Archive for the 'Songbirds' Category

Oct 22 2013

Strong Opening

 

If you’ve ever had a pet starling, you know their beaks are very powerful when opening.  That’s because European starlings have the unusual characteristic that their jaws are strongest in reverse.

It’s a counter-intuitive trait.  Our jaws are strongest when we clamp down.  William Beecher discovered that starlings’ jaw muscles are at their best when they spring open and that their eyes automatically rotate forward for binocular vision as they open their beaks.  This gives them an excellent look at potential prey in the hole they’ve just probed open and probably contributes to their success in winter.

Even as pets, starlings can’t help but probe.  It’s in their blood.  HayleyM‘s pet starling, Lolly, opens her son Aidan’s mouth as a dentist might.  Notice that beak action!

Don’t try this at home!

 

Click here to view the original video and read in the comments how this orphaned starling became a pet.  Also read the important notes in the p.s. below.

(video on YouTube, uploaded January 2011 by HayleyM)

 

p.s. Important notes:

* In North America, European starlings are one of only two wild birds (the other being the house sparrow) that can be kept as pets without a permit.  Both species are listed as invasive.

* In addition to the possibility of people catching disease from birds, HayleyM added this note to the video: “After review by my good friends at Starling Talk (www.starlingtalk.net), I have found out that this is an ill advised practice. Apparently the bacteria in the human mouth can actually make a bird sick.”

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Oct 06 2013

This Is Exciting

Yellow-rumped warbler, October 2013 (photo by Shawn Collins)

They’re here!  The yellow-rumped warblers are back from Canada, on their way to the lower Ohio Valley, the southern U.S., and Central America for the winter.

Yesterday Karyn Delaney and her husband stopped counting at 100 when they found so many yellow-rumps on the Pine Tree Trail at Presque Isle State Park.  Shawn Collins snapped this one in Crawford County.

Like the first snowfall I’m excited to see my first big flock of yellow-rumped warblers in southwestern Pennsylvania.  I haven’t found a flock yet but I think I’ve heard one bird — just one — at Schenley Park.

Unfortunately, just like snow I soon tire of them.  I remember at Magee Marsh last May when my first reaction to seeing yellow-rumped warblers was “Wow!” and within an hour it was “Darn!  Another yellow-rump.”  Their abundance becomes boring.

But I haven’t seen them yet, so for the moment this bird is exciting.

 

(photo by Shawn Collins)

6 responses so far

Oct 02 2013

The Most Pugnacious Woodpecker

Juvenile red-headed woodpecker attacks an adult (photo by Chris Saladin)

Watch out!

Last week Chris Saladin captured these action shots of two red-headed woodpeckers in a protracted fight at Sandy Ridge Reservation.  The immature woodpecker, still clad in gray, seems to have the upper hand.  What’s the deal here?  Why are they fighting?

All woodpeckers chase to maintain their territories but red-headed woodpeckers take fighting to an extreme.  During the breeding season they’re aggressive to everyone, especially the cavity-nesters.  They persecute northern flickers, red-bellied and downy woodpeckers.  If a starling dares to take a red-headed’s nest hole the woodpecker fights — and wins.  Even the pileated woodpecker defers to this bird.

Red-headed woodpeckers are especially aggressive toward each other and are solitary in winter because they fight so much.  Each one establishes a winter territory where he gathers and stores acorns for his personal use.  All other red-heads — male, female and immature — must stay away!

Perhaps the immature showed up on migration and is hoping to claim the Sandy Ridge wetland.  The adult is having none of it!

Above, he makes the bark fly as he bounces off the dead tree.  Below, he’s quick to get out of the way as the immature zooms in!

Juvenile red-headed woodpecker chases adult (photo by Chris Saladin)

And here they’re airborne in foot-to-foot combat!

Juvenile and adult Red-headed woodpeckers fighting (photo by Chris Saladin)

Apparently they can’t stand the sight of each other.

Will they ever stop?  Finally the immature pauses so we can see him at rest.

Juvenile red-headed woodpecker (photo by Chris Saladin)

A most pugnacious species!

 

(photos by Chris Saladin)

p.s. Click here to see what an adult red-headed woodpecker looks like when he’s not in battle.

6 responses so far

Oct 01 2013

Starling Story Problem

European starlings (photo by Bobby Greene)

When I was in grade school I hated Story Problems in math class — those word problems without formulas, just a bunch of facts to solve.

But life is full of stories.  I overcame my disgust, learned how to turn word problems into formulas, and became a math major.  Thus when I wrote about starling flocks last Friday I began to wonder…

How did the starling population increase from 100 birds released in Central Park in 1891 to 200 million (or more) in 2013?

Using information on their breeding habits and survival rate, I did some crude mathematics and came up with an answer.  First, the facts:

  • Starlings north of the 48th parallel produce only one brood per year, the rest produce two.  (To give you an idea of this location, the western U.S.-Canada border is at the 49th parallel.)
  • Female starlings typically lay 5 eggs per nest.
  • 50% – 80% of the eggs survive to the fledgling stage.
  • 20% of the fledglings survive to adulthood.
  • 60% of the adults survive each year.

