Archive for the 'Musings & News' Category

Oct 07 2013

On Caffeine

Spider webs with and without the spide on caffeine (photo from Wikipedia)

This blog is made possible by caffeine…  administered every morning in a 16 oz mug of coffee at 5:00am.  Boing!  I’m awake!   It works.  And it makes me happy.

Apparently it is not good for everyone.

According to Wikipedia, Swiss pharmacologist Peter Witt began testing different drugs on European garden spiders in 1948 because a zoologist friend of his, H. M. Peters, was annoyed that the spiders always wove their webs between 2:00am and 5:00am.  Dr. Peters wanted to study web building when he was awake, not when the spiders were.

Naturally it made sense to try caffeine.  Perhaps it would keep the spiders awake longer so that they’d “sleep in” and start weaving after dawn.

Not so!  Instead of time-shifting their web construction, caffeine made the spiders build whacky dysfunctional webs.

In 1995 NASA conducted a similar study and took photographs of the spider webs both before and after caffeine (above).

So much for Dr. Peters’ brilliant idea.  He was forced to study his subjects in the dark.  I’m sure he had to be on caffeine to do it.

Happy Monday.

(photos from Wikipedia. Click on the image to see the original)

5 responses so far

Oct 01 2013

Starling Story Problem

European starlings (photo by Bobby Greene)

When I was in grade school I hated Story Problems in math class — those word problems without formulas, just a bunch of facts to solve.

But life is full of stories.  I overcame my disgust, learned how to turn word problems into formulas, and became a math major.  Thus when I wrote about starling flocks last Friday I began to wonder…

How did the starling population increase from 100 birds released in Central Park in 1891 to 200 million (or more) in 2013?

Using information on their breeding habits and survival rate, I did some crude mathematics and came up with an answer.  First, the facts:

  • Starlings north of the 48th parallel produce only one brood per year, the rest produce two.  (To give you an idea of this location, the western U.S.-Canada border is at the 49th parallel.)
  • Female starlings typically lay 5 eggs per nest.
  • 50% – 80% of the eggs survive to the fledgling stage.
  • 20% of the fledglings survive to adulthood.
  • 60% of the adults survive each year.

(Warning!  If math makes your head spin, now’s the time to skip to the end.)

If we started with 100 starlings in Pittsburgh this spring, how many starlings would we have next spring?   To make it simple I made some big assumptions and did a lot of rounding.

  • 100 starlings = 50 nesting pairs
  • 50 pairs * 2 nests per year * 5 eggs per nest = 500 eggs this year
  • 50% to 80% of the eggs will fledge.  I used 65% * 500 eggs = 325 juvenile starlings in August.  I rounded this down to 300.
  • 100 adults + 300 juveniles = 400 starlings in August.   This is why we see so many starlings in the fall — and this doesn’t even include the migrants.
  • 60% of the adults survive to the next spring = 60% * 100 = 60 adults in March
  • 20% of the juvies survive the winter = 20% * 300 = 60 former juveniles in March
  • 60 adults + 60 of last year’s juveniles = 120 starlings in March

If I’m right (but I’m not) our starling population increases 400% in August, then winter trims it to an annual increase of 20% by March.

But 20% is too high.  Sixteen pairs survived from the 100 birds released in Central Park in 1891.  If their increase had been uniform it would resemble compound interest over 120 years (1891 to 2011) of about 14%.

(If you skipped the math, join me here.)

Interestingly, scientists estimated that the starling population boom in the western U.S. in the 1970’s was 16% per year, so I got close.

Fortunately the starling population seems to have stabilized so their annual increase is now — perhaps — zero.

How’s that for a story problem?

 

(photo by Bobby Greene)

3 responses so far

Sep 12 2013

No Food, No Water

Mount Desert Rock (photo by krzdweasel, Creative Commons license)

Twenty miles off the coast of Mount Desert Island is a tiny granite outcrop called Mount Desert Rock.  On a clear day you can see it with binoculars from the mountains of Acadia National Park. It looks like an improbable ship, taller than it is long.

