Archive for December, 2011

Dec 11 2011


Published by under Beyond Bounds,Trees

Standing alone like a "wolf tree" in a farmer's field, this tree looks quite odd.

Grandidieri's baobab (Adansonia grandidieri) grows only in the western part of Madagascar, an island off the coast of Africa.   As is typical for baobabs it has a very wide trunk compared to its crown.  Of the eight baobab species on earth, six are endemic to Madagascar.

If surrounded by a forest this tree would not stand out.  At 80 feet tall it's about the height of a red oak and would blend in from a distance.  But its trunk is 10 feet wide, three times the diameter of a red oak.  This is one fat tree!

The IUCN says that Grandidieri's baobab probably occurred in dry deciduous forests close to water but is now found in degraded agricultural land.  Sadly this is typical of Madagascar where deforestation is a huge problem.

That's why this baobab is endangered ... and more unusual than it ought to be.

(photo by Bernard Gagnon on Wikimedia Commons.  Click on the photo to see the original.)

4 responses so far

Dec 10 2011

What’s That Smell?

Published by under Mammals

An unpleasant smell is coming from the crawl space under our kitchen sunroom.

I first noticed a hint of it on Wednesday evening but I couldn't find the source though it seemed strongest in the basement.  Day after day the smell has increased until this morning it is noticeably putrid.  I think something died in there.  But what?

The only access to the crawl space is from inside our basement ... unless you're a mouse ...  and that was the last known location of the mouse I couldn't catch last month.  I thought he was in the heating duct but no, he was probably walking on the heating duct while collecting that pile of pink insulation you see in center of the photo.  That pile is new and unreachable by humans. No wonder he never found the trap I set upstairs.

When my mouse adventures began I put two snap traps in the crawl space but they went untouched for days.  I worried that my cat, Emmalina, would explore the crawl space so I removed the traps when I became convinced the mouse was inside the ductwork.

Since Thanksgiving I haven't heard the mouse at all so I thought he was gone.  Dang!  I feel like I flunked Nature Observation.  I made up for my mistake this morning by again installing snap traps in case the mouse has friends.

So now the house smells bad when the furnace runs and my imagination is working overtime.  How long will it take for the smell to go away?  What if that smell is poop and not death?  What if the critter is still alive?  What if it's a rat?

I have a feeling I'm going to buy way too much anti-rodent gear today.

(photo by Kate St. John)

p.s. That brown spot in front of the insulation is a rock, not a mouse.

5 responses so far

Dec 09 2011

Masters Of Camouflage

Published by under Water and Shore

If you haven't seen this video already you don't want to miss it.

Back on August 5, Science Friday featured this four minute program that shows how cephalopods (squid, octopus and cuttlefish) are able to camouflage themselves in an instant.

Before you click to play the video, can you see the octopus clinging to that sea plant?

(video from this article on Science Friday)

One response so far

Dec 08 2011

There’s Something In The Air

As I've snapped photographs of bark for my winter tree identification series, I've had no trouble finding clean, lichen-free trees in Schenley Park.  It turns out the lack of lichens is bad news for our air quality.

Lichens are two organisms that operate as one, a symbiotic partnership of a fungus with a green or blue-green algae (sometimes all three).  The algae's photosynthesis feeds the fungus.  The fungus gathers and retains water and nutrients and protects the algae.

This amazing combination allows lichens to thrive in some of the harshest habitats on earth but they're sensitive to air pollution.  The ones that grow on trees are epiphytes, totally dependent on the surrounding air and precipitation for their nutrition.  Ultimately their tissues absorb elements in concentrations that mimic what's in the air.

We've known for a long time that there's a correlation between the absence of lichens and poor air quality.  Back in 1866, the Finnish botanist William Nylander showed that lichens were present in the Luxembourg Gardens that had disappeared from the polluted sections of Paris, France.  Sadly, air pollution increased in Paris and within 30 years the Luxembourg Gardens' lichens had disappeared as well.

Lichens are used in air quality studies today because they are widespread, accurate indicators and far less expensive than man-made monitors.  You don't have to be an expert to participate.  In the 1960's schoolchildren in Great Britain gathered data in a nationwide lichen-based air quality study that produced the "Mucky Air" map.  Here's a list of a few more recent lichen studies:

Even if you can't identify lichens you can make a rough guess of the local air quality by the types of lichens you see.  Basically, “the further it stands out from the tree, the cleaner the air.”  Crusty lichens (crustose) are the hardiest because they have the least surface area, leafy (foliose) lichens are in the middle, shrubby (fruticose) lichens are the most sensitive.  Hypogymnia physodes, a foliose lichen pictured above, is often used as an indicator species because it's widely distributed and it "stands up."  I've seen lichens like this in Maine but not in Pittsburgh.

Lichens are especially sensitive to sulfur dioxide (SO2).  So are people.  In Pennsylvania most of our SO2 is produced by coal-burning power plants and coking facilities.   High SO2 causes respiratory distress and triggers asthma so it's been regulated since the Clean Air Act of 1970.  Lichens have rebounded in many areas of the U.S. since then.

In June 2010 EPA issued tighter 1-hour SO2 standards (75 ppb, measured hourly) to protect public health from high short term exposures ranging from 5 minutes to 24 hours.  Because we've been measuring SO2 for so long, we already know that the Pennsylvania counties of Allegheny, Beaver, Indiana and Warren have exceeded the new SO2 standard.  Coal-burning facilities in these counties will have to control their SO2 emissions even further.  As they do, we'll all breathe a little easier.

And we'll have more lichens in the future.

(photo in the public domain from Wikimedia Commons. Click on the photo to see the original.)

