Feb 13 2013

Pepper On The Snow

Published by under Insects, Fish, Frogs

Snow fleas near a log (photo by Marianne Atkinson)

Have you ever seen pepper on snow?  Did the pepper jump when you approached?

Last weekend Marianne Atkinson found black sprinkles on the snow near her home in Clearfield County, PA.

The “pepper” is hard to see in her first photo. Here’s a closeup.

Several snow fleas (photo by Marianne Atkinson)

 

These are snow fleas (Hypogastrura nivicola), a springtail species that earned its name because it appears on top of snow on warm winter days and, like all springtails, it jumps like a flea to avoid danger.

Springtails as a group are very interesting creatures:

  • They are very small, less than 0.24 inches long.  To see them well you have to magnify them.
  • They have a spring-loaded furcula (like a tail) that they clasp under their bodies.  When they let go the “tail” whaps the ground and propels them into the air.
  • Springtails are technically hexapods, not insects.
  • Most springtails live in leaf litter and topsoil where they eat decomposing plants and animals.
  • They are very gregarious.
  • They are highly sensitive to drought. Because they breathe through their cuticle (hard skin) they can’t afford to dry out.
  • Springtails are a sign of good soil because they are very sensitive to herbicides, pesticides and pollution. Folsomia candida are used in the lab for soil toxicology tests because they avoid — or die of — chemicals at very low levels.
  • There can be 100,000 springtails in one cubic meter of soil, making them one of the most abundant macroscopic animals on earth.

Snow fleas themselves are extra special.  They are active in winter because they have a protein in their bodies that works like anti-freeze.

Sometimes it’s the little things that are the most fascinating.

(photos by Marianne Atkinson)

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Feb 12 2013

Sounds Like A Typewriter

White-winged Crossbill, male (photo by Heather Jacoby)

This winter in addition to irruptions of evening grosbeaks and redpolls, crossbills have come to Pennsylvania.

I’ve seen white-winged crossbills before, especially in the winter of 2009, but this year they’ve eluded me.  People send news of them to PABIRDS but when I travel to their reported location they aren’t there.  True to their irruptive nature crossbills are always on the move.  Dang!

Last week I ran into Claire Staples while on my lunch break in Oakland.  We exchanged bird sightings and Claire said she’d experienced the same problem finding crossbills until quite recently when she heard them near her home in Squirrel Hill.

The clue is their sound.  Claire says they sound like typewriters, a useful tip as I actually do remember what typewriters sound like.  Shows how old I am!

So now on my walks I’m trying hard not to look for crossbills as I don’t want to jinx my chances of seeing them.  But I’m listening for the sound of typewriters.

(Click here to hear.)

(photo by Heather Jacoby)

7 responses so far

Feb 11 2013

An Icy Parfait

Published by under Weather & Sky

Sea ice in the Arctic (photo courtesy Univeersity of Washington)

Even when scientists develop an answer to why something happened, they still test the idea to make sure they’re right.

That’s what happened with the Great Arctic Cyclone of August 2012.

Last August a rare, massive cyclone formed in Siberia and swirled out over the Arctic Ocean for days.  During its transit the sea ice disappeared faster than anyone had ever seen.  (See the swirl here.)

By September Arctic sea ice was at an all time low.  Some said the cyclone caused the lowest ice extent since record-keeping began.  Did it?  Or would the ice have melted anyway due to warm temperatures?

Scientists at the University of Washington’s Applied Physics Laboratory ran two computer simulations of last summer’s Arctic weather.  One matched the actual weather.  The other included everything except the cyclone.

The result showed that yes, “the effect is huge in the immediate aftermath of the cyclone, but after about two weeks the effect gets smaller.  By September, most of the ice that melted would have melted with or without the cyclone,” said lead author Jinlun Zhang.

Why?  Because of mixing.

Back in September most thought that the wind broke up the thin ice or pushed it into a warmer part of the ocean.  Since then scientists have learned that the ocean underneath the ice is like a layered parfait.  Just below thin ice is a layer of ice-cold fresh water.  About 65 feet down is a layer of salty water warmed by the sun.  The cyclone stirred the parfait.  The ice was exposed to the warm water beneath and it melted.

The cyclone did cause the ice to melt 10 days sooner, but in the end it made less than 5% difference in the ice extent.

So yes, the sea ice melted because it was hot last year.

Click on the photo to read more about the study in Science Daily.