Only 3.5 acres in size, Mount Desert Rock holds three buildings and a lighthouse just 17 feet above sea level. During winter storms and hurricanes the ocean washes over the island and punishes the buildings. The boathouse was swept away during Hurricane Bill in 2009. Isolated and exposed the Rock stands alone. Click here to see how small it is.

Map showing location of Mount Desert Rock (image from Wikimedia Commons)

Whale watching tours from Bar Harbor sometimes circle the Rock.  That’s how I’ve come close but never landed.  The Rock has no harbor so even those authorized to land can only do so when the sea is calm.

Lighthouse keepers and their families used to live year-round on the island, sheltering in the lighthouse during storms.  Since 1998 the College of the Atlantic has had whale and seal study crews posted there on temporary assignment, but they leave before a storm.

No matter who is stationed there, they must survive on food and water shipped from the mainland.  Rainwater is collected in a cistern under the keepers’ house but it’s undrinkable.  Nothing can grow there because the ocean washes away the topsoil in every storm.  And there is noise: The foghorn blares every 30 seconds.

When the weather is right, songbirds take a shortcut across the Gulf of Maine during fall migration from Nova Scotia to Maine.  From the whale watch boat I’ve seen ruby-throated hummingbirds and robins pumping their way past the Rock to Mt. Desert Island 20 miles away.  It’s scary to think they are over open water, sometimes fighting the wind, spending themselves to make landfall on the shores of Acadia — or else they will die.

Fly safe, little birds.  The Rock is no place to rest.  No food.  No water.

(photo by “krzdweasel” via Flickr, Creative Commons license.  Click on the image to see the original. Map from Wikipedia.)

2 responses so far

Aug 27 2013

This Makes It 2,000

Published by under Musings & News

Fireworks (photo by Jon Sullivan via Wikimedia Commons)

Riffing on the number 2,000… yesterday I wrote about a hummingbird drawing 2,000 years old.  Today…  Ta dah!  This is my 2,000th blog post!

Almost six years ago I began blogging every other day.  By now I write daily posts and more when there’s breaking peregrine news.  My husband notes that this sustained effort is roughly equivalent in length to War and Peace.

That’s a heck of a lot of writing, so for today I’m going to take a break and encourage you to do two things using the panel on the left:

1.  Try the search box.  Find something interesting in my other 1,999 entries.  Search for anything — a noun, a verb, an adjective.  Below you can see that I searched for the word “intriguing.”  Scroll down to read older posts you may have missed.

2.  Donate to the blog.  My blog is hosted at WQED Pittsburgh, where I work as Director of Information Technology for both TV and radio.  Like all public broadcasting stations we rely on donations to keep us going.  If you like this blog, make a donation of any size to show your support.  Click on the hummingbird graphic.

Thanks!

p.s. The screenshot below shows you what to do.

Screenshot from Outsdie My Window: How to celebrate the 2000th

 

(photo of fireworks in the public domain from pdphoto.org via Wikimedia Commons. Click on the image to see the original)

7 responses so far

Aug 26 2013

2000-Year-Old Drawing of…

Published by under Musings & News

Retouched photo of Nazca hummingbird (photo from Wikimedia Commons)

Here’s a 2000-year-old drawing of a very cool bird.  Can you tell which one it is?  (For a better view, click on the image to see the larger original.)

While researching hummingbirds I learned about this geoglyph, one of the many Nazca lines found on the dry landscape of southwestern Peru near the towns of Nazca and Palpa.  From the air the land looks like a giant sketchpad with hundreds of geometric figures, humans and animals.  There are even erasures and newer drawings superimposed on top of old ones.

The Nazca people created these lines when their culture thrived here between 200 BC and 600 AD.  The figures were community projects created by removing the top layer of dark reddish pebbles to reveal the light-colored soil beneath.   This desert is one of the driest places on earth and so stable — no wind, rain or vegetation — that the lines have endured to this day. They were protected as a UNESCO World Heritage Site in 1994.

The geoglyphs are as large as 660 feet across, some drawn on hillsides like murals, others in the valley.  The hummingbird is 310 feet long and is a single line that can be walked without crossing itself.  Archaeologists believe these walks were ceremonial, possibly done as a group or community.

