Archive for the 'Bird Behavior' Category

May 06 2015

Warblers Fled Tornadoes One Day Ahead!

Published by under Bird Behavior

F5 Tornado approaching Elie, Manitoba on June 22, 2007 (photo by Justin Hobson via Wikimedia Commons)

Just over a year ago a violent storm system spawned 84 tornadoes that ripped through the central and southern U.S. on April 27-30, 2014.  Because of the storms’ advanced warning, ornithologists learned an amazing thing about birds.

In the previous year, Dr. Henry Streby and researchers from the Universities of Tennessee and Minnesota had placed geolocators on 20 golden-winged warblers nesting in the northeast mountains of Tennessee.

Golden-winged warbler (photo from Wikimedia Commons)

Golden-winged warbler (photo from Wikimedia Commons)

The tiny devices had recorded information while the warblers migrated and now, in late April, it was time to recapture the birds and retrieve the data.

During that fateful week in April, the researchers had found 10 of the warblers in Tennessee and were about to capture them when they learned of the storm and left the mountain to wait it out.

The storm was very bad!  It roared through Kansas and Arkansas on April 27, generated this radar image in Tennessee on April 28 (click image for a closeup), and then dumped heavy rain on April 30.

Weather radar of EF3 tornado, Lincoln County, TN, 28 April 2014 (NWS via Wikimedia Commons)

Weather radar of EF3 tornado, Lincoln-Moore County, TN, 28 April 2014 (NWS via Wikimedia Commons)

When the violent weather was over, the researchers went back up the mountain and captured five golden-winged warblers wearing geolocators.  In the months that followed they downloaded and processed the data to chart the birds’ course.

And here’s the amazing thing:  The data showed that the birds spent the winter in Colombia as expected, but there was an aberration just before the geolocators were retrieved.  One to two days before the tornadoes struck, all five birds sensed the storms were coming and evacuated 400 miles southward — all the way to the Gulf of Mexico, just outside the danger zone.  When the storms were over, they flew back to Tennessee and were back on territory by May 2.

The tornadoes’ low-frequency sound gave the warblers a long-distance cue.   They heard it and fled!  The researchers speculate that other birds do this, too.

Read more here in BBC Science News.

 

(photos from Wikimedia Commons. Click on the images to see the originals.  F5 Tornado in Elie, Manitoba, June 2007, by Justin Hobson.  Golden-winged warbler by Andy Reago.  Radar image from National Weather Service of F3 tornado in Lincoln-Moore County, TN, April 28, 2014)

p.s.  To see the size of a geolocator on a warbler, here’s a blackpoll warbler wearing a geolocator.

3 responses so far

Apr 09 2015

Location, Location, Location: PBS NATURE April 15


Last night we learned about nests on PBS NATURE‘s Animal Homes.  Next Wednesday Episode 2 will take us inside bird and mammal homes chosen for their prime locations.  Tune in at 8:00pm EDT to learn:

  • When beavers hear running water they feel compelled to build. Once started they alter the landscape and never stop improving their dams, canals, lodges and storage facilities.  Did you know they move rocks?
  • Hooded mergansers nest in hollow trees 50 feet above the forest floor.  When the “kids” leave the nest, watch out below!
  • Find out why eastern woodrats are called “packrats.”
  • Learn that the safest place to build a black-chinned hummingbird nest is near the ultimate enemy.
  • Visit a bear den in the Allegheny Mountains of Garrett County while Maryland DNR tags a black bear mother with four cubs.  How do you keep bear cubs warm while their mother is “out cold?”  Cuddle them!

Watch Animal Homes: Location, Location, Location on PBS NATURE, April 15 at 8:00pm EDT.  In Pittsburgh it’s on WQED.

 

(video from PBS Nature, Animal Homes Episode 2, Location, Location, Location)

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Mar 28 2015

Mixed Parentage

Redhead-Ring-necked Duck hybird, Duck Hollow, Pittsburgh, PA, 25 Mar 2015 (photo by Tom Moeller)

Redhead-Ring-necked hybrid duck at Duck Hollow, Pittsburgh, PA, 25 Mar 2015 (photo by Tom Moeller)

What duck is this?

Photographed by Tom Moeller on March 25 at Duck Hollow in Pittsburgh, this odd duck defies a single label.  Apparently one of his parents was a redhead, the other a ring-necked duck.

Here are the two species he resembles: male redhead on the left, male ring-necked duck on the right.

Two male ducks: Redhead and Ring-necked (photos by Chuck Tague)

Two male ducks: Redhead and Ring-necked (photos by Chuck Tague)

He has the head color, eye color and shoulder of a redhead and the head shape, bill color and body color (except for his non-white shoulder) of a ring-necked duck.

