Archive for the 'Songbirds' Category

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)

 

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May 06 2014

On A Silk Foundation

Blue-gray gnatcatchers returned to Pennsylvania in April and set up shop immediately. As one of the earliest nesting insectivores they began courtship and site selection right away.

Nest-building is part of blue-gray courtship. Both the male and female build the nest and they make a lot of noise and exaggerated bows when they begin.  Meredith Lombard trained her camera on a nearby nest and filmed this pair’s efforts.

As you can see in the video, the nest is slightly expandable because it’s built on an elastic skeleton of spider webs and tentworm silk.  In the early stages of construction I’ve seen gnatcatchers chatter near decayed fall webworm tents, grab the silk and anchor it to their chosen site.  Later they poke the sides of the nest and stick in new bits of lichen and bark.  They also drag the silk upward to make the nest cup.

All of this activity makes them easy to find and watch.  Cowbirds watch them, too.  On Sunday I saw a pair of gnatcatchers harassing a female cowbird.  I hope they’re able to keep her away from their silky nest.

 

(video by Meredith Lombard)

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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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Mar 13 2014

A Well Developed Sense Of Taste

European starling in Toulouse, France (photo from Wikimedia Commons, CC BY-SA 3.0)

This month the starling flocks will break up when the visitors head north and the locals begin to nest.  In the meantime this informational tidbit may be useful in controlling their roosting habits … or it might not.

On a random search about starlings I found this statement on Wild Birds Unlimited’s Chipper Woods website:  “Starlings have a well developed sense of taste, and are repelled by grape flavoring. Fogging with grape flavoring is an effective and environmentally safe method to discourage these birds from roosting.”

I know that starlings will eat just about anything, including grapes, so I wonder:  What is grape flavoring made of?  Do starlings detect something unnatural and dangerous in it that we cannot?

This starling, photographed in Toulouse, France, knows the answer.  You can tell by his look that he has a well developed sense of taste.

 

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

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Feb 25 2014

Bluebird Fight

Eastern bluebird fight (photo by Karen DeSantis)

We think of eastern bluebirds as gentle birds.  They seem to be poor fighters and often lose battles with house sparrows and starlings, so I was surprised to learn from Karen DeSantis that she witnessed two male eastern bluebirds in a long ferocious fight in late February a few years ago.

Karen described on PABIRDS how the fight began with chasing, then escalated into periodic knock downs and grim combat on the ground.  The males fluttered and rolled over a distance of about 30 feet while the female followed every move, twittering as she watched.  The birds were so oblivious that Karen was able to take photographs of the 15-minute battle.  Karen wrote, “It was the long duration of the fight that interested me the most.”

Though we might not realize it, these battles are consistent with bluebird behavior.

During the winter bluebirds flock in family groups and huddle together to stay warm.  In early spring their togetherness ends as the fathers eject their sons from the group before ‘Mom’ and ‘Dad’ nest again.

But the battle Karen witnessed was not a mild family squabble.  Its intensity indicates the guys were fighting over the lady.

Bluebirds are usually monogamous but about 20% of the young come from extra-pair copulations.  The males seem to know if their ladies’ eyes are wandering and guard their mates more closely if they’ve been messing around.  According to Birds of North America Online, “Experimental evaluations (Gowaty 1980) indicate male-male aggression most likely serves to protect threatened paternity. Males are aggressive to males usually in defense of paternity.”   These battles can be so intense that they end in the crippling or death of one of the birds.

Bluebirds may seem gentle but don’t mess with their mates!  Click on Karen’s photo above to watch a slideshow of the fight.

 

(photos by Karen DeSantis)

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Feb 17 2014

Intrepid Minnesotan

Gray jay in Minnesota (photo by Jessica Botzan)

I’m back in the ‘Burgh with a fond look at my time in Minnesota at the Sax Zim Bog Birding Festival.

Though I never found a great gray owl I saw seven Life Birds(*) and learned a lot about snow and cold.

Cold… was not a problem.  I didn’t have to cope with the worst of this winter in Minnesota but -13F was a typical morning in the bog.  Three to four layers of clothes are important. Toe warmer heat packets inside Sorels are indispensable.  I was never cold.

Snow… is a way of life.  If you’re afraid to drive in snow in Minnesota you’re homebound for half the year.  So you just do it.

Minnesota snowplows are awesome, huge, coordinated.  I arrived during a Winter Weather Advisory (4”-6”) and left during a Winter Storm Warning (5”-7”).  No problem.  All the roads and parking lots are plowed, not to bare pavement but quite passable.  The airport is plowed down to bare pavement.  My flight out of Duluth was delayed only by de-icing.  Check out this video of clearing the runway.

Birds … are intrepid in Minnesota’s winters.  The easiest to find are ravens and black-capped chickadees.  The rarest are Carolina wrens and robins.  The gray jay is the cutest and most intrepid.

Gray jays (Perisoreus canadensis) look like oversized chickadees but have the typical corvid attitude.  They’re bold and curious and willing to eat anything including berries, insects, fungi, other species’ nestlings and small mammals.

Jess Botzan saw this one at Sax Zim Bog during the coldest of the cold weather last month and the bird wasn’t phased by it. Gray jays are so intrepid that they lay eggs in March while temperatures are still below freezing and snow is on the ground.  They don’t even bother to nest again in May and June when the weather is easy.

