Archive for the 'Musings & News' Category

Aug 27 2014

Birds *Are* Dinosaurs

Published by under Musings & News

Four-winged dinosaur, Changyuraptor yangi, discovered in China (illustration by Stephanie Abramowicz, NHM)

(illustration by Stephanie Abramowicz, NHM)

News broke in mid-July of a newly discovered dinosaur with four wings and a very long tail.  As a member of the Microraptoria clade, Changyuraptor yangi is unusual.

Microraptors had been characterized as 2.5 – 3 feet long weighing up to 2.2. pounds, but this one broke the mold.  Changyuraptor is four feet long with 30% of its length made up of foot-long feathers at the end of its tail.  The animal is “four-winged” because it has long feathers on all four limbs.  And it was heavy — probably 9 pounds — which is four to six times heavier than a peregrine falcon, more similar in weight to a male bald eagle.

Changyuraptor’s long tail showed that this non-avian dinosaur had good flight control.  If you watch a big (modern) bird coming in for a landing you’ll see it slow its air speed by pushing down its tail and holding its head high.  The July report in Nature Communications said this dino could do that too.  Unfortunately the feathers on the raptors forewings (arms) were not well preserved, so scientists can’t tell if it could take off from the ground or only glide from trees.

Though he could fly Changyuraptor yangi is non-avian in other respects.  He had teeth instead of a beak and bones in his tail.  But he was clearly a forerunner to birds.  If you ask someone who knows a lot about dinosaurs what he thinks of birds you get a very cool answer.

In a video from the Syndey Morning Herald (click on the illustration to see the video) science columnist Peter Spinks interviews two paleontologists, one in the studio and one on the phone.  He asks both of them, “Does this clinch the deal for you that dinosaurs were the precursors of birds?”

Both answer that the deal was clinched for them long ago.  And then the second paleontologist, Mikael Siversson, adds, ““Not only are birds descended from dinosaurs, but in fact birds are dinosaurs. They are highly specialized surviving dinosaurs.”

Woo hoo!

 

Read more here at Science Matters.

(illustration of Changyuraptor yangi by Stephanie Abramowicz, Natural History Museum of Los Angeles County)

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Jul 29 2014

Even Less Water Than We Thought

Colorado River water loss as seen at Lake Mead, Nevada (photo from US Bureau of Reclamation)

Rainfall in Pittsburgh is normal this year but out West they’re in their 14th year of drought with no end in sight.  This is starkly obvious at Lake Mead near Las Vegas where the water level has dropped 138 feet, leaving a “bathtub ring” of mineral deposits.

Three western states depend on Lake Mead for water and on its dam for electricity.  Since last October 4.2 million acre feet came into the lake but 7.9 million was withdrawn.  The lake has dropped 30 feet in the past five months alone.  As the water drops so does Hoover Dam’s generating capacity, putting the electric supply at risk too.

You’d think this problem could be fixed by controlling surface water consumption but it goes much deeper than that.

Back in January, I wrote about NASA’s GRACE satellite pair that measures groundwater from outer space (click here to read how it works).  Using nine years of GRACE data from the Colorado River Basin, University of California Irvine and NASA scientists made an alarming discovery.  From December 2004 to November 2013 the watershed lost 53 million acre-feet of water, an amount almost twice the size of Lake Mead.  More than 75% of that loss was from groundwater.  No one knows how much water is underground but it’s going fast.

When wells deplete groundwater, there are significant downstream consequences.  A 2012 study by Stanford Woods Institute found that overpumping can make the surface run dry.  Though surface water is carefully managed in the West, groundwater use is often poorly documented and barely managed — if at all.

Water loss at this scale affects every living thing.  Near Las Vegas the wetlands along Lake Mead are gone and so are the birds and animals that depended on them.

If the loss continues at this rate, humans may have to leave Las Vegas, too.

 

Read more about this study in Science Daily.

(photo of Lake Mead by U.S. Bureau of Reclamation)

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May 13 2014

A Last Look?

