Oct 25 2016

It’s Bat Week!

Published by under Mammals

In case you haven’t heard it’s international Bat Week.

This week, October 24-31, we celebrate furry flying mammals, learn about their benefits to mankind, and help them survive in our ever changing world.

Did you know these cool facts about bats?

  • There are more than 1,300 species of bats on earth, 40 in the U.S.
  • Bat wings are webs of skin between their fingers (forelimbs).  Bats have more bones in their wings than birds do.
  • Bats have “thumbs” on the leading end of their wings that help them grasp and climb. The tropical Spix’s Disk-winged Bat roosts on leaves so he has suction cups where his thumbs would be.  Click here to see.
  • According to batcon.org, some male bats sing like songbirds to defend territory and attract mates.
  • Most bats reproduce very slowly, only one pup per year.
  • An amazing number of bat species are threatened with extinction — even some that live in Pennsylvania.

Watch the video above to see Rodrigues fruit bats (they’re Critically Endangered) then stop by the National Aviary in Pittsburgh to see the Megabats shown below — Malayan Flying Foxes.

Malayan Flying Fox fruit bat being fed (photo by Denmarsh Photogtaphy courtesy the National Aviary)

Malayan Flying Fox fruit bat being fed (photo by Denmarsh Photogtaphy courtesy the National Aviary)


Happy Bat Week!

Malayan Flying Fox fruit bat, resting upside down (photo by Denmarsh Photogaphy courtesy of the National Aviary)

Malayan Flying Fox fruit bats at the National Aviary (photo by Denmarsh Photography)


Learn more about bats at Bat Conservation International.

(video from the San Diego Zoo, photos by Denmarsh Photography courtesy of the National Aviary)

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Oct 24 2016

The Days Are Getting Longer

Published by under Weather & Sky

Earth rotating on its axis (animation from Wikimedia Commons)

Earth rotating on its axis (animation from Wikimedia Commons)


The days are getting longer.  Really.

Though daylight is decreasing as we head into winter, the length of an Earth day is increasing overall. That’s because Earth’s rotation is slowing down due to tidal forces between Earth and moon, post-glacial rebound, and sea level rise.

The effect is too tiny to see.  It takes 100 years for the day to gain 1.4 milliseconds.  To put that in perspective, a day was 23 hours long for the dinosaurs and is close to 24 hours now.

The only way we can measure Earth’s rotation is by using an array of instruments stationed around the globe (VLBI) that precisely record their first sighting of certain quasars. We then crunch the data to arrive at the length of a day and add a second to our atomic clocks when necessary.

Want to learn how we measure a day?  See the video about quasars at this NASA link.


(*) Quasars emit radio waves so they aren’t actually seen, they’re heard.

(animation of earth’s rotation from Wikimedia Commons. Click on the image to see the original)

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Oct 23 2016

Remnants Of An Explosion

Published by under Weather & Sky

Cygnus Loop Nebula in UV light (photo from NASA via Wikimedia Commons)

Cygnus Loop Nebula in UV light (photo from NASA/JPL-CalTech via Wikimedia Commons)

Something really big exploded 5,000 to 10,000 years ago and this is what’s left.

The Cyngus Loop or Veil Nebula is the dust and gas left over when a supernova exploded in the area of the Cygnus constellation.  The explosion was so bright that people could see it naked eye.

But they didn’t write about it.  The first written language was invented by the Sumerians 5,200 years ago, probably too late for anyone to mention a temporary bright spot in the sky.

Nowadays the remnants are too dim to see without a telescope and some sections such as the Witch’s Broom have been named separately.

The entire Veil, above, isn’t visible except in the ultraviolet range.  If we could see it we’d be impressed.  It’s six times the size of the full moon.


p.s. Many birds can see light in the ultraviolet range, so this is probably what the Veil looks like to them.

(ultraviolet image of the Cygnus Loop Nebula by NASA/JPL-CalTech via Wikimedia Commons. Click on the image to see the original)

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Oct 22 2016

What Is This?

Published by under Plants

What is the name of this vine? (photo by Kate St. John)

What is the name of this vine? (photo by Kate St. John)

What’s the name of this vine?  I ask because I don’t know the answer.

The vine was relatively small when I took its picture in June in Schenley Park.  Now it’s draped over two small trees and climbing a third.  It’s probably an alien invasive.

If you know its name please leave a comment with your answer.



UPDATE at 9:20am:  Thank you, everyone.  Many have commented that this is Canada moonseed (Memispermum canadense).  I’ll go check the vine and its fruit today to see if the rest of it matches up.  I expect to find purple-black berries.

UPDATE, 10/22/16 at 7pm: The vine at Schenley Park has no berries but everything else matches up.

(photo by Kate St.John)

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Oct 21 2016

Mallards Come A’Courting

Even though mallards breed in the spring, they begin courting in September.  In some places 90% of them are paired by the time winter arrives.

Watch them on lakes, ponds, rivers, and in the video above to see these courtship actions(*).