Depending on the light and the distance you might see a feature of either species and call him accordingly.  David Poortinga figured him out and told Tom what it was.

Here’s another look him.  He’s a redhead with a fancy bill and black back.  Or he’s a ring-necked duck with a red head.

Redhead-Ring-necked Duck hybird, Duck Hollow, Pittsburgh, PA, 25 Mar 2015 (photo by Tom Moeller)

Redhead-Ring-necked Duck hybrid, Duck Hollow, Pittsburgh, PA, 25 Mar 2015 (photo by Tom Moeller)

Ducks and geese hybridize a lot compared to other birds.  Duck hunters see these hybrids up close because they have the bird in hand so Ducks Unlimited explains:

“Waterfowl crossbreed more often than any other family of birds. Scientists have recorded more than 400 hybrid combinations among waterfowl species. Mallards crossbreed with nearly 50 other species, and wood ducks hybridize with a surprising 26 other species. Nearly 20 percent of waterfowl hybrid offspring are capable of reproducing.”

Mallards being the least picky, or the perhaps most promiscuous, breed with many species.  According to Ducks Unlimited their mates include northern pintails, black ducks, wigeon, shovelers, cinnamon teal, green-winged teal, and gadwalls.  Perhaps every dabbling duck is a mallard at heart.

Will the Odd Duck attract a mate this spring ?  If so, will she be a redhead or a ring-necked duck?  What will his offspring look like?

Yikes!  Talk about mixed parentage!

 

p.s. As of yesterday, March 27, the hybrid was still at Duck Hollow.

(photo of hybrid Redhead-Ring-necked Duck by Tom Moeller.  Composite photos of redhead and ring-necked ducks by Chuck Tague)

3 responses so far

Mar 24 2015

The Scouts Are Coming

Adult male purple martin (photo by Cajay on Wikimedia Commons)

You know Spring has sprung when the swallows return.  Tree swallows arrive first (seen in Allegheny County already!) but soon the bravest purple martins return from Brazil.  Though they rely on flying insects for food, adult males are so anxious to begin breeding that they fly home as soon as they can.

Purple martins (Progne subis) are cavity nesters with a long term relationship to humans.  Native Americans first provided nesting gourds and European immigrants followed suit so that now, for more than 100 years, all the purple martins in eastern North America nest in human provided housing.

Purple Martin house, Cape May Point, NJ (photo from Wikimedia Commons)

Last Thursday at Wissahickon Nature Club Bob Allnock, a purple martin landlord from Butler County, taught us about the housing and habits of these amazing birds.  We learned that the same purple martins return year after year to their successful nest sites.   The earliest males get the best condos so they hurry to get home.  The landlords call them “scouts.”

Scouts are always adult males who’ve bred before and know exactly where they’re going.  Adult females return later and then, weeks later, the subadult males and females arrive.  They’re in their first year of breeding and haven’t found a home yet.  If you’re trying to establish a new purple martin colony, these are the birds you wait for.

Right now purple martin landlords in western Pennsylvania are anxiously awaiting their first scouts.  As soon as one arrives the landlord updates the Purple Martin Conservation Association (PCMA) website with the date and location.  They also update when they see the first subadults so that landlords of unoccupied colonies can be on the lookout to attract these new birds.

How far north has Spring advanced? Where are they scouts right now?  Click here on the PCMA website for the Scout Report.

 

(photos from Wikimedia Commons. Click on the images to see the originals)

2 responses so far

Mar 14 2015

Not a Statue

Published by under Bird Behavior

Grey heron sunbathing (photo by SteveValasek)

This is not a statue.

It’s a grey heron sunbathing with his wings in a circle to catch the maximum rays.

Grey herons look a lot like our great blue herons though they live in Europe and Asia.  Steve Valasek took this picture in Ireland.

Love those wings!

 

(photo by Steve Valasek)

3 responses so far

Mar 10 2015

Ladies Make Do In A Pinch

Laysan albatross adults dance (photo from Wikimedia Commons)

Out in the Pacific there are more female Laysan albatrosses than males.  The males will mate with the extra females but it takes two parents to raise the chick.  A single mom can’t raise her chick alone.  What’s a girl to do?

A long term study of Laysan albatrosses, published in 2008, shows that the extra females pair up in reciprocity agreements.

Albatrosses are such big birds that it takes a whole year for their solo chicks to mature and fledge.  Rearing the chick takes so long and is so labor intensive that female albatrosses lay one egg every other year.

