Monthly Archives: August 2010

Anatomy: Mandible


Last week I used a term I hadn’t defined yet.

Mandible means jaw and comes from the Latin mandere which means to chew.  In mammals the mandible refers only to the lower jaw but in birds it’s the name for the two parts of the beak, upper and lower. 

The best bird to illustrate this is the black skimmer who has very large mandibles for his size.  Related to terns, this bird lives at the coast and feeds on small fish near the surface of the water. 

His beak is his fishing tool.  Not only is it huge and colorful but if you look closely at this picture you’ll see that his lower mandible is much longer than the upper. 

To catch fish the black skimmer flies just above the water dragging his lower mandible in the sea.  When a minnow is caught in his beak, he snaps his bill shut and swallows. 

The technique looks like skimming, hence his name.  Click here to see what he looks like when he’s fishing.

(photo by Steve Gosser)

Dorothy at Dusk


Back in June when the peregrine fledglings had just flown at the University of Pittsburgh, Steve Valasek saw Dorothy perched on one of the 32nd floor spouts at the Cathedral of Learning.

He went inside and took this picture from the 36th floor window.  It gives you an idea of the peregrines’ perspective.  So high up. 

Night was falling and the lights were coming on.

Dorothy at dusk.

(photo by Steve Valasek)

Many Cicadas

Annual Cicada (Neotibicen linnei) — photo by Bruce Marlin from Wikimedia Commons

I’m sure you’ve heard them.  This summer the cicadas in Pittsburgh are especially loud and are singing all day.  They’re so loud that it sounds like we have an extra brood this year.

The ones we normally hear at dusk are Scissor-grinder Cicadas, so-called because of their sound.  This year we also have Linne’s cicadas, pictured above, who sing during the day.  Both of these bugs fall into the general group called “annual cicadas” even though most species live more than one year — typically two to ten.

Cicadas spend the majority of their lives underground in the larval stage.  Then in the summer of their adulthood they emerge from the ground, mate and die.  Some years the differently aged groups happen to reach maturity at the same time.  For instance the 10-year bugs and the 2-year bugs could emerge during the same summer of the tenth year.

Perhaps 2010 is one of those years when Linne’s and the Scissor-grinders happen to coincide.  At any rate, I know we aren’t hearing from the 17-year cicadas.  The Magicicadas last appeared in 1999 and won’t emerge in Pittsburgh again until 2016.

Magicicadas spend 16 years underground and emerge as an overwhelming population in their 17th year.  They are large, loud bugs with bright orange eyes whose chorus is so loud it’s almost deafening.  They look scary but are basically harmless.  All they want to do is mate so they don’t pay attention to anything except each other.

There are many more species of cicadas and they all make different sounds.  I learned a lot about them on Chuck Tague’s swamp cicada blog and at the Songs of Insects website.

So, no, these aren’t Magicicadas.  We’ll have to wait six more years for the Magic to begin.

 

(photo by Bruce Marlin from Wikimedia Commons, Creative Commons license.  Click on the photo to see the original.)

p.s. Here are two more recordings of cicadas occurring in western PA:  Lyric cicadas and and Dog-day cicadas

Among the Tombs

Last week I got an excited voicemail from a friend.

Jay Volk and his wife were in Homewood Cemetery looking at the biggest bird they’d seen in a long time – and it was screaming.  They drove past it in their car while Jay’s wife recorded this video with his cell phone.

Right there on the Roberts’ tombstone is a juvenile red-tailed hawk.  How can I tell?  Because the bird is too young to realize it should be upset by the people filming it and because its voice is a whining, begging call.

If you look closely at the tombstone at the far left you’ll see the back of a second juvenile red-tail facing away.  This is probably a sibling and you can hear it begging too at the end of the video.

I’ll bet these two fledged from a nest in the cemetery.  They’re certainly doing what juvenile birds do best:  Waiting and calling for their dinner.

(video from Jay Volk)

Another Quiz


Marcy sent me several mystery birds.  Here’s one that’s been a regular visitor to her feeders during the month of July. 

Do you know what bird this is?  Here are some hints:

  • Stripe-y.  Note whether the stripes are narrow or wide.
  • Bill shape
  • At the feeder
  • Just a little splash of color. Note what color it is and where.
  • Big hint: This bird shouldn’t be here now.

What do you think?

(photo by Marcy Cunkelman)

Mystery No More


A week ago this flower had me stumped when I found it at State Gamelands 95 in Butler County. 

The plant is six feet tall and has big, lobed, alternate leaves, but how to describe the flower?  It looks like it never opens.  Nonetheless I posted my vague description of it on PABIRDS and hoped someone would enlighten me.

My description must have been adequate because at least five people responded and all of them said, “It’s Pale Indian Plantain, Arnoglossum atriplicifolium (L.) H. Rob.

In case you come across it and are stumped too, this is what it looks like. 

But one photo isn’t enough.  The picture above is a closeup of the flower umbel by Marcy Cunkelman.  Click here for a view of the entire plant by Dianne Machesney.

Now you know.

(photos by Marcy Cunkelman and Dianne Machesney)

It’s Goldfinch Time


Everyone’s remarking on how beautiful the goldfinches are this year with their bright yellow bodies, black wings and black caps.

American goldfinches are very active right now because they’re nesting.  They live on seeds and don’t have hands so they use their crops to carry food to their babies in the nest.  Both parents feed their young through regurgitation. 

Keep your thistle feeder full and the goldfinches will wait in line.

(photo by Marcy Cunkelman)

Anatomy: Beaks

The shape of a bird’s beak matches its lifestyle.

  • Raptors have sharp, hooked beaks for tearing meat.
  • Crossbill beaks have crossed tips so they can pull seeds easily out of pine cones.
  • Avocets have long, thin, upturned bills because they skim the water with their lower mandibles to capture aquatic food.
  • Conversely, flamingos have wide downturned bills because they sweep the water with their upper mandibles.  They turn their heads upside down to eat.

Why do ducks have long bills with serrated edges?  Why do woodpeckers have pointy beaks?  Why do pelicans have pouches?

The answers are easy if you know something about their lifestyles and what they eat. 

See if you can figure out the reasons for the rest of the beak shapes shown above. 

Keep in mind the illlustration is fanciful.  Our spoonbills don’t have orange-brown heads and our buntings don’t have yellow eyes and bills. 

(Frankly I couldn’t refrain from changing the title of the bunting picture.  It was originally labeled “night hawk” but the beak shape is so unlike a common nighthawk’s that I couldn’t stand it.)

(image from www.infovisual.info. The name “night hawk” was altered to “bunting.”  Click on the image to see the original.)

The Tyrant


The king of the Tyrant flycatchers, Tyrannus tyrannus, has earned his name for his fierce attacks on predators that are many times his size.

Otherwise called the eastern kingbird, he lives in open areas, eats flying insects and is very aggressive.  Not only does he defend his nest from other kingbirds but he relentlessly attacks blue jays, crows and hawks who wander into his territory — even to the point of riding on the back of a hawk so he can peck its head. 

Don’t believe it?  Check out this story and photo from Illinois and this photo sequence on Flickr by Arlene Koziol.

After you’ve seen the Illinois photo you might wonder why the top of the kingbird’s head looks orange-red.  Well, he’s excited.  Eastern kingbirds have a splash of orange-red feathers on the crown of their heads that’s normally hidden.  When they’re excited they raise their head feathers and we all see red.

Woe be to the red-tailed hawk who gets in the tyrant’s way!

(photo by Steve Gosser)