(photo courtesy University of Washington)

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Feb 10 2013

Count Birds Next Weekend

Published by under Books & Events

White-breasted nuthatch (photo by Marcy Cunkelman)

Fill your feeders and get ready!  The Great Backyard Bird Count kicks off this Friday February 15.

For four days — February 15 through February 18 — you can take part in this easy citizen science project from the comfort of your home.  All you need to do is count birds for at least 15 minutes, keep track of the highest number of each species you see, and record your count here.

If you don’t have feeders, you can count birds anywhere.  If you photograph birds, submit your pictures for the GBBC Photo Contest.

Count for hours or for as little as 15 minutes.  Have fun!

Read more here on how to participate in the Great Backyard Bird Count.

(photo by Marcy Cunkelman)

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Feb 09 2013

Easy To See In Snow

Horned Lark (photo by Bobby Greene)

In snow-covered fields horned larks are easy to see because their brown backs don’t completely blend into the background.

Without snow these birds match the dirt.  The only way I find them is by luck — I hear them and then search for movement in the mud.

When the blizzard finally ends on the East Coast today, it will be easy to see horned larks against all that snow.  In the meantime in Pittsburgh our snow will melt in tomorrow’s 50 degree temperatures.

Despite the challenge of muddy fields I think I’d rather have a hard time seeing horned larks.  ;)

(photo by Bobby Greene)

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Feb 08 2013

Extinction By Rabbit

Laysan Rail (drawing by Walter Rothschild from Wikimedia Commons)

On Monday I wrote about cats and windmills as threats to bird life but neither of them are the leading reason why birds die.  The number one cause of bird death worldwide is habitat loss.

The Laysan rail, pictured above, went extinct in the 20th century because of habitat loss with a bizarre twist.

Laysan is a small, isolated island in the middle of the Northwestern Hawaiian Island chain.  Only 1 by 1.5 miles across its land area is 1,016 acres, about twice the size of Schenley Park.

Laysan is famous for its bird life, a nesting island for many Pacific seabirds and home of the rare Laysan albatross and even rarer Laysan duck.  It was also the home of the Laysan rail, a fearless, flightless bird less than 6 inches long.

Unfortunately, in 1903 Max Schlemmer released rabbits on the island as a money-making venture.  Instead of making money it was the beginning of the end.  The rabbits on Laysan had no predators and in short order they overran the island.  (Keep in mind that a rabbit can bear 35 young per year.)  The rabbits ate everything.  Everything.

By 1918 Laysan was a barren dustbowl on which only 100 rabbits survived.  With little to eat and no cover the Laysan rail population was hanging on by a thread.  Meanwhile a few rails had been introduced to other islands in the northwestern Hawaiian chain in hopes they could survive elsewhere.

In 1923 the Tanager Expedition eradicated Laysan’s rabbits but it was too late for the rail.  The last two on the island died that year.  A few hung on at other islands in the chain but the final blow fell in 1944 when a World War II ship drifted to shore on Eastern Island, Midway and the ship’s rats swam ashore.  The rats ate the last Laysan rails on earth. That was that.  Extinction.

In the broadest sense, loss of habitat killed the Laysan rail.  In a narrow sense it was a case of extinction by rabbit.

(drawing by Walter Rothschild from Wikimedia Commons. Click on the image to see the original.  Today’s Tenth Page is inspired by page 640 of Ornithology by Frank B. Gill.)

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Feb 07 2013

Dorothy Drops In

Published by under Peregrines

Dorothy drops by during videocam installation, 6 Feb 2013 (photo by Mike Faix, National Aviary)

On Tuesday morning, amidst fog and drizzle, four intrepid men from the University of Pittsburgh, PixController, and the National Aviary visited the Cathedral of Learning to replace the peregrines’ streaming nestcam.

Last year the old camera stopped displaying color in bright sunlight.  Ideally its replacement would have been installed in January when the peregrines weren’t territorial but scheduling was a problem.  High winds a week ago postponed the trip until February 5.

At first the peregrines were nowhere to be seen, probably because the fog kept them drowsy at their roosts.

Dave Marti (Pitt), Bill Powers (PixController) and Chris Gaus (National Aviary) worked undisturbed in the photo below.  Mike Faix (National Aviary) was on the ledge too but not visible in this picture.  The work area is so small that everyone has to stand in a row.

Dave, Bill, Chris at the streaming cam install, 6 Feb 2013 (photo by Kate St. John)

 

The effort took longer than expected and Dorothy got tired of roosting.  Even though it was drizzling she dropped by to see what was happening (above) and Chris held out the broom so she would keep her distance.

