Archive for the 'Bird Behavior' Category

Jun 09 2014

Eats Tentworms

Published by under Bird Behavior

Yellow-billed Cuckoo eating a tentworm (photo by Robert Greene, Jr)

Who eats tentworms?

Yellow-billed and black-billed cuckoos do.  They’re fond of caterpillars, katydids, grasshoppers, and crickets and are happy to rid your trees of tent caterpillars and gypsy moths.

Bobby Greene captured this yellow-billed cuckoo in the act.

Sadly, our use of pesticides has contributed to rapid declines in both species during the last century.  Yellow-billed cuckoos used to be found across the continent.  They are nearly extirpated from the West.

(photo by Bobby Greene)

 

p.s. We saw a yellow-billed cuckoo at the edge of Chatham Village during the Emerald View BioBlitz.  They’re in the City in wooded habitats.

3 responses so far

May 27 2014

Move Along!

Published by under Bird Behavior

As I mentioned a couple of days ago, songbirds often harass predators during the nesting season.  I’ve seen chickadees harass blue jays and red-winged blackbirds dive-bomb red-tailed hawks but it’s a rare day that any bird takes on a cat.

In these two videos magpies triumph.

Above, a European magpie pushes the envelope with a flea-bitten cat. Fortunately he knows when to fly out of the way.  Notice that the cooing Eurasian collared dove and cheep-ing house sparrow in the background are not participating.  ;)

In the silent video below, two black-billed magpies roust a Maine coon, the largest domestic cat.  The person who posted the video wrote:  “Our cat “Sweetie Pie” is a large Maine Coon cat that often catches birds, but this morning, two Magpies attacked her as she relaxed on the sidewalk. You can see the Magpies actually pecking at her fur!”  It was a minor victory considering how many birds the cat has probably killed.

My cat Emmalina would be disgusted if she could read this statement … but … I think magpies are smarter than cats.

 

p.s. Keep your cats indoors.  I do.

(videos from YouTube)

6 responses so far

May 26 2014

Proof Of Nesting

Ovenbird with nesting material, May 2014 (photo by Marcy Cunkelman)

The fact that it’s carrying dead grass tells us three things about this ovenbird:

  • It’s building a nest nearby,
  • It has a mate,
  • It’s female.

Back in 2004-2009 I participated in the second Pennsylvania Breeding Bird Atlas project in which we watched bird behavior and noted signs of breeding.   We learned that a bird is probably breeding if it’s holding territory, courting, or becoming agitated as we approach.  Its breeding is confirmed if the nest has eggs or young, or if we see an adult carrying food.  (Did you know that most birds don’t bother to carry food unless they’re feeding young? *)   The project was eye-opening because it forced us birders to slow down and observe what the birds are doing.

This ovenbird’s behavior — “Carrying Nest material (CN)” — is Confirmed or Probable nesting depending on the situation.  It’s true that an ovenbird carrying nesting material is a female and she already has a mate, but this is not true of all species.  In some, both sexes build the nest.  In others, such as the Carolina wren, the males build several “test” nests and the females choose.

Among ovenbirds only the female builds the nest and she doesn’t bother to do it unless she has a mate.  She chooses a depression of leaves on the ground and constructs a nest shaped like a beehive oven using grasses, plant fibers, weed stems, leaves, rootlets, mosses and bark.  When completed the nest is so well-hidden that it’s invisible from above.  Click here to see what the nest looks like with eggs inside.

Congratulations to Marcy Cunkelman on finding this ovenbird building a nest.  What a cool photograph.  I have never see this!

(photo by Marcy Cunkelman)

(* There are notable exceptions to the “carrying food” rule… worth learning.)

One response so far

May 25 2014

Little Against Big

During the nesting season small songbirds chase large predators away from their eggs and young.  It’s a topsy-turvy time when the pecking order is reversed.

Sharon Leadbitter saw this in action last week at Allegheny Cemetery when a blue jay repeatedly bopped a red-tailed hawk on the head, trying to drive it away from his territory.

Eventually the blue jay was just too annoying ….

