Monthly Archives: July 2011

Shouting Above the Din

Song is an important territorial and mate-attraction signal for birds so how do they cope when there's a lot of noise?

Many songbirds abandon noisy settings but some can handle it by changing their songs.

Dr. Clinton Francis of the National Evolutionary Synthesis Center in Durham, NC studied two species of western vireos in noisy areas and found that both altered their songs so they could be heard. 

Gray vireos (Vireo vicinior) sang longer songs and raised the pitch of their highest notes while plumbeous vireos (Vireo plumbeus) sang shorter songs and raised the pitch of their lowest notes.

Where do these birds live that it's so noisy?  Near natural gas compressor stations in rural New Mexico.   The compressors roar non-stop at more than 95 decibels. 

Pennsylvania has a lot of compressor stations in Marcellus Shale drilling areas.  Maybe Dr. Francis will study our birds.

Read more here in Science Daily.

And here's a similar study done in Colorado.

(photo by Clinton Francis of the National Evolutionary Synthesis Center, linked from the Science Daily article)

Cool Water

Here's a place that's changed for the better in the last 200 years.

Hells Hollow Falls are part of the gorge cut by Hell Run, a tributary of Slippery Rock Creek in Lawrence County. 

At its headwaters Hell Run flows through farmland, then into the woods where the gorge and waterfall have been protected as part of McConnell's Mill State Park.

It wasn't always this beautiful.

In the mid-1800's the valley was logged and mined for its iron-ore-rich limestone and the coal to fire its industry.  The Lawrence Iron Furnace, two coal mines, a quarry, and a lime kiln were all within a short walk of the waterfall.  It must have been a smoky, dirty place in those days.

In the 1870's the local iron business collapsed and within 50 years the coal mines closed too.  The trees grew back, the buildings disappeared, and the brick-walled lime kiln became a curiosity in the woods. 

The only noticeable scar is coal mining's affect on the water.  The abandoned mines release toxic, orange, acid mine drainage (AMD) into Hell Run's feeder streams above the falls.  Fortunately, even in the dry month of July there's enough fresh water to dilute it. 

When I visited Hells Hollow Falls last Sunday I marveled at the miniature slot canyon upstream.  Geologists say this channel was formed when the creek ran inside a limestone cave just below ground level.  Eventually the top of the cave fell in and revealed the flume, pictured below.  If I was the size of an ant, this would be the Grand Canyon.

If you'd like to see these wonders for yourself, click these links for information on Hells Hollow and McConnell's Mill State Park.

The waterfall looks cool ... especially in this heat.

(photos by Kate St. John, taken on 17 July 2011)

Teasel Time

This spiny flower is blooming now.  If you look closely you'll see that its tiny pinkish-purple flowers are quite pretty. 

But it's hard to get close.  Teasel (Dipsacus fullonum or Dipsacus sylvestris) looks like a warning.  Its prickly stem, spiny flower head, and slender thorny spikes seem to shout "Stay away!"  

Interestingly, the only reason this plant is here in North America is that its spiny heads were used by the textile industry.  After the flowers fade and the plant dries out the heads can be used to raise or "tease" the nap on woven wool.  

Factories substituted metal brushes for teasel long ago but the plant persists in our landscape.  It's now invasive in thirteen states, though not in Pennsylvania. 

Look for it by roadsides and in waste places.  Each plant can produce 2,000 seeds so where there's one teasel there will soon be more!

(photo by Dianne Machesney)

Avian Architecture

I've just finished reading a fascinating book about birds' nests called Avian Architecture: How Birds Design, Engineer & Build (Princeton University Press, 2011) by Peter Goodfellow.

It's not your typical bird-nest guide.  Instead the book groups nests by architectural type, shows blueprints of their construction, and provides case studies and photographs of species who construct each type. 

Did you know that...

  • Female hornbills seal themselves into their cavity nests and must rely on their mates to feed them through a narrow slit until the chicks are ready to fledge.
  • African Jacanas build nests that float.
  • Spider silk and moss work like Velcro.  The builder can stick them together, pull them apart and re-glue them elsewhere.  Hummingbirds are masters at this.
  • Some birds actually stitch their nests.  The common tailorbird (nest pictured above) wraps a large leaf with a thread to make it curl, then pokes its bill through the leaf edges and uses spider or cocoon silk to sew it in place.  When the curl is secure she builds her nest inside.
  • Megapodes build compost heaps and lay their eggs in them.  The heat of the decaying vegetable matter incubates the eggs.