The new camera is now in place and will start streaming in a few weeks.  Thank you to everyone who made this peregrine nestcam possible.  To…

  • The University of Pittsburgh for hosting the peregrines’ nest and cameras.
  • Phil Hieber of Facilities Management who makes all the arrangements and keeps the peregrines in mind whenever there’s Cathedral maintenance …  and to Dave Marti & his toolkit.
  • Bill Powers and and PixController for camera expertise.
  • The National Aviary’s Urban Peregrine Program that hosts the falcons’ website (that’s Teri Grendzinski, Chris Gaus and Mike Faix).
  • And to everyone who donated to the National Aviary to make this camera possible.

By the end of February, Dorothy will drop by more often.  ;)

(peregrine/broom photo by Mike Faix, installers’ photo by Kate St. John)

2 responses so far

Feb 07 2013

A Trip To See The Trumpeters

Published by under Water and Shore

 

Heavily hunted for meat and feathers, trumpeter swans nearly went extinct in the early 20th century, disappearing from all but a small range in Alaska and Canada.

When the swans were at their low ebb, states and provinces established reintroduction programs in the 1970’s and 1980’s in Ontario, Minnesota, Wisconsin, Michigan, and (an introduction program in) Ohio.

Because of the Ohio program we now see trumpeter swans occasionally in western Pennsylvania, but if you want to see a really large flock the place to be is along the Mississippi River at Monticello, Minnesota in mid-winter.  They’re there because the water is ice free, thanks to a nuclear power plant upstream.

Sparky Stensaas, the Photonaturalist, visited last month and produced this video.

Read his blog for more information about the Monticello trumpeters.

Wow!

(video by Sparky Stensaas)

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Feb 06 2013

Dogs To The Rescue

Max, a member of the University of Washington's Conservation Canines program, pauses after locating a northern spotted owl roosting in a tree in the Shasta-Trinity National Forest. (Credit: Jennifer Hartman/U of Washington)

How do you survey a population of owls who are afraid to make noise?  Dogs to the rescue!

In 1990 northern spotted owls were listed as Threatened under the Endangered Species Act.  Since then their population has been surveyed year after year, but despite changes in logging practices northern spotted owls continue to decline 3.7% per year.

Part of the problem could be that some owls have fallen silent and are impossible to count.   The typical survey method is to play an owl recording and listen for the owl to respond.  But barred owls have infiltrated the old growth forest, displaced northern spotted owls, and sometimes killed them.  Some northern spotted owls would rather not respond when the tapes are played.  They don’t want to give themselves away.

So how do you count these owls?

Researchers at the University of Washington trained two dogs, Max and Shrek, to identify owl pellets by species!   Amazingly, the dogs can smell the difference in regurgitated mouse bones from a barred owl versus a northern spotted owl.

The team takes the dogs out for a spin in the forest.  They don’t use recordings at all.  The dogs sniff for pellets below owl roosts and are so good at identifying the species that they have a 30% better success rate at finding northern spotted owls than the recordings do.

Here’s Max triumphant.  See the northern spotted owl in the tree above him?

Good dog!

Read more about Max in the Science Daily press release.

(photo of  Max, a member of the University of Washington’s Conservation Canines program, by Jennifer Hartman, Univ of Washington)

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Feb 05 2013

Occupational Hazard

Barred owl at Crooked Creek (photo by Steve Gosser)

How do owls turn their heads this far without killing themselves?

Trauma experts know that when humans turn their heads too far or too fast the arteries to the head are stretched or torn, cutting off the blood supply or producing blood clots that can kill.

Why doesn’t this happen to owls?  A team at Johns Hopkins decided to find out.

Led by medical illustrator Fabian de Kok-Mercado, they used imaging technology on barred, snowy and great horned owls who had died of natural causes. The researchers found four adaptations that make the owls’ wide range of movement possible:

  1. As in humans, the major arteries that feed the brain go through bony holes in the vertebrae but in owls these holes are 10 times larger than the arteries, allowing them to move within the hole without pinching.
  2. The owls’ vertebral artery enters the neck higher up than in other birds — in the 12th vertebrae rather than the 14th.  This provides more slack.
  3. When an owl turns its head the arteries at the base of the head balloon to take in more blood.  In humans the arteries get smaller and smaller.
  4. Owls also have small vessel connections between the carotid and vertebral arteries so if one path is blocked the other still works.

A simple turn of the head that’s so hazardous to us is all in a day’s work for an owl.

Read more about the study here in Science Daily.

(photo of a barred owl by Steve Gosser)

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