5 responses so far

Dec 07 2011

Winter Trees: Honeylocust

Just after Thanksgiving the tree cutters visited my neighborhood.  Hired by Duquesne Light, they trimmed or cut down every tree they found near the electric lines at Magee Field.

After they were gone I went to check the damage.  Did they cut down the honeylocusts whose pictures I'd taken the week before?

One look at the trunk of a honeylocust (Gleditsia triacanthos) and you know right away you don't want to touch it.  The tree is protected by huge clusters of branching 3-inch-long thorns quite capable of impaling your hand.

The thorns are diagnostic.  No other tree in Pennsylvania has them(*).

The twigs are distinctive, too.  They're stout, zig-zagged and tapered but there's no need to remember that because the thorns stand out.  They're reddish-brown, thick and branching just like the thorns on the trunk.  Hawthorn trees have thorns but nothing like this.  Theirs are long, slender and unbranched.

Here's a picture of the twig showing the tip of my thumb while I gingerly hold it against the paper.  The longest thorn is as long as my thumb!


So did the tree cutters take down the honeylocusts?

No.  Of course not!

(photos by Kate St. John)

* p.s. The closely related waterlocust has similar thorns but doesn't grow in Pennsylvania.

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Dec 06 2011

A Roosting Nest

Now that the leaves are off the trees you can see birds' nests that were used last summer.  The nests are abandoned now because most birds don't use them outside the breeding season. 

The cactus wren is an exception.  The male and female build a selection of domed stick nests in the cactuses in their territory, usually in prickly pear or cholla.  You can see a nest hole in the middle of this photo of an old-man cactus.

The nests provide good protection from weather and predators so after the breeding season is over the wrens continue to roost in them.  Most of the time the cactus spines keep the birds safe, though some very careful climbing snakes can successfully raid the nests.

Here's what the owner of such a nest looks like.  This cactus wren appears to be taking a dim view of the photographer.


Roosting in one's nest may be a wren trait.  On Sunday Marcy Cunkelman told me that a Carolina wren is again roosting in the woven nest on her front porch

Have you noticed this among wrens in your area?

(photo of nest in the public domain on Wikimedia Commons;  photo of cactus wren by Mark Wagner from Wikimedia Commons.  Click on each photo to see its original.)

3 responses so far

Dec 05 2011

Sky Shadow, Tyndall Effect

Published by under Weather & Sky

How can a building cast a shadow on the sky?  The label on this photograph explains it:  Tyndall effect at CN Tower, Toronto.

The Tyndall effect was new to me so I looked it up.  Named for physicist John Tyndall (1820-1893), it describes how light is scattered as it passes through a colloid.

A colloid is a gas, liquid or solid that has particles microscopically and evenly dispersed within it.  Both natural and man-made colloids exist.  Some natural examples are fog, smoke, milk and gelatin.  Opals are colloids whose beauty comes from the Tyndall effect.

In this photo the air is a colloid.  Some of the particles in it are natural (water droplets and dust), some are man-made (fine particulate pollution that generates smog).  In either case the particles scatter sunlight and we can see the beam of sunlight.

Despite reading a lot about it I didn't really understand the Tyndall effect until I watched this educational video.  The narrator first shows that a laser beam cannot be seen as it passes through plain water.  Then he puts two drops of Dettol (a cleaning product) into the water and the laser beam appears.

Pretty cool, huh?

So when you see a shadow on the sky, you know there's something in the air.

(photo by Wladyslaw, a featured picture on Wikimedia Commons. Click on the photo to see the original.  Video posted by ksvsrao on YouTube.)

One response so far

Dec 04 2011

First Hard Frost

On Friday we had the winter's first hard frost in the city.

I say this based on my observation of the plants in Schenley Park.  Prior to December 1 we'd had some lightly frosty mornings and one big snowfall in late October, but no frost so hard that the plants broke under it.  Some non-native species continued to bloom.

On Friday the plants broke.  On Saturday the frost peristed until the sun turned it into swirling steam.

Winter is officially here.

(photo by tracy from Wikimedia Commons)


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Dec 03 2011

Job Opening Filled

Published by under Peregrines

In Youngstown a "job opening" for a resident female peregrine was filled last month by this bird.

Dorothy's son, Stammy, and his mate Stellar had nested in Youngstown since 2005 but Stellar died last summer.

Peregrines in need of a good nest site go wandering in the fall and those in need of a mate advertise their availability.  I'm sure Stammy hoped a female would notice him in Youngstown -- and one did. By early November peregrine watchers saw Stammy courting with a new lady.

Last Monday Chad and Chris Saladin stopped by Youngstown for a look and identified her as Strike, hatched in 2009 at the Cleveland Terminal Tower nest.

Chris wrote, "Strike spent this nesting season in the Cuyahoga Valley National Park at the Station Road Bridge nest site. She and McKinley had two chicks, but both chicks died in the nest. We saw Strike fly into the nearby CVNP Turnpike Bridge nest territory, where she had a couple skirmishes with the resident female, Lara, and hadn't seen Strike since. "

I'm glad that Strike found Stammy.  I hope their 2012 nest is a great success.

(photo by Chad+Chris Saladin)

6 responses so far

Dec 02 2011

Photography Workshop at the National Aviary, Jan 7, 2012

Published by under Books & Events

I don't own a camera but I love great bird photos, so this workshop caught my eye.  Maybe some of you would like to attend. 

What: Photography Workshop at the National Aviary, Pittsburgh, PA
Who:  Led by National Aviary educator and professional photographer Nicole Begley
When: Saturday, Jan. 7, 2012.  2:30-4:30 pm
Cost: Special Member price   $36

Click on the photo above to read all about it on the National Aviary website.

(image from the National Aviary)

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