(video by Sharon Leadbitter)

5 responses so far

May 16 2014

How To Build A Robin’s Nest

Mid-May is the height of robin nesting season in Pittsburgh.  The first nestlings have hatched and some are ready to fledge.

On Thursday I saw my first-of-2014 robin fledgling in Schenley Park.  Last month his mother spent 5-7 days building his nest.  This video shows her process in only 8.5 minutes.

While Mr. Robin sings in the background, his mate brings dry grass and drops it into place.  Her project looks sloppy for a while, then she does a cool thing.  She rapidly stamps her feet inside the nest while holding the edges with her wings and tail.  This makes the cup exactly fit her body.  How cool is that!

Halfway through Mr. Robin comes for a brief inspection.  Since he neither builds nor incubates, the nest is of passing interest to him.

When the cup is complete Mrs.Robin lines it with mud, then adds fine bits of dead grass to make the nest soft and lays her eggs.  (The last two steps are not in the video.)

Robins raise two or three broods per year and usually build a new nest for each brood.

What a lot of trips back and forth!

(video on YuoTube by richpin56)

5 responses so far

May 14 2014

Fun Facts About Cigars With Wings

Chimney swift flying in Austin, Texas (photo by Jim McCullough, Creative Commons license, Wikimedia Commons)

The chimney swifts came back to town in April from their winter homes in South America. In this week’s hot weather they’re zooming high above the rooftops eating insects and courting.  If they’d only hold still you could see they look like cigars with wings.  Here are some fun facts about them.

Chimney swifts are “songbirds” but their song is a dry chittering sound, loudest when they’re courting.

They are small. Stretch out your fingers. From the tip of your thumb to the tip of your pinky finger is the wingspan of a chimney swift. If you have big hands, your hand is wider than the bird.

Chimney swifts can’t perch on a horizontal surface. Their legs+feet are shaped like garden claws so they can only cling upright to the inside of a chimney or hollow tree.

True to their name they nest in chimneys, constructing a half-moon cup of twigs glued to the wall with their sticky saliva. To gather sticks they grab dead twigs in flight with their feet and transfer them to their bills to carry home.  I have never seen a chimney swift carrying a twig.  It’s something to look forward to.

Though most mating occurs at the nest, chimney swifts can mate in the air!

The female lays 4-5 eggs which both parents incubate for 19 days.  Even though the chicks are born naked with closed eyes their feet are so well-developed that they can cling to an upright surface on the day after they hatch.

For such a small bird, chimney swifts live an amazingly long time, averaging about 4.6 to 5.5 years.  Some have lived to be 15.

Watch them fly and they’ll inevitably look as if their wings are out of synch, one wing up and the other one down.  This is an illusion caused by their rapid flapping and side-to-side turns.  If you added wings to a cigar it would do the same, but not as gracefully.

 

(photo by Jim McCullough, Creative Commons license on Wikimedia Commons. Click on the image to see the original)

2 responses so far

May 08 2014

Which One Should I Choose?

Trio of brown-headed cowbirds (photo by Dori from Wikimedia Commons)

Brown-headed cowbirds are courting now because their victims are about to nest.  The males sing a bubbly whistling song to attract a favored female.  After she’s chosen a mate, Mrs. Cowbird lays her eggs in the nests of smaller birds whose own eggs and nestlings die while the foster cowbird chick thrives.

In cowbird society nest building and incubation never occur so the pair bond is cemented by courtship songs and postures.  Amazingly, the quality of the male’s song really matters.  That’s how the female decides who to accept and who to ignore.

What happens if a female can’t tell the difference between good and bad songs?  What happens when one lady in the flock doesn’t follow the rules?  Last year scientists learned that one tone-deaf female can upset cowbird society.

Researchers at the University of Pennsylvania led by Sarah Maguire inactivated the song-control centers of some female cowbirds’ brains so they could no longer distinguish between high and low quality songs.  When placed in a mixed-sex flock these ladies reacted to all songs and did not stay with a chosen male for long.

Since male dominance among cowbirds is based on song quality the best guys usually get the best gals.  However, when a tone-deaf female appeared in the flock she listened to all males equally and the minor males got a boost.  The dominant males courted the altered female more vigorously.  The other ladies were left in the cold.

Which guy will she choose?  One tone-deaf female can mess up an entire social structure.

Read more here in PLOS One.

 

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

 

5 responses so far

Apr 25 2014

Smart Black Birds On Camera

Raven on nest at Wellesley College (screenshot from Wellesley College ravencam)

Tired of being outdone by celebrity bald eagles and peregrine falcons, ravens have decided to get into the act.

Last October a pair of common ravens chose Wellesley College as the smart place to be.  Over the winter they scoped out the campus and evaluated future nest sites.  By March it was evident they’d made a wise choice when they built their nest on a high fire escape at the Science Center.  Their platform is enclosed by glass on three sides so they have great views and less wind.

They also have electricity, an Internet connection and night lights — perfect for a webcam — so Pauline and Henry are now celebrities.

Named for the founders of Wellesley College, Pauline and Henry’s choice probably shocked the local raven population.  “What were you thinking!? Humans are unpredictably dangerous!  We never nest that close to them.”  But their unique choice has given them shelter while we get a window on their world.

Pauline laid two eggs in March, one hatched in early April, and now their nestling is growing every day.  Unlike peregrine falcon chicks, raven babies are not cute, fluffy and white.  Instead they’re born naked and awkward with a very large mouth.  When the parents come to the nest “the mouth” opens to show off its red interior.  In the weeks ahead the mouth will stay red but the body will transform into a feathered juvenile raven, one of the smartest birds on earth.

Smartly clothed in black, Pauline and Henry are happy to share their lives with you on camera.  Click here or on the screenshot above to watch them online.

 

(screenshot from the Wellesley College ravencam)

p.s. When ravens blink their nictitating membranes, their eyes look white.  Very cool!

4 responses so far

Apr 23 2014

How Parrots Name Themselves

Published by under Bird Behavior

In case you missed this featured video at the Cornell Lab of Ornithology

Did you know that baby parrots name themselves and that parrots call each other by name? This 2011 video from Cornell Lab is fascinating!

 

Peregrine Fans, there are two connections to your favorite bird.

  • Did you know that peregrines are closely related to parrots and not to hawks?  Click here to learn more.
  • And on the subject of names, how do peregrines get them?  Here’s the story.

 

(video from Cornell Lab of Ornithology)

2 responses so far

Apr 18 2014

Let Them Eat Eggs

This week’s weather was like a yo-yo — summer last weekend, winter mid-week, spring today.  The cold was annoying to us but potentially fatal to purple martins who migrated from Brazil and arrived in western Pennsylvania 2-3 weeks ago.

Purple martins feed exclusively on flying insects but when temperatures stay below 50F or it’s extremely windy, constantly raining, or dense fog, insects don’t fly.  After more than two days of this, purple martins weaken and starve.

Members of the Purple Martin Conservation Association remember the awful purple martin die-off when Hurricane Agnes lingered over western Pennsylvania in August 1972.  It took more than 30 years for purple martins to come back to our area.

In the past purple martin landlords felt helpless as they watched their colonies weaken and die. In the 1990′s Ed Donath trained his martins to eat non-traditional food but that required training time during good weather.  Then during a cold spell in April 2000 Ken Kostka and Andy Troyer figured out an emergency feeding strategy:  toss live crickets in the air.  At first the purple martins idly watched the airborne objects. Then they recognized the crickets as insects and made the connection “flying+insects”=food.  The martins feasted and the colony was saved.

The home video above by Larry Melcher shows how it’s done.  After the martins have learned to recognize the crickets as food, the bugs can be placed on a high tray on the colony and the martins will eat them even though they’re not flying.

Landlords have experimented with other foods.  Years ago Bird Man Mel in Missouri tossed live mealworms so his colony now recognizes mealworms as food and will eat them from the front porch trays (click here for his video).

On Wednesday birders Dick Nugent and Debbie Kalbfleisch visited a purple martin colony in Butler County where the landlord was feeding his colony scrambled eggs!  Here’s a video with the scrambled egg recipe.

Purple martin landlords love their birds.  They start feeding crickets, then let them eat eggs.

(videos from YouTube)

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