Male courtship moves:

  • Swimming broadside to the female
  • Head sunk in shoulders: an introductory posture
  • Head-Shake: wagging the head from side to side
  • Head-Flick:  arching the neck to the tip of the bill. This ends in flicking the head.
  • Swimming-Shake (not sure I saw this in the video)
  • Several males simultaneously display with:
    • Grunt-Whistle: whistle, then grunt. (the video calls this spitting)
    • Head-Up-Tail-Up (This is my favorite!)
    • Down-Up: looks like bowing

Female courtship moves encourage the males:

  • Nod-swimming: bobs her head up/down
  • Steaming forward:  swims quickly with neck low to the water

Pairing up:

  • Male tries to lead female away by doing Turn-Back-of-Head in front of her.  If she likes him, it works.


Listen for these sounds:  When you hear the whistle, it’s a male courtship sound.  Only the females say “Quack.”


(*) The capitalized terms are from Birds of North America Online.

(video from YouTube via dreamfalcon.wordpress.com)

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Oct 20 2016

Anniversary of The Fox

Published by under Mammals

Red fox crossing a street in Portugal (photo from Wikimedia Commons)

Red fox in Denver neighborhood (photo from Wikimedia Commons)

In autumn young animals leave their birthplace to find a home of their own.  Sometimes they wander into dangerous places — roads, for instance — and sometimes they surprise us.

Seven years ago this month a red fox wandered into my Pittsburgh city neighborhood and spent a couple of weeks in the block near my house.  Our first hint of her presence was the sound of her voice.

On this Anniversary of The Fox, read more about her visit at:

Mystery Solved


p.s. I’m only guessing she was female.  There’s no way to know.

(photo of a fox crossing a street in Denver, Colorado from Wikimedia Commons. Click on the image to see the original)

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Oct 19 2016

Prevent Lyme Disease In Your Own Backyard

White-footed mouse raiding the peanut feeder at night (photo by Rob Ireton, Creative Commons license on Flickr)

White-footed mouse raiding a backyard peanut feeder at night (photo by Rob Ireton, Creative Commons license on Flickr)

If you live in a Lyme disease area and feed the birds, you might get Lyme disease in your own backyard.  Here’s what makes that possible and how you can make your yard safe.

When you provide food for birds, a lot of other animals eat that food as well.  Squirrels and chipmunks eat during the day.  The mice come at night, especially white-footed mice pictured above at a peanut feeder.

Animals live close to their food sources so they live in your backyard or even your house. Here’s a favorite mouse and chipmunk home — the nooks and crannies of stone walls.

Stone wall (located in Vermont, photo from Wikimedia Commons)

Stone wall (photo from Wikimedia Commons)


The abundance of birds and rodents in your yard attracts predators: hawks, owls, cats and even ticks. You’ll see the big predators but you might not notice the tiny ones.  Adult black-footed ticks are very hungry in October and November so watch out.

Chart of black-legged tick life stages (image from Wikimedia Commons)

Birdseed –> mice –> ticks –>  Here’s the Lyme disease connection:  White-footed mice are reservoirs for Lyme disease so the black-footed ticks that feed on your backyard mice may be infected.

What to do?

It’s impossible to get rid of all the mice — even if you stop feeding the birds — but you can get rid of ticks, and that’s what counts in this battle against Lyme disease.

The mice will help you do it.  Mice like soft fluffy bedding in their nests and will carry it into their secret hiding places.  If you give them anti-tick bedding it kills the ticks on them and in their nests.

This ingenious defense is described here at TickEncounter.org.  In their photo below, a mouse is gathering anti-tick bedding — permethrin-sprayed cottonballs — from the blue-green tube.

White-footed mouse with anti-tick tube and cottonball bedding (photo from tickencounter.org)

White-footed mouse with anti-tick tube and cottonball bedding (photo from tickencounter.org)

You can make your own tubes (cottonballs, paper tubes, Permethrin) or buy them complete with instructions at ticktubes.com.  Be sure to read about this technique at Tick Encounter before you begin.  And then …

No more ticks!


p.s. You’ll see at Tick Encounter that July and August are the optimal time for setting out Tick Tubes.  Sorry my timing is off.

p.s. Be sure to read the comments about Permethrin hazards. It is very bad for pets!

(photo credits: Click on the images to see the originals in context
White-footed mouse at night by Rob Ireton, Creative Commons license on Flickr,
Stone wall photo from Wikimedia Commons,
Chart of black-legged tick life stages from Wikimedia Commons,
White-footed mouse with anti-tick tube and cottonball bedding from tickencounter.org

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Oct 18 2016

What Eats Stink Bugs?

Published by under Insects, Fish, Frogs

Stinkbug on a leaf in Frick Park (photo by Kate St. John)

Stinkbug on a leaf in Frick Park (photo by Kate St. John)

It’s warm today but as soon as it turns cold brown marmorated stink bugs (Halyomorpha halys) will try to squeeze into every crack in our buildings.  They’re everywhere.  What can we do?

