Yearly Archives: 2010

Heron Sunrise

Nesting & Courtship, Water and Shore
Great blue herons' nest at sunrise (photo by Chuck Tague)
Great blue herons’ nest at sunrise (photo by Chuck Tague)

Great blue herons are very large birds.  They’re four feet tall with a six-foot wingspan and weigh over five pounds, yet they nest in rookeries high in the trees.

The nest is the focus of their family life.  Because they are seasonally monogamous, their first order of business when they return in the spring is to attract and court a mate.  They do this at the nest with elaborate courtship displays initiated by the male.

Before he has a mate he circles the rookery in exaggerated, laborious flight, then lands with his head and neck plumes erect and croaks his Landing Call.  On the nest he does the Stretch Display, extending his neck and raising his bill to show off his beautiful throat plumes, then lowering his head and moaning.

He preens his wing.  He fluffs his neck.  He raises his crest.  He grabs a twig on the tree and gives it a shake.

He does his utmost to get noticed!

When a female heron agrees to be his mate their displays become elaborate duets.

In the Greeting Ceremony a heron returning to the nest where his mate is waiting will give the Landing Call while his mate does the Stretch Display.

The Stick Transfer ceremony is an exaggerated drama of nest building.  The male arrives with a stick for the nest.  The female does the Stretch Display and takes the stick while he rapidly claps the tip of his bill at her.  Then she places the stick on the nest.  Ta dah!

They even have a ceremony for Nest Relief.  The arriving heron gives the Landing Call, his mate on the nest does a Stretch Display, then they both clap the tips of their bills and sometimes preen.

If you watch at a heron rookery you’re most likely to see these displays at dawn or dusk because the females leave the area during the middle of the day.

So plan your next adventure for early morning and have a heron sunrise.

(photo of nesting great blue herons in Florida by Chuck Tague)

p.s. Click on the imbedded links above for photos of the courtship displays or click here for a photo sequence.

Heron Rookery

Nesting & Courtship, Water and Shore
Great Blue Heron rookery in sycamores (photo by Tim Vechter)

23 March 2010

Have you ever seen a tree that looks like this with a lot of big nests in it?  Surrounded by trees with similar nests?  If you’re in southwestern Pennsylvania, you’ve found a great blue heron rookery.

Great blue herons nest colonially near creeks, rivers, lakes and wetlands.  Their group of nests is called a rookery after the colonial nests of the Eurasian rook, a common bird like our crow that’s called a “rook” because of the sound he makes.

Great blue heron rookeries are large, often containing several hundred nests that are used year after year.  In Pennsylvania they’re usually located in sycamores in an isolated place on an island or in a wooded swamp.  The location is chosen for its access to food and isolation from predators, but food doesn’t need to be right there.  Adult herons will commute nine miles on foraging missions, so the heron you see hunting koi in your backyard pond may well have flown a long distance to get food for his kids.

In March the great blue herons return to Pennsylvania to set up housekeeping.  Even from a distance you can see them standing on the old nests making home improvements, a twig here, a stick there. They also do elaborate courtship displays on the nest including stretching, bill snapping and a crest raising display.  They look too large to use the nests, but I’ll show you how they do it in tomorrow’s blog.

If you have the chance now’