Without a mate to help with nest duty the chick will die.  Researchers on Oahu, where the Laysan albatross population is 59% female, discovered that unrelated females on opposite fertility cycles pair up and raise each others’ chicks.  At the start, only one of them lays an egg and the pair incubates and raises the chick together.  When it’s egg-laying time again, the other female takes her turn.

Though their nesting success is lower than for male-female pairs, it works well enough that these girlfriends stay together for many years.

Ladies make do in a pinch.

Read more here at Science Daily.

 

p.s. Watch a Laysan albatross nestcam in Kauai, Hawaii on Cornell Lab’s website.  The chick is huge!

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

5 responses so far

Mar 04 2015

Selective Attention In Chickens

Chicken (photo by Luis Miguel Bugallo Sánchez via Wikimedia Commons)

I love the title but … What the heck is Selective Attention and who cares about it in chickens?   (Don’t worry, there’s fun at the end.)

Selective attention — the ability to focus in the midst of distractions — is something we humans do well.  For instance, we can listen to one person in a crowded noisy room and focus completely on what they’re saying, tuning out everything else.  This is useful!

Selective attention has been studied extensively in primates.  Do birds possess this skill?

Anecdotally, I’d say “Yes.”  I’ve watched red-tailed hawks keenly focused while hunting next to busy roads.  They tune out all the traffic and successfully catch their prey.  Unfortunately some are way too good at ignoring traffic and are struck and killed by vehicles.

No one had proven selective attention in birds until researchers at Stanford University’s School of Medicine gave chickens quick visual cues to see if they would peck outside the (virtual) box.  Published in Proceedings of the National Academy of Sciences in 2014, “The results show that chickens shift spatial attention rapidly and dynamically, following principles of stimulus selection that closely parallel those documented in primates.”

Watch the chicken peck the X in the middle. Then a quick flash of light attracts his attention.  Birds and primates both inherited this cognitive skill.

And now a quiz for you:  Remember how I said red-tailed hawks are sometimes hit by cars because they’re focusing so much?  Watch this video to test your own selective attention.

… and you’ll understand the red-tail’s problem.

 

(chicken photo by Luis Miguel Bugallo Sánchez from Wikimedia Commons.  Click on the image to see the original.)

10 responses so far

Feb 17 2015

Who Made This Hole?

Pileated woodpecker hole in dead white ash tree, Pennsylvania (photo by Kate St. John)

Sometimes you can tell who drilled a hole just by looking at it.

This one caught my eye at Raccoon Creek State Park.  I can tell by its big, rectangular shape that it was made by a pileated woodpecker.

Pileated woodpeckers (Dryocopus pileatus) are the size of crows, mostly black with white on their necks and faces, white on their wings (seen in flight) and a red crest. Males, like the one below, have red foreheads and mustaches where the females are black.

Male Pileated Woodpecker (photo by Dick Martin)

Male pileated woodpecker (photo by Dick Martin, 2009)

These are huge woodpeckers! And so are their holes.  Here’s a closer look.

Pileated woodpecker hole in deah ash tree (photo by Kate St. John)

As you can see, the hole is oblong — about 9″ tall by 3.5″ wide — and hollow inside.  The male chooses the site and excavates the interior, gathering wood chips in his beak and throwing them out the “door.”  Eventually his mate helps, too.  It takes them 3-6 weeks to finish a new nest hole each spring.

They only use the nest for one season, but nothing goes to waste.  Pileated woodpeckers stay on territory all year long and use their old holes for roosting at night.  They usually roost alone but on cold winter nights like these “Ma” and “Pa” may roost together to stay warm.

Maybe even in this hole.

 

(photos of woodpecker hole by Kate St. John. photo of pileated woodpecker in Cumberland County, PA by Dick Martin, 2009.)

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Feb 15 2015

Are You Mocking Me?

Published by under Bird Behavior

Two mourning doves (photo by Donna Foyle)

Last week Donna Foyle captured two mourning doves having a silent conversation.

They seemed to be sitting together peacefully but their rumpled feathers indicate something is up.

One of them stretched his right leg and tail.

Two mourning doves (photo by Donna Foyle)

The other one stretched, too.

Two mourning doves (photo by Donna Foyle)

But stretching the tail requires raising a wing and wing-raising is an aggressive move among mourning doves.

Uh oh!  Now they’re both upset.

Two mourning doves (photo by Donna Foyle)

“What are you doing?  Are you mocking me?”

 

(photos by Donna Foyle)

2 responses so far

Feb 14 2015

Happy Valentine’s Day

Pair of mute swans (photo from Wikimedia Commons)

A mute swan pair bows in courtship.

 

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

NOTE:  Mute swans were imported to North America. Though beautiful they are very aggressive and pose a threat to our native waterfowl.

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