I’m impressed that people can create a shape on this scale.  The artist has to spatially translate a small drawing into landscape size.  I can do this for easy things such as “walk in a circle in the living room” but nothing like this!   (In Pittsburgh we’ve done this like flash mobs that spell Google or make the shape of a Pitt Panther.)

Line-making in the Peruvian desert ended after 800 years because of local climate change.  The Nazcas’ only water came from horizontal wells and intermittent rivers fed by rain on the western slopes of the Andes.  When that rain ceased to fall, the wells and rivers went dry and that was that.

See more of the drawings in this six minute slideshow.

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

4 responses so far

Aug 21 2013

Rescued!

Great egret trapped in high-strength fishing line (photo by John Beatty)

When fishermen and trappers abandon their lines in the water, they hurt unintended victims.  One careless individual nearly killed a great egret in York County, Pennsylvania.

Thanks to John Beatty, Ann Pettigrew, TriState Bird Rescue and a whole host of caring volunteers the bird was saved.  Here’s the story in John Beatty’s words:

On August 8th 2013 at William Kain Park I noticed an Egret was trailing behind some high-strength fishing line with a hook attached inside of the corner of its mouth. It was later discovered that this line was left behind by someone attempting to catch Snapping Turtles in the lake. I called the Fish & Game Commission and they dispatched out an officer but before he arrived a couple of local York County Parks employees happened to stop by as well. With a coordinated effort they were able to corral this bird into the woods, capture and retrieve it. By another coincidence there happened to be a veterinarian (Ann Pettigrew) of the Leader Heights Animal Hospital out taking photographs and she offered her help to bring the bird back to her office. The hook was removed from the bird’s throat and after being treated and nursed back to health it was released on August 18th. It was very nice that they invited me to come and take photos at the release of the bird.

Above, the egret struggles to remove the line but the hook is lodged in his throat.  In fact it has gone through and is protruding from his neck.

Below, county park naturalists Fran Velazquez and Kelsey Frey slogged through mud, water and thorns to catch the bird.  Wrapped in a towel, they are holding its beak (through the towel).  You can see its black feet near Kelsey’s gloved left hand.

GREG_rescue_9464685065_c040a60d68_c_rsz_johnbeattyGreat egret captured to rescue it from fishing line (photo by John Beatty)

 

At Leader Heights Animal Hospital, Dr. Ann Pettigrew removed the hook and heavy-duty string and treated the bird. Then she took it to Tri-State Bird Rescue for rehab.  In only ten days it was healthy and ready for release.

On August 18 everyone turned out to see the bird fly free.  Here Teresa Deckard of Bird Refuge of York County opens the box.

Great egret released (photo by John Beatty)

That’s one happy egret!

Thanks to all the good people who made this happy ending possible.

Don’t miss John Beatty’s beautiful photos of this egret’s rescue and release.  Click here or on any of the photos to see the entire story.

(all photos by John Beatty)

 

p.s. In the Comments I have transcribed Ann Pettigrew’s PABIRDS report of this egret’s rescue on August 8.

4 responses so far

Aug 16 2013

No Birds Here

Downtown Pittsburgh from the Ft Pitt Bridge (photo from Wikimedia Commons)

Which place has fewer birds:  a city?  or a cornfield?

When birders visit cities they often think, “There are no birds here.”  This isn’t accurate, but I think so too until I realize there’s a very high quantity of birds but low quality — lots of pigeons, starlings and house sparrows.  It’s the lack of diversity that prompts the comment.

Bird diversity is highest where the habitat provides a wide variety of food, cover and nesting sites.  A 20-year study of abandoned fields on Long Island found that bird diversity increased with the foliage height.  Since there’s not much foliage in cities the birds we find here are those who nest on or in buildings and eat human refuse or handouts — and the birds who prey on them.  (Peregrines!)

Most songbirds eat insects and invertebrates which are hard to come by in the asphalt jungle. Even hummingbirds who sip nectar feed insects to their young.  If you want birds you must have insects.