Olive-sided flycatcher (photo by Dominic Sherony via Wikimedia Commons)

On Sunday afternoon I saw an olive-sided flycatcher above the Sand Dunes Trail at Oak Openings Preserve, Swanton, Ohio.  I mention these specifics because he was only the second olive-sided flycatcher I’ve ever seen.  The first was 11 years ago at Raccoon Creek State Park on May 18, 2003.

Olive-sided flycatchers were always uncommon and now are increasingly rare.   In the past 40 years they’ve declined 3.3% per year, especially in western North America.  Where there used to be 100 individuals there are only 27 now.  They used to nest in Pennsylvania but no more.

Though he isn’t a flashy color he’s the peregrine falcon of flycatchers.  Perched high on a dead snag he scans the air for large flying insects, dives to catch them, and chases them down if they try to escape.  This bird is fast!   I watched him chase down bees or wasps, return to the perch and swallow each catch in a single gulp.  He rarely missed.  Then, just like a bird of prey, he ejected a pellet.

Olive-sided flycatchers breed at coniferous and boreal forest edges in the western U.S. and Canada and spend the winter in northwestern South America.  They happen to prefer burned or logged areas because the openings make for better flycatching.  The bird I found was in a location that had burned several years ago.

Pesticides, loss of bees and wasps, and habitat loss in North and South America have all contributed to the olive-sided flycatcher’s decline.  A reintroduction program like the one that restored the peregrine falcon can’t save this bird.   Instead we have to cooperate to preserve large tracts of his habitat.  Unfortunately, human cooperation on this scale is notoriously difficult to achieve.

This was my second look at an olive-sided flycatcher.  Will it be my last?

 

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

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Feb 10 2014

Fresh Water At Risk

Published by under Musings & News

Aqueduct mapping tool screen shot at World Resources Institute

In the U.S. we tend to think that oil is the most precious and contested substance on earth because we hear about it in the media every day:  oil exploration, spills, oil prices and wars.  But if you think competition for oil is bad, water is worse.  Oil is a luxury, water is a basic necessity and clean fresh water is getting harder to find.

Last month the World Resources Institute (WRI) published Aqueduct, an interactive tool that measures and maps water risk.  From the maps I learned that water woes come in many flavors.

Some are naturally caused:   (This is not an exhaustive list!)

Others have man-made origins:

Water is very complicated,” says WRI.

Try their Aqueduct interactive tool to see where water is at risk.  You may be surprised at what you find in Wisconsin, Michigan and Cape Cod.

 

(screenshot of the Aqueduct mapping tool at World Resources Institute. Click on the image to use the tool)

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Feb 06 2014

Clean Your Bird Feeders

Published by under Musings & News

House finches in Phoenix, Arizona (photo by Kevin McGraw, Arizona State University)

In the depths of a bitter winter it’s a challenge to wade through ice and snow to refill the feeders and even more challenging to pull in those feeders and clean them.  Every day I put it off.  This message is for all of us who’ve been procrastinating.

A new study published this week in PLOS One has found a direct link between urbanization and avian infections.  The denser the human population, the sicker the birds.

Mathieu Giraudeau, Melanie Mousel, Stevan Earl, and Kevin McGraw studied canarypox and Coccidian infections in male house finches (Haemorhous mexicanus) in the Phoenix, Arizona metro area.  Like chicken pox, canarypox forms blisters on the skin.  Coccidiosis is caused by parasites in the intestinal tract, spread by infected feces or ingestion of infected tissue.  During the study, house finches with coccidiosis were found to be fatter but unable to absorb the nutrients they ate.

At each site where they trapped and diagnosed house finches, the researchers also noted the land use patterns and habitat.  Then they looked for correlations and found:  The denser the human population and the less natural the habitat, the higher the number and intensity of infections in the birds.

Why?

According to Science Daily: “Much like the spread of human disease in populated areas, urban centers can foster increases in multiple disease types in wild animals,” said Kevin McGraw, senior author of the study. “We are now investigating the mechanism underlying this observation.”

And from the PLOS One article: “Humans may facilitate infections in these birds via bird feeders (i.e. horizontal disease transmission due to unsanitary surfaces and/or elevations in host population densities) and/or via elevations in other forms of physiological stress (e.g. corticosterone, nutritional).”