(Warning!  If math makes your head spin, now’s the time to skip to the end.)

If we started with 100 starlings in Pittsburgh this spring, how many starlings would we have next spring?   To make it simple I made some big assumptions and did a lot of rounding.

  • 100 starlings = 50 nesting pairs
  • 50 pairs * 2 nests per year * 5 eggs per nest = 500 eggs this year
  • 50% to 80% of the eggs will fledge.  I used 65% * 500 eggs = 325 juvenile starlings in August.  I rounded this down to 300.
  • 100 adults + 300 juveniles = 400 starlings in August.   This is why we see so many starlings in the fall — and this doesn’t even include the migrants.
  • 60% of the adults survive to the next spring = 60% * 100 = 60 adults in March
  • 20% of the juvies survive the winter = 20% * 300 = 60 former juveniles in March
  • 60 adults + 60 of last year’s juveniles = 120 starlings in March

If I’m right (but I’m not) our starling population increases 400% in August, then winter trims it to an annual increase of 20% by March.

But 20% is too high.  Sixteen pairs survived from the 100 birds released in Central Park in 1891.  If their increase had been uniform it would resemble compound interest over 120 years (1891 to 2011) of about 14%.

(If you skipped the math, join me here.)

Interestingly, scientists estimated that the starling population boom in the western U.S. in the 1970′s was 16% per year, so I got close.

Fortunately the starling population seems to have stabilized so their annual increase is now — perhaps — zero.

How’s that for a story problem?

 

(photo by Bobby Greene)

3 responses so far

Sep 11 2013

On The Move

Published by under Migration,Songbirds

Swainson's thrush (photo by Shawn Collins)

Last night in Bath, Maine I heard thrushes migrating in the dark.  As they fly they make short contact calls to keep the flock together. Among the calls, I was able to identify two species.

The first call was plentiful and sounded like the single note of a spring peeper.  Those were Swainson’s thrushes (above).  Click here to hear the peep sound at the beginning of the recording.

The second sound was less frequent.  There were fewer of this species, their call note lasted longer and descended roughly.  By listening at the Macaulay Library online I determined they were gray-cheeked thrushes (below).  Click here to hear.

Gray-cheeked thrush (photo by Shawn Collins)

 

Last night the birds were on the move while the weather was good.  Today will be hot.  Tonight will be stormy.

 

(photos by Shawn Collins)

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Sep 10 2013

Sappy Nests

RBNU_9697353680_70396a3c93_rsz_shawncollinsRed-breasted nuthatch (photo by Shawn Collins)

Red-breasted nuthatches are the first bird I hear every morning in Maine.  What are they up to?

Right now they’re spending a lot of time caching conifer seeds to last them through the winter.  All summer long they ate arboreal arthropods (insects in trees) but now they’re switching to seeds, hiding them under bark or in sapsucker holes, covering the opening with lichen or plant matter. If there aren’t enough cones they move south, as so many did last winter.

Though they depend on cone-bearing trees for food, red-breasted nuthatches prefer to nest in dead or dying birches or aspens whose trunk is softened by disease or rot.  They often pick a birch with a broken top.  The lady digs the nest hole while her mate watches and brings her food.  She throws sawdust out of the hole leaving a telltale pile below the nest.  I’ve never seen this because I’m never in Maine during nesting season.

If I came here in the spring — or spent time watching the few red-breasted nuthatches who nest near Pittsburgh — I would see this amazing nesting habit:  To protect their eggs and nestlings they collect pine sap on the tips of their bills or on a little piece of bark, then smear it around the opening of the nest.  The male smears sap on the outside, the female smears it on the inside.  Experiments have shown this sticky mess keeps away both predators and competitors.

Adult nuthatches are very skillful at zooming straight into the nest without touching the sides — those who don’t are eliminated from the gene pool — so how do the nestlings fledge without getting stuck?  According to Birds of North America Online, parent nuthatches place small clumps of fur on the sticky inner nest rim on the day of fledging.

They make a stick-free launch zone for the kids to leave the sappy nest.

(photo by Shawn Collins)

3 responses so far

Aug 06 2013

I Will Sing With You

Nightingale singing in Berlin ()photo by J. Dietrich via Wikimedia Commons

Yesterday while on my way to somewhere else , I discovered a blog called Goldbird Variations that began when the author started playing music for birds.

Years ago Lisa Rest of Chicago took up the piano again and often played with her window open.  One day a mourning dove flew to the windowsill and sang along.  She didn’t understand what it was doing until later, wanting to share her music with an audience, she rediscovered that the birds were listening outside her window and singing as she played.

Soon she began intentionally playing music for birds, recording their duets and writing about her encounters.  Now she’s hooked on birds and blogging.  I know how that is!

Lisa has perfect pitch and can tell that the birds do too.  Listen to a cardinal sing with her in this post that explains why birds are attracted to music.

Which leads to the nightingale above…

Lisa points out she’s not the only one to play music for birds.   In May 1927 the BBC recorded Beatrice Harrison playing Londonderry Air on her cello in her garden in Surrey as a nightingale sang along.  The bird waits for her phrases and blends in at appropriate times.  Amazing!  Click here to download and play the mp3 recording from the Music And Nature radio program.

I have neither perfect pitch nor musical skill but I’ve encountered birds’ interest in music when I whistle while I hike.  I’m particularly fond of Bach and Beethoven and since I don’t sing well I whistle my favorite tunes.

Their favorite of my repertoire seems to be the second movement of Beethoven’s 6th Symphony, Szene am Bach (Scene at the brook) from his Pastoral Symphony.

Of course the birds like that one!

 

(photo of a nightingale singing in Berlin.  Click on the image to see the original on Wikimedia Commons.  This post was inspired by the Goldbird Variations)

5 responses so far

Jul 31 2013

Mysterious Disappearance

House sparrow (photo by David Lofink via Wikimedia Commons)

If you live in North America this fact is amazing:  House sparrows are an endangered species in Britain.

I learned this when I read John Metcalfe’s article called Making Cities More Bird Friendly With Nesting Bricks.  In it he describes a new brick specially designed by Aaron Dunkerton and manufactured in England to provide habitat for nesting house sparrows.  Before mortar is applied it looks like this.  (Click on the bricks to read about them.)

Bird brick by Aaron Dunkerton (image from Aaron Dunkerton's website)

House sparrows are the most widely distributed wild bird on earth.  Why are they so endangered in the U.K. that people invent ways to help them?  Here’s what I found out.

Since 1977 house sparrows have declined by 71% in Britain.  In some locations they are nearly extirpated.  London’s Kensington Park had 2,603 house sparrows in 1925.  By 2000 there were only 18.

Despite many studies a single cause has not been found and no other urban/suburban bird has experienced a similar decline.

In 2005 Kate E. Vincent published a house sparrow population study.  In 2009 Lorna Margaret Shaw investigated the role of neighborhood socio-economic status in house sparrow abundance.  These studies found:

  • The greatest house sparrow declines occurred where nestlings starved within a week of hatching or had low fledging weight, both due to lack of insect prey.  The best success occurred where they ate plenty of aphids or spiders.  (Aphids come up again!)
  • Because house sparrows nest in holes in buildings, they did well in neighborhoods built before 1919, in neighborhoods where soffitt and fascia were made of wood, and in distressed neighborhoods where the buildings needed repairs.  They avoided neighborhoods built after 1985 because of new construction standards and lack of deterioration.  That’s why Aaron Dunkerton invented the bird brick for new homes.
  • House sparrows did poorly in tidy neighborhoods with lots of paving.  Over the years Britons have paved their front yards and removed trees and shrubs so they can park their cars.  This has reduced house sparrow habitat.
  • All habitat was not equal.  House sparrows preferred deciduous plants and the insects associated with them.
  • House sparrows did not use ornamentals or evergreens.  This lead to a headline that Leylandii hedges were to blame for the house sparrow decline.  (A fascinating topic…more on that tomorrow.)

With so many factors in play there’s no simple answer to the house sparrow’s mysterious disappearance.  In the meantime they continue to decline and Britons miss them terribly.

If it would work I’d package some of ours and send them to England.  We have a house sparrow surplus right now.

 

(photo of a house sparrow in California from Wikimedia Commons. Nesting bricks by Aaron Dunkerton.  Click on the images to see their originals.)

7 responses so far

Jul 20 2013

Mr. Gorgeous

Indigo Bunting, male (photo by Shawn Collins)

Beautiful and blue, a male indigo bunting poses for a photograph.

Gorgeous!

 

(photo by Shawn Collins)

One response so far

Jul 08 2013

African Starlings Invent New Colors

Greater blue-eared glossy-starling in South Africa (photo by Dick Daniels on Wikimedia Commons)

African starlings evolve color faster than any other bird — 10 times faster than their ancestors and modern relatives according to a new study from the University of Akron.

Like other Sturnidae these birds had iridescent qualities, but after they made it to sub-Saharan Africa 17 million years ago their colors went wild.   The cells that give their feathers iridescence are called melanosomes.  Instead of the usual simple rod-like forms, glossy starlings (Lamprotornis) developed hollow rods, solid flattened rods, and hollow flattened rods.  Though these divergent melanosomes are sometimes found in other birds, glossy starlings can have all the variations in one species.  This produced an explosion of new colors.

At the University of Akron Rafael Maia studied microscopic feather structures and used spectral color analysis and evolutionary modelling to figure out how these starlings evolved four types of melanosomes and 19+ species.   It happened very fast.

Their social structure helped.  For glossy starlings, color confers high rank in both sexes so the most colorful birds are the most successful breeders.  Intense social pressure selected for better and better colors.

The results are gorgeous.  Above, a greater blue-eared starling (Lamprotornis chalybaeus) shows off his teal and blue back. Below, a lesser blue-eared starling (Lamprotornis chloropterus) displays five colors even though he’s molting.

Lesser blue-eared starling (photo by Sumeet Moghe via Wikimedia Commons)

 

Read more about the study here in Science Daily.

 

(photos of a greater blue-eared and lesser blue-eared starling from Wikimedia Commons. Click on the images to see the originals)

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