falconcam at Univ of Pittsburgh)

 

p.s. As you watch the falconcam, here are band colors and numbers to look for:
Hope: black/green 69/Z + Green on right leg
Terzo: black/red N/29 + Silver on right leg
Magnum: black/red 62/H + Purple on right leg
C1 (juvenile, brown and cream-colored plumage): black/green 06/BR + Silver on right leg

(nest photos from the National Aviary falconcams at Univ. of Pittsburgh. photo of Magnum in flight by Chad Steele)

11 responses so far

Jun 28 2016

There’s A Lot Less Singing

Yellow warbler (photo by Chuck Tague)

Yellow warbler (photo by Chuck Tague)

It happens every year. By late June, birds are singing a lot less than they did a month ago. By mid July most birds are silent.

Find out why they stop singing in this article: Becoming Silent.

 

(photo by Chuck Tague)

No responses yet

« Prev - Next »