Places without insects are biological wastelands because they’re also missing everything that depends on insects, all the way up the food chain.  Here’s a picture of a wasteland.  There are no birds here.Cornfield in Penn Yan (photo by Jamie Lantzy via Wikimedia Commons)

I bet you’re thinking, “That’s not possible. There are plants in that cornfield. There have got to be insects and birds there too.”

Nope.  Today in the U.S. we use more pesticides than we did when Rachel Carson warned us about them in Silent Spring.(1)

90% of the corn we grow is genetically engineered to survive the assaults of herbicides, fungicides and insecticides.  This allows cornfields to be sprayed frequently(2) without hurting the corn.   Seed is also pre-treated with insecticide.

There are no insects in cornfields, no birds, and no plants except corn.  I was amazed when I found out about this at Cornstalks Everywhere But Nothing Else, Not even a Bee.

Not even a bee.  Hmmmm…

 

(credits: photo of Pittsburgh from the Fort Pitt Bridge and a cornfield, both from Wikimedia Commons.  Click on the images to see the originals.  Today’s Tenth Page is inspired by page 620 of Ornithology by Frank B. Gill.)

4 responses so far

Aug 06 2013

I Will Sing With You

Nightingale singing in Berlin ()photo by J. Dietrich via Wikimedia Commons

Yesterday while on my way to somewhere else , I discovered a blog called Goldbird Variations that began when the author started playing music for birds.

Years ago Lisa Rest of Chicago took up the piano again and often played with her window open.  One day a mourning dove flew to the windowsill and sang along.  She didn’t understand what it was doing until later, wanting to share her music with an audience, she rediscovered that the birds were listening outside her window and singing as she played.

Soon she began intentionally playing music for birds, recording their duets and writing about her encounters.  Now she’s hooked on birds and blogging.  I know how that is!

Lisa has perfect pitch and can tell that the birds do too.  Listen to a cardinal sing with her in this post that explains why birds are attracted to music.

Which leads to the nightingale above…

Lisa points out she’s not the only one to play music for birds.   In May 1927 the BBC recorded Beatrice Harrison playing Londonderry Air on her cello in her garden in Surrey as a nightingale sang along.  The bird waits for her phrases and blends in at appropriate times.  Amazing!  Click here to download and play the mp3 recording from the Music And Nature radio program.

I have neither perfect pitch nor musical skill but I’ve encountered birds’ interest in music when I whistle while I hike.  I’m particularly fond of Bach and Beethoven and since I don’t sing well I whistle my favorite tunes.

Their favorite of my repertoire seems to be the second movement of Beethoven’s 6th Symphony, Szene am Bach (Scene at the brook) from his Pastoral Symphony.

Of course the birds like that one!

 

(photo of a nightingale singing in Berlin.  Click on the image to see the original on Wikimedia Commons.  This post was inspired by the Goldbird Variations)

5 responses so far

Jul 31 2013

Mysterious Disappearance

House sparrow (photo by David Lofink via Wikimedia Commons)

If you live in North America this fact is amazing:  House sparrows are an endangered species in Britain.

I learned this when I read John Metcalfe’s article called Making Cities More Bird Friendly With Nesting Bricks.  In it he describes a new brick specially designed by Aaron Dunkerton and manufactured in England to provide habitat for nesting house sparrows.  Before mortar is applied it looks like this.  (Click on the bricks to read about them.)

Bird brick by Aaron Dunkerton (image from Aaron Dunkerton's website)

House sparrows are the most widely distributed wild bird on earth.  Why are they so endangered in the U.K. that people invent ways to help them?  Here’s what I found out.

Since 1977 house sparrows have declined by 71% in Britain.  In some locations they are nearly extirpated.  London’s Kensington Park had 2,603 house sparrows in 1925.  By 2000 there were only 18.

Despite many studies a single cause has not been found and no other urban/suburban bird has experienced a similar decline.