If you'd like to learn about avian architecture this book is a great place to start.  The photographs and illustrations are gorgeous.  I learned something new on every page.  

Click here to find out more from Princeton University Press.

(photo of a Common Tailorbird nest by J.M. Garg at Wikimedia Commons.  Click on the photo to see the original.)

p.s.  Scott Shalaway recommended this book among his Wildlife Books for Summer Reading.

The Lesser One

If you've never been to the southwest or California, you've probably never seen this dainty little bird. 

Smaller than the American goldfinch, this one is called the lesser goldfinch

Lesser goldfinches look slightly different from the Salad Birds I wrote about on Friday.  The males have black backs in Texas, green backs in the rest of their range. 

Their food preferences are slightly different too.   In addition to seeds, lesser goldfinches eat buds, flowers and fruits.

Flowers?   Yes, they'll eat the flowers of chaparral honeysuckle and three species of oaks.  They've even been known to visit hummingbird feeders, though not as a steady diet.

So I guess the lesser goldfinch can't earn the nickname "Salad Bird."  Perhaps he's a "Flower Child."    😉

(photo by Julie L. Brown.  Click on the photo to see the original.)

Threat Display

This dragonfly doesn't perch like this for fun.  His pose is a threat display.

This is a male Common Whitetail (Plathemis lydia), a showy dragonfly with a white pruinose abdomen and clear black-striped wings. 

Common Whitetail males are highly territorial.  They live near ponds, marshes and slow moving rivers where they defend 10 to 30 yards of the water's edge and conspicuously chase away all other males.  When they're not chasing they pose like this to let the others know they mean business. 

Their white pruinose backs are the warning sign.  Pruinose refers to the dusty, frosted appearance caused by a pigment that covers the insect's "skin."  In nature, pale-colored pruinescence often reflects ultraviolet light.  If so, this bug probably glows in sunlight.  I wish I could see it!

Female Common Whitetails look quite different because their tails aren't white, a feature that probably protects them from male aggression. 

Watch near water and you'll see the males patrolling.  Try to find the females too, even though they're not so flashy.  

I'm happy when I see them.  These dragonflies eat flying insects, including mosquitoes!

(photo by Chuck Tague)

Salad Birds

American goldfinches have a lot of nicknames: wild canary, yellowbird, thistle bird and salad bird. 

I'd never heard of "salad birds" until Matt Sharp told this story on PABIRDS last month. 

Matt remarked, "My father has a small vegetable garden and for the last couple years around this time of the season, goldfinch, usually in pairs, attack a couple types of leafy greens. The main item is Swiss chard, but they also seem to like beet greens, and to a lesser degree lettuce (romaine or similar with red pigments and not the green varieties like iceberg). He has observed them eating the chard, biting pieces of leaf, but only seen indirect signs of feeding on the lettuce and beet greens (little beak shaped bites around the leaf edge).  So it seems that the birds are definitely eating the plant, and not preying on insects or collecting material."

Rudy Keller replied, "This behavior is so common that it accounts for one of the Pennsylvania Dutch folk names for goldfinch -- the salad bird."

American goldfinches are vegetarians.  They're especially fond of seeds but in the spring they'll also eat buds and strip the bark from terminal shoots.  They've been known to eat green algae, maple sap, and as Matt pointed out salad greens.  They rarely eat insects and then only if the insect happens to be in the beakful of food they're actually seeking.

This food preference protects them from brown-headed cowbirds who lay their eggs in songbird nests.  The cowbird chicks usually dominate the host's nest and the songbird's babies die.  But cowbird chicks fail to survive in goldfinch nests.  They starve on the vegetarian diet.

July is nesting time for goldfinches.  While other songbirds have fledglings or even second broods, goldfinches have just begun to nest.  This timing puts their hungry nestlings in synch with maximum seed production in mid to late summer. 

This month you'll see male goldfinches but not many females.  The ladies are busy incubating, waiting on the nest for their mates to come feed them. 

