Archive for the 'Songbirds' Category

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.)

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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)

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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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Jun 20 2013

Blackbird Singing In The Dead of Night?

Published by under Songbirds

The lyrics of the Beatles’ Blackbird song used to puzzle to me. What blackbird sings in the dead of night?  In eastern North America I didn’t know of any blackbirds that did that.

My worldview was too small.  North American blackbirds are icterids: Brewer’s, red-winged, rusty, tri-colored and yellow-headed.  In England common blackbirds are thrushes, a single species Turdus merula similar to the American robin.

The common blackbird’s song is complex, varied and beautiful.   His syrinx allows him to sing two songs simultaneously and even harmonize with himself.  In the video above he starts out loudly on a perch, then drops to the ground and whisper-sings just like a robin.  Like our robins he also sings at night.

Common blackbirds rival wood thrushes for virtuosity and grace notes.  For a longer sample of their song, dip into this 9 minute audio track on YouTube.

The Beatles recorded Blackbird 45 years ago this month.  Though it’s not a song about birds, a blackbird sings on the soundtrack.  Click here to learn what the song is really about.

(videos from YouTube)

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May 05 2013

On Erie’s Southern Shore

Published by under Migration,Songbirds

Cape May warbler (photo by Bobby Greene)

Cape May warblers are some of the many wonderful birds at Magee Marsh, Ohio this year.

Other highlights on the south shore of Lake Erie include:

  • An eye level look at a cerulean warbler,
  • Discovering that a brown lump in a field was an American golden-plover when he turned around,
  • Finding two soras in the reeds … and then they mated,
  • Seeing a great horned owl nestling with pretty face feathers,
  • And watching a sora cross the road. He made himself into a ball so he looked like a very slow, round muskrat without a tail (was this camouflage?) and risked his life by walking slowly in front of traffic.  Fortunately all the drivers were birders and we stopped to stare and spare his life.

Glad to be here!

(photo by Bobby Greene)

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Apr 16 2013

Tapping At My Chamber Door

Robin fighting his reflection (photo by Charlie Hickey)

On April 8 Charlie Hickey and his wife Carole heard a tapping at their front door but no one was there.

When the sound persisted they discovered a robin was attacking his own reflection in the door’s kickplate.

Convinced he was facing a rival, the robin would not give up. Here he tries to stare down that other bird.
Robin staring down his reflection (photo by Charlie Hickey)

 

And here he threatens him with the puff display.  Look at the expression on his face!

Robin threatening his own reflection (photo by Charlie Hickey)

 

Most birds don’t understand mirrors but I can understand why this bird is fooled.  His reflection is that sharp!

When Charlie posted these photos on his Flickr account he alluded to Edgar Allen Poe’s Raven and wrote, “In spite of Carole opening the door and the trash pickup, [the robin] kept returning until Carole covered the kickplate with the door mat.”

What a relief when the door mat went up!

 

(photos by Charlie Hickey)

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Mar 29 2013

When Will The Robins Nest?

American robin on nest (photo by William Majoros on Wikimiedia Commons)

Spring is moving north and so are the robins.  This week a big wave arrived after Monday’s snow.  Now that they’re here, how soon will they nest?

Robins nest later the further north you go.  In 1974 Frances James and Hank Shugart were curious about the conditions that governed their nesting times throughout the U.S.  Using climate data and Cornell nest watch information from 8,544 robins’ nests they developed a model that predicted when robins would nest in a particular region.(*)

The model shows that robins cue on weather.  Hatching is timed to occur when local humidity is 50% and temperatures are between 45 and 65 degrees Fahrenheit.  By April 23, Pittsburgh’s highs and lows are exactly in that range so our birds are getting ready.  Here’s what they’re up to:

  • Robins spend 5-7 days building their first nest of the season. 
  • Egg laying begins 3-4 days after first nest completion.
  • Eggs are laid one per day for a clutch of 3-4 eggs.
  • Incubation lasts 12-14 days.

From nest building to hatching, the first nest takes 26 days. (Subsequent nests take less time.)

Our robins should be nest building right now except for one thing:  Do they have enough mud to begin construction?   Has the mud been frozen?

Watch the robins in your neighborhood to see what stage they’re in.   Join Cornell Lab’s Nest Watch program and your data can become the basis for studies like James’ and Shugart’s that broaden our knowledge of birds.

 

(Credits: photo by William Majoros on Wikimedia Commons.  Click on the image to see the original.
Today’s Tenth Page is inspired by page 260 of Ornithology by Frank B. Gill, portions of which are quoted(*) in this article.
)

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Mar 18 2013

The Lady Is Bald?

Published by under Songbirds

Female red-bellied woodpecker (photo by Dan Dugan)

Here’s an unusual view of a female red-bellied woodpecker.

Normally we see her from the side and notice her black-and-white back and overall paleness.  But from the top, and in bluish light, the gap in her red helmet almost makes her look bald.

Here’s her male counterpart.  No doubt about his red head!

Male red-bellied woodpecker (photo by Dan Dugan)

 

Watch for their mating ritual this month as they engage in “mutual tapping” on the tree they’ve chosen for their nest.

Thanks to Dan Dugan for this unusual look at a common bird.

 

(photos by Dan Dugan)

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Mar 09 2013

Portrait of a Mockingbird

Published by under Songbirds

Northern Mockingbird (photo by Cris Hamilton)

A northern mockingbird shows off his attitude.

(photo by Cris Hamilton)

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Mar 04 2013

Thrashing It Out

Published by under Songbirds,Travel

California thrasher (photo by Alan Vernon from Wikimedia Commons)

We’re starved for thrashers in Pittsburgh right now.  Of the eight species in North America only one, the brown thrasher, occurs in the eastern U.S. and he’s away on migration.  All the rest are western or southwestern birds, several of which occur in California.

This one has “California” in his name.  He doesn’t migrate — in fact he hardly moves away from his birthplace — so if you want to see him you have to be in California or northern Mexico.

The California thrasher loves dense desert chapparel but is sometimes found in scrubby or suburban habitat where he encounters a bird whose habits are quite similar.

Northern mockingbirds eat the same food and forage in the same way as California thrashers.  Both are highly territorial so when a mockingbird moves into a thrasher’s territory constant warfare ensues.

Imagine the two contestants hopping and lunging.

Hey, Mr. Mockingbird, watch out for that beak!

Fortunately for northern mockingbirds, few of them like dense chaparral so these species are usually in separate places.

Good for the thrasher too.  What a waste of energy to be constantly thrashing it out!

 

(photo by Alan Vernon from Wikimedia Commons. Click on the image to see its original)

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