In 2005 Kate E. Vincent published a house sparrow population study.  In 2009 Lorna Margaret Shaw investigated the role of neighborhood socio-economic status in house sparrow abundance.  These studies found:

  • The greatest house sparrow declines occurred where nestlings starved within a week of hatching or had low fledging weight, both due to lack of insect prey.  The best success occurred where they ate plenty of aphids or spiders.  (Aphids come up again!)
  • Because house sparrows nest in holes in buildings, they did well in neighborhoods built before 1919, in neighborhoods where soffitt and fascia were made of wood, and in distressed neighborhoods where the buildings needed repairs.  They avoided neighborhoods built after 1985 because of new construction standards and lack of deterioration.  That’s why Aaron Dunkerton invented the bird brick for new homes.
  • House sparrows did poorly in tidy neighborhoods with lots of paving.  Over the years Britons have paved their front yards and removed trees and shrubs so they can park their cars.  This has reduced house sparrow habitat.
  • All habitat was not equal.  House sparrows preferred deciduous plants and the insects associated with them.
  • House sparrows did not use ornamentals or evergreens.  This lead to a headline that Leylandii hedges were to blame for the house sparrow decline.  (A fascinating topic…more on that tomorrow.)

With so many factors in play there’s no simple answer to the house sparrow’s mysterious disappearance.  In the meantime they continue to decline and Britons miss them terribly.

If it would work I’d package some of ours and send them to England.  We have a house sparrow surplus right now.

 

(photo of a house sparrow in California from Wikimedia Commons. Nesting bricks by Aaron Dunkerton.  Click on the images to see their originals.)

7 responses so far

Jul 29 2013

Will They Kill 3,600 Barred Owls?

Barred Owl (photo by Chuck Tague)

A troubling plan slipped under the radar of Easterners who care about barred owls and native birds.

In the Pacific Northwest, northern spotted owls have been listed as threatened since 1990 under the Endangered Species Act.  The number one cause for their decline is the logging of old-growth forest.  The logging stopped in the national forests in 1991 but the spotted owl continues to decline, especially in smaller forest tracts.

Barred owls are distant relatives of the northern spotted owl.  They formerly lived only east of the Great Plains but for 100 years they have slowly spread north and west and now inhabit the Pacific Northwest as well.

In recent years biologists studying spotted owls noticed the spotteds declined in zones where barreds increased, so U.S. Fish and Wildlife Service has proposed killing barred owls as an experiment to see if this helps the northern spotted owl.

The proposal, published in March 2012 as a Draft Environmental Impact Statement, included a public comment period.  We may not have noticed the proposal but westerners saw and commented.

The comments were overwhelmingly negative from “Don’t do it!” to “This is stupid!” to an excellent letter by biologist Elizabeth Ellis who has studied northern spotted owl populations and pointed out the flaws in the proposal including the lack of barred owl population studies (it is threatened in parts of its range!), unknown human contribution — if any — to the barred owl’s range movement, the fact that the proposal tracts where barred owls have gained a foothold are known to be too small to adequately protect the northern spotted owl, and the wisdom of using limited management funds to kill an unstudied species.

If I’d had a chance to comment I would have said…  (stepping up on my soapbox)…

Humans directly caused the disappearance of 90% of the Pacific Northwest old growth forest. When species are going extinct because of our actions we have a choice:  Do we cut down the last 10% of the forest or stop logging?  We can control the things that humans do, however…

We cannot control the rest of Nature.  Humans did not actively introduce the barred owl.  We don’t fully know why it arrived.  It is hubris to think we can control what’s happening by killing it.

The barred owl is so closely related to the northern spotted owl that the two can interbreed. The barred owl may be adding strong genes that the spotted owls need to survive.  Interbreeding is anathema to species purists but it’s how nature works.  Would we cull blue-winged warblers because they interbreed with and seem to out-compete the less abundant golden-winged warbler?  Culling native birds to protect a favorite species is a dangerous precedent.

The Pacific Northwest is not an isolated island so barred owls will continue to naturally arrive in the northern spotted owl’s territory.  If the proposed experiment works the culling will have to continue as long as humans have the stomach and the money to do it.

I could go on and on…

At this point it is up to U.S. Fish and Wildlife Service to decide whether to go forward with their plan.  I hope they drop it like a hot potato!

(stepping down from my soapbox…)

Thanks for listening.

Click here for information from the U.S. Fish and Wildlife website on their plan to kill 3,600 barred owls in the Pacific Northwest.

(barred owl in Florida, photo by Chuck Tague)

10 responses so far

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