Perhaps a male goldfinch will visit your vegetable garden to find a treat for his mate. 

It's salad time!

(photo by Chuck Tague)

The Cranberry of Commerce

That's the description in my Newcomb's Wildflower Guide.

Various species of cranberries grow in northern climates around the world but the berries are so tart that they weren't popular as food until European settlers learned about them from Native Americans.

This plant, Large Cranberry (Vaccinium macrocarpon), is the one that's cultivated.

The shape of the flower gave cranberries their name.  The petals curl backward and the long stamens touch in front like a shooting star but if you look at the stem, flower and stamens as a whole, they resemble the neck, head and beak of a crane.   Crane-berry.  Cranberry.  

These evergreen plants bloom in acidic bogs in summer and show off their bright red berries in fall. 

Dianne Machesney photographed this one near Ricketts Glen in early July.

(photo by Dianne Machesney)

Peregrine News, mid-July

So far it's been an eventful summer for Pittsburgh's young peregrines.  Here's the latest news.

Yesterday morning Karen Lang saw the entire Pitt peregrine family near the Cathedral of Learning.  Dorothy and E2 fledged four youngsters this spring but they are now down to two:  the young male and one of his three sisters.   I believe only one sister remains because Yellow died July 4 in a window kill on Henry Street and one juvenile has been missing since June 7.  

We feel lucky to see both youngsters at this point, but I'm sure it's because the male ("Red") is still recovering from the concussion he received from his July 6 window accident at Henry Street.   Dorothy and E2 bring him food which prompts his sister to hang around for a handout.   Her loud begging makes the family easy to find.

Red's injury gained him a new name.  Karen Lang calls him Henry because the biggest event in his life (so far) occurred on Henry Street.   Fortunately the accident was not too serious and Henry's parents are helping him recover.  It will be several weeks before he's back in top condition.

Meanwhile, I just learned yesterday that one of the female youngsters at the Gulf Tower (black tape on USFW band) was injured at Macy's on July 1 and is now in rehab.  If history is any guide, she'll be there for a couple of months.

And finally, four nestlings were banded at the Monaca-East Rochester Bridge this spring -- three males, one female.  The family was present at the bridge when Mark Vass checked on them in mid-June.

No news from the other bridges ... yet.

(photo of a juvenile peregrine by Kim Steininger)

Let’s go to Sky Deck!

Bird blog and peregrine fans, let’s have a reunion!

Back in March at WQED’s peregrine event, we met a lanner falcon who was training for the National Aviary’s new Sky Deck flight show.  I promised then that we’d get together this summer to see him fly.  Now’s the time.  Let’s go to Sky Deck. 

I’ve arranged with Steve Sarro, the Aviary’s Director of Animal Programs, for a fun-filled afternoon in late August.  We’ll meet Steve at:
 The National Aviary, 700 Arch Street, Pittsburgh, PA 15212
 East Entrance on Arch Street, Concierge desk
 at 2:00 pm on Monday, August 22 (*).

He’ll give us a personal tour of the Aviary.  Then we’ll go up on the roof for the 3:30pm Sky Deck show.  It’s an open air theater where the raptors fly free.  We’ll be thrilled by acrobatic black kites, a powerful martial eagle, and the lanner falcons who remind us of peregrines.  Here's a lanner on the lure (which resembles a bird) at Sky Deck in June.

The cost is:

  • Members of the National Aviary: $5 per person for Sky Deck
  • Non-members: $18 per person (includes $13 admission + $5 Sky Deck)
  • If our group has 15 or more non-members at the Concierge Desk that day, we'll get a group rate of $9 per non-member.

Sky Deck seating is limited to 50 people so be sure to email me at if you plan to come.  We don't want to turn anyone away at the door.  (NOTE:  All Sky Deck attendees must be at least 42” tall, no babies and no strollers.)

Hope you can make it!  I’m looking forward to seeing you.

For directions and information about the National Aviary, see their website at

(photo by Chuck Tague)

p.s.  (*) Sky Deck performances require good weather.  If all day rain or severe afternoon weather is certain on August 22, we’ll go on Tuesday, August 23 instead.  Watch the blog for updates.