Ever since these Asian bugs first appeared in North America (in Allentown, PA in 1998) we’ve wondered how to control them.  They destroy crops, especially fruits and tomatoes, so USDA has been studying them for a while.  Do our native species eat them or must we import a stink bug predator from Asia?

To tease out the answer, researchers at USDA-ARS Appalachian Fruit Research Station in West Virginia placed stink bug egg masses near potential predators and documented what happened.

Brown marmorated stink bug eggs (photo by David R. Lance, USDA APHIS PPQ, Bugwood.org)

Brown marmorated stink bug eggs (photo by David R. Lance, USDA APHIS PPQ, Bugwood.org)

Some of the egg masses disappeared.  It turns out that katydids eat the eggs completely, shell and all!

Katydid, Microcentrum species (photo from Wikimedia Commons)

Katydid, Microcentrum species (photo from Wikimedia Commons)

Other egg predators include crickets, ground beetles, earwigs and jumping spiders.

Jumping spiders pick up the entire egg mass, flip it over and suck out the eggs’ contents from the underside. (This is a “daring jumping spider” … cool name, eh?)

Daring jumping spider (photo by Joseph Berger, Bugwood.org)

Daring jumping spider, Phidippus audax (photo by Joseph Berger, Bugwood.org)

Moral of the story:  If you don’t use pesticides, native insects and spiders will do the work for you.  Goodbye, stink bugs!

Read more about the study and watch the videos here in Entomology Today.


(photo credits:
Stink bug on leaf by Kate St. John
Stink bug eggs by David R. Lance, USDA APHIS PPQ, Bugwood.org
Katydid, Microcentrum species from Wikimedia Commons; click on the image to see the original
Daring jumping spider photo by Joseph Berger, Bugwood.org

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Oct 17 2016

The Bridge Moves

Published by under Musings & News

Rainbow Bridge, Utah (photo from Wikimedia Commons)

Rainbow Bridge, Utah (photo from Wikimedia Commons)

The Rainbow Bridge in southern Utah is a bridge of solid rock carved by water during the last ice age.  At 290 feet tall it’s one of the highest natural bridges in the world and held sacred by Native Americans in the region. But it doesn’t stand still. Like all structures it moves in response to vibration.

Last year the University of Utah obtained permission to measure resonance at the Rainbow Bridge.  Their report, published in Geophysical Research Letters, found that the bridge is affected by both natural and human activity.  Wind can make it hum. Waves from man-made Lake Powell on the Colorado River, only a mile away, make it sway a little.  During two days of measurements the bridge felt three earthquakes, one of which was a man-made earthquake in Oklahoma.

The report includes this video of the Bridge’s eight modes of resonance.  The animation is exaggerated so you can see the movements.  “Mode 7” at the 0:23 mark looks positively scary!


Read about how the Rainbow Bridge moves at Resonance in Rainbow Bridge: University of Utah study listens to the natural bridge vibrate and sing.


And speaking of scary bridge movements …

Man-made bridges are engineered to move just a little in response to wind and other forces, but they mustn’t move too much or they break.  In a spectacular case of poor design the Tacoma Narrows Bridge, built to withstand 120 mph winds, collapsed on 7 Nov 1940 in a 40 mph wind only four months after it opened.  The cause was attributed to resonance, though more recently to aeroelastic flutter.  Watch the bridge collapse below. Read the whole story here.


(photo credits:
Rainbow Bridge from Wikimedia Commons, click on the image to see the original.
video of Rainbow Bridge from University of Utah
Video of Tacoma Narrows Bridge collapse by Barney Elliot, 7 Nov 1940 via Wikimedia Commons

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Oct 16 2016

This Morning’s Outing in Schenley Park

Participants in Schenley Park outing on 16 October 2016 (photo by Kate St. John)

Participants in Schenley Park outing on 16 October 2016 (photo by Kate St. John)

This morning it was jacket weather with lots of dew (wet shoes!) as 14 of us gathered at the Bartlett Shelter in Schenley Park.

We found plenty of birds — at least in terms of individuals.  Not only were there many blue jays and robins but midway through the walk several hundred common grackles showed up to snatch the bread cubes scattered beneath the oaks near Bartlett Shelter.

A low-swooping red-tailed hawk kept the chipmunks and jays on their toes and a flock of cedar waxwings stopped in to eat porcelain berries.

Best Bird: Blackpoll warbler.   Fall blackpoll and bay-breasted warblers have many of the same field marks — warbler size, thin warbler beak, wing bars, yellow wash on throat, faint eyeline, olive back with subtle stripes, faint stripes on chest — but blackpolls have orange feet and sometimes orange legs, too.  This one was immature with black legs and and orange feet. Click here and scroll down to see an immature blackpoll up close.

Best mammal: We saw a very plump raccoon climb a tall tree and finally insert itself into a hollow space at the top.  “Insert” is a good description.  The raccoon was so plump that it took a while for him to ooze into the crack and disappear.  Perhaps he exhaled to make himself thin.

Here’s the complete list of birds.  (You’ll notice that I didn’t count most of them — too hard to both to count and lead.)


(photo by Kate St.John)

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