This year’s remembrance of the passenger pigeon is, for me, inextricably linked to Christopher Columbus.

Last year I read a book that generated that association.  1491: New Revelations of the Americas Before Columbus describes what North America was like before and after Columbus’ arrival.

Before Columbus, the human population in the Americas was larger than Europe’s and the landscape, animals and birds were balanced by the pressure of so many people.  Europeans arrived and accidentally left behind pigs carrying human disease.  Native Americans, who had no immunity to European disease, encountered the free-range pigs and spread the plagues through human contact.

The Western Hemisphere suddenly lost 95% of its human population in only 150 years.  Remove the keystone species and you get some pretty weird results.  European settlers didn’t see the transformation so they thought what they found was normal including the endless forest, huge bison herds and billions of passenger pigeons.

So I wonder …

If Native Americans had not died off, would passenger pigeons have boomed at all?

If there hadn’t been so many passenger pigeons, would we have hunted them to extinction?

What if?

(Two photos from Wikimedia Commons. Click on these links to see: portrait of Christopher Columbus by Sebastiano del Piombo, 1519.  Passenger Pigeons by Louis Agassiz Fuertes from a volume of articles, The Passenger Pigeon, 1907 (Mershon, editor))

Amazing as it seems none of the hills in the Pittsburgh Low Plateau were ever mountains.  They were all made by water cutting rock.

When dinosaurs roamed the earth, Pittsburgh was at the shore of a shallow inland sea to our west.  At the time our soil was composed of sandy beaches, mudflats and swamps. The sand became sandstone, the mud became shale, and the decayed swamp plants became coal.

No geologic events deformed our rocks.  To our east the Appalachians slammed into the edge of the plateau and pushed up the Allegheny Mountains.  To our north the retreat of the glaciers made the land rise in a bounce-back from the pressure release.  Our plateau remained essentially flat, tilting slightly to the south and west.  Indeed the rock layers in our area are horizontal.  You can see this at highway road cuts.

But Pittsburgh doesn’t look flat.

Water transformed us, cutting dendritic paths in the landscape as it drained to the inland sea (now the Gulf of Mexico). The paths became deep valleys.  When you stand in a valley you see hills.

Vegetation now hides what happened to the land. You see the hills but none of the water cuts as shown in this view of the Kiskiminetas (Kiski) River at the mouth of Roaring Run.

Take a short hike up Roaring Run and see what water can do.

Here the creek is carving a notch in weak shale.  The valley walls are steep and narrow.  The notch is big enough to wade in.

Eventually Roaring Run may look like the Kiski with tree-covered hills.

It all comes from water cutting rock.

(photos by Kate St. John)

Last week I learned something new.  Did you know that herring gulls are in steep decline?

On Thursday Cornell’s Lab of Ornithology published the 2014 State of the Birds Report in honor of Martha, the last living passenger pigeon who died 100 years ago this month.  The report heralds the great conservation successes of the past 100 years — bald eagles, wood ducks, Kirtland’s warbler, brown pelicans — and warns of species currently in decline that need our attention.

Especially interesting is the list of 33 common birds in steep decline.  According to the report, “These birds have lost more than half their global population. All of these species combined have lost hundreds of millions of breeding individuals over the past four decades.”  We know from the passenger pigeon’s experience that steep decline can quickly lead to extinction so these birds are the ones to help right now.

Many are those I’ve written about in the past — common nighthawks, snow buntings, rusty blackbirds, common grackles — but the herring gull was a real surprise.   How can this species be threatened when we see them everywhere at the shore and the mall?

It turns out that herring gulls nearly went extinct in the 1880’s because of market hunting but made a stunning comeback to 100,000 birds by the 1980’s, thanks in part to humans’ wasteful ways (coastal refuse dumps and fishing boat waste).  Then the tide started to turn.  78% of the herring gull population has disappeared in the last 40 years.  Who knew?

There are plenty of birds who need our help.  Click here for the full report.  We can do it!

And here’s the list of 33 Common Species in Steep Decline.  You’ll find some surprises.

(photo by Shawn Collins)

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 the Syndey Morning Herald science columnist Peter Spinks interviewed two paleontologists, one in the studio and one on the phone.  He asked 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.”  Click here to see Siversson describe why (37 mins).

Woo hoo!

Read more here at Science Matters.

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

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!)

• Droughts:  California, Texas and the winter wildfires in arctic Norway.
• Floods that pollute clean water:  UK floods right now, Mississippi River floods in 2011
• Saltwater intrusion into freshwater aquifers: South Florida drinking water at risk

Others have man-made origins:

• Too many people living in places too dry to support them:  Las Vegas, Sub-Saharan Africa
• Over-demand by agriculture: Click here to watch the Aral Sea disappear.
• Water permanently lost to industrial processes:  Fracking water withdrawals in drought.
• Pollution: The West Virginia chemical spill comes to mind every day.

“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 New Jersey.

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

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)