Interestingly this photo from the study may hold a visual clue to the health of these two birds.  Male house finches should have red faces like the bird on the left.  Those with yellow have not absorbed enough carotene to produce red feathers.  Perhaps the yellow-faced bird has coccidiosis.

Bottom line:  Clean your bird feeders.

Read more here in Science Daily or the research article in PLOS One.

 

p.s. Click here for information on how to clean your bird feeders.

(photo by Kevin McGraw, Arizona State University)

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Jan 05 2014

Two Resins For Tomorrow

Published by under Musings & News,Trees

Frankincense from Yemen (photo from Wikimedia Commons)

Back in December when I wrote about amber, I learned about other tree resins important to humans.  Two of them are celebrated tomorrow on the traditional anniversary of the visit of the Magi who brought gold, frankincense and myrrh to the infant Jesus.

Frankincense, native to the Arabian peninsula and the Horn of Africa, is a hardened resin used in religious ceremonies around the world. It’s been traded for at least 5,000 years, burned as incense or steamed to release its essential oils.

The resin is produced by slashing the bark of trees in the Boswellia genus as often as two to three times a year.  Some say that Boswellia sacra produces the best.  Ironically frankincense trees are declining because agricultural pressure is clearing the land and the remaining trees can’t produce viable seeds if they’re slashed too often.

Frankincense tree, Boswellia sacra (photo from Wikimedia Commons)

 

Myrrh is the resin of thorny trees in the Commiphora genus, valued for its religious and medicinal uses.  Just like frankincense it’s produced by slashing the tree’s bark to make it ooze sap.

Myrrh (photo from Wikimedia Commons)

Commiphora myrrha is one of the species favored for myrrh and because it is native to Yemen, Somalia, Eritrea, and eastern Ethiopia Biblical scholars say that the wise man who gave that gift came from one of those countries.

Commiphora myrrha produces myrrh (image from Wikimedia Commons)

 

Tomorrow these two resins will be in the limelight, though frankincense and myrrh are used throughout the year.

 

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

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Jan 02 2014

Beautiful Birds, 2013

What were your favorite birds of 2013?

If you’re from western Pennsylvania or northeastern Ohio, Steve Gosser’s six-minute video of favorites is likely to include a few of your own.

From the very public fight between a red-tailed hawk and a bald eagle to the elusive Virginia rail, Steve photographed all of them within a two-hour drive of Pittsburgh.

Beautiful!

(photos and video by Steve Gosser)

 

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Dec 23 2013

I Am Not Starving

Snowy owl in Wattsburg, PA (photo by Shawn Collins)

Joe Monahan of Boone County, Iowa generated a heated discussion on PABIRDS last week when he urged folks to save snowy owls by feeding them store-bought mice.  According to Joe the owls are starving: “The dead owls found here that were necropsied were found to be emaciated. Which is why I decided to start feeding the one remaining in our area.”

His idea raised ethical issues but Joe’s argument was that, based on those found dead, snowy owls are starving and ought to be fed.  The core of the discussion came down to: Were the dead owls evidence of a starving population?  Will feeding help or hurt?

Deciding the leading cause of death of a population — and what to do to help that population — based on those “found dead” is quite misleading.   If you visited Moore, Oklahoma on May 11 the majority of people found dead were killed by a tornado.  If we acted on that very real but skewed statistic we would move people out of Oklahoma because it’s a state known to have many tornadoes. However, the real leading causes of death in Oklahoma are heart disease and cancer, as elsewhere in the US.  Moving people away from Tornado Alley would not help and could hurt — upsetting some so much that they’d die prematurely (the autopsy would say it was heart disease).