Like everyone else in Minnesota, the gray jay is intrepid in snow and cold.

 

(photo by Jessica Botzan)

(*) Life Birds seen:  Pine grosbeak, black-billed magpie, boreal chickadee, gray jay, northern hawk owl, black-backed woodpecker, Bohemian waxwing.

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Feb 09 2014

I Can Sound Pretty

Blue jay in winter (photo by Cris Hamilton)

As the days get longer the birds have started to sing again.  Jessica Manack reminded me that one of those songs is quite a surprise.

The blue jay’s typical call is unmistakeable and brash. We usually see him do it because he draws attention to himself when he says “Jay.”

He can also make a wide variety of other sounds, some of which are really odd: Try this link at the Macaulay Library.

But during the courtship season he says KWEE-de-lee, a sound so melodic you think it couldn’t be made by a jay.

When you hear this call, look for the bird and you’ll find him doing rapid deep knee bends, raising and lowering his entire body as he calls.

“I can sound pretty,” says the blue jay.  “I just don’t want you to notice.”

(photo by Cris Hamilton)

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Jan 23 2014

Gregarious

House sparrows in snow in Moscow (photo from Wikimedia Commons)

House sparrows are always gregarious, but more so in winter when they flock together in large numbers.

In the morning and afternoon they disperse to feed, but twice a day — at midday and in the evening — they gather in dense shrubs or evergreens and chatter for an hour or more.  They sound a lot like this.(*)

You might not hear them in today’s cold weather but when you do it’s unmistakable.  They’re in a bush alive with birds … but you can’t see them.  I’ve tried to count them but they fall silent and hide when I approach.  I rarely see even one.

Here’s a flock in a tree, somewhat hidden but easier to see than inside a privet hedge!

House sparrows in a bush in Saskatoon (photo from Wikimedia Commons)

House sparrows love each others’ company so much that, according to the Stokes Guide to Bird Behavior, some travel up to four miles to join the roost.

“Gregarious” works for house sparrows — from Latin gregarius (from grexgreg- ‘a flock’) + -ous (to make it an adjective).

 

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

(*)  The sounds at the link above are similar but not quite the same as winter chatter because they’re from a more intense breeding chase in April.  Listen to this segment from BirdNote for all the sounds house sparrows make.

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Jan 20 2014

Winter Hardy

Published by under Songbirds

Carolina wren in winter (photo by Marcy Cunkelman)

A hundred years ago Carolina wrens (Thryothorus ludovicianus) were a southern bird rarely found in southwestern Pennsylvania but they expanded northward during the 20th century, even into Canada.

Carolina wrens don’t migrate so they have to cope with winter wherever they settle down.  When winters are severe they die off and are rarely seen until new individuals disperse northward to fill the gaps.  This was particularly noticeable after the harsh winter of 1977-78 when it took them ten years to recover their northern haunts.

Since then they’ve done quite well, a success due in part to human changes to the landscape.  Warmer winters, regrown woodlots, and backyard bird feeders all make it easier for Carolina wrens to survive though it wouldn’t have been possible without a change on their part, too.  In 1912 Dr. Frank Chapman considered them to be woodland birds unadaptable to human settings but by 1948 Arthur Bent observed that there was plenty of evidence they’d made the change.  Indeed we see them near our homes every day.

This winter may be a tough challenge for Carolina wrens.  During the polar vortex January 6-7 many birders were concerned that their favorite wrens would perish. We were happily surprised that they came through, sometimes by hiding in our buildings, during the two-day cold snap.

This week will bring another, longer round of arctic cold with temperatures down to 0oF.  Will our wrens make it through this time?

Fill your feeders and cross your fingers.  May our Carolina wrens be winter-hardy, greeting us with their loud calls and songs when the weather warms again.

 

(photo by Marcy Cunkelman)

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Jan 13 2014

Melancholy Tyrant

Published by under Songbirds

Tropical kingbird (photo by barloventomagico, Creative Commons license via Flickr)

Continuing my tropical theme…

The tropical kingbird seems rare to us because his range barely touches southern Arizona and the lower Rio Grande valley, but he’s a very common bird in Central and South America and is often seen near humans because he likes what we do to the landscape — especially our wires.

I became interested in him when I learned his scientific name: Tyrannus melancholicus.  It means “melancholy tyrant.”  Why was he named this way?

Members of the Tyrannus genus are “tyrant” flycatchers because they fearlessly defend their territory, nest and young against much larger predators.  Below, a tropical kingbird attacks a zone-tailed hawk.  Our Tyrannus, the eastern kingbird, does the same to hawks in Pennsylvania.

Tropical kingbird attackes a zone-tailed hawk (photo by barloventomagico, Creative Commons license via Flickr)

Melancholicus, meaning melancholy, is not an obvious choice for such an active bird.  Mourning doves are named for their sad song so I listened to the tropical kingbird’s song in case that’s what gave him his name. Click here to hear.

It doesn’t sound sad to me, but perhaps he’s so-named because he sings this tune in the dark before dawn and stops when the sun rises.

I don’t know…  Do you?

 

(photos of tropical kingbirds in Barlovento, north-central Venezuela, by barloventomagico, Creative Commons license via Flickr) 

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