Snowy owl studies by Paul Kerlinger, Norman Smith and colleagues show that as a population, wintering snowies are not starving at all.  Kerlinger’s study says: “Trauma-induced mortality was the cause of death in 64% of all cases, and starvation was implicated in just 14%, a figure the authors felt was likely inflated by several factors. Almost half of all snowy owls examined had moderate to heavy fat, and many of those lacking fat had suffered massive injuries.”   (Note that a bird that’s suffered massive injury starves because it cannot hunt.)  And, “of the 20 snowy owls Norman Smith satellite-tagged at Logan Airport, only four died – one from a plane strike and three from gunshot wounds.”  (People do hunt snowies up north.)

Will feeding help or hurt the birds?  Joe described his feeding method:  Holding a live mouse by the tail he would wait for the owl to fly toward him, then he toss the mouse when the owl was within 100 yards. Or he tossed a live mouse on a gravel road for the owl to retrieve.

Since the real leading cause of death in snowy owls is trauma, Joe’s well intentioned effort will probably backfire.  The owls will learn to trust humans and roads and may die prematurely, hit by a car or a bullet.

For everyone’s well being, learn more before you act.

“I am not starving,” says the snowy owl.

 

(photo by Shawn Collins)

p.s.  A big new snowy owl study has just been launched. Click here for details.

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Dec 19 2013

Same But Different

Steller's jay at Sandia Peak, New Mexico (photo by Steve Valasek)

Recent photos by Steve Valasek in New Mexico reminded me that western birds are often very similar to their eastern cousins.  Unlike the ecologically equivalent birds who live on different continents but have similar habitat requirements, these live on the same continent but have different habitat requirements.

Here are two western birds that fit the bill.

This Steller’s jay perched on a feeder in the Sandia Mountains is recognizably similar to our blue jay but he lives in evergreen forests in the mountainous West.  The blue jay prefers oak forests because he loves acorns.  Both jays like to visit bird feeders.

Below, the mountain chickadee also lives in dry evergreen forests in the Western mountains. He looks like a black-capped chickadee except for his white eyebrows.  The black-capped chickadee is far less picky about habitat and can be found in deciduous and evergreen forests, residential neighborhoods, weedy fields and cattail marshes.  Because of this the black-capped has a wider range.

Mountain chickadee, Sandia Mountains, New Mexico (photo by Steve Valasek)

 

And finally, a seed-eating generalist, this dark-eyed junco shows how different he looks in the West.  He’s different but the same.

Dark-eyed Junco, Embudito Canyon, New Mexico (photo by Steve Valasek)

Juncos breed in northern or mountain forests but can be found in a wide variety of habitats in winter.

When I first started birding juncos like this one were listed as a separate species, the Oregon junco.  Since then evidence has shown that the slate-colored junco of the East, the Oregon junco of the West, and the “white-winged” and “gray-headed” juncos are different races of the same species, now called the dark-eyed junco.

There is still much scientific discussion about the “lumping” of the junco.  Given enough time and isolation eastern and western juncos could become separate species and settle the question for us.

 

(photos by Steve Valasek)

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Dec 12 2013

Ancient Air

Published by under Musings & News

Spider and ant fossilized in amber (photo from WIkimedia Commons)

Amber is a rock that began as tree resin.  When it was resin it collected pollen, flecks of dirt, plants, small creatures, and other debris as it flowed from the tree. The amber above contains a spider, air bubbles, dirt and an ant, all preserved when the resin hardened.

Scientists are fascinated by amber because everything inside it is as old as the rock.  This year an international team led by Ralf Tappert of the University of Innsbruck analyzed carbon-12 and carbon-13 in present-day tree resin and amber dating all the way back to the Triassic period.  They chose amber for their chemical analysis because, as Tappert explains, “Compared to other organic matter, amber has the advantage that it remains chemically and isotopically almost unchanged over long periods of geological time.”

From 538 samples they calculated the concentration of oxygen in the atmosphere for 220 million years of the Earth’s history.  Surprisingly, they learned that the concentration in the early Cretaceous period was only 10-15% compared to 21% oxygen today.  The dinosaurs had less oxygen to breathe than we do!

This finding tossed out at least one theory about the dinosaurs, namely that their size was possible because they had so much more oxygen to breathe.  Oops!  They had less.

Click here to read more about the study at ABC Science (Australia).

Ancient air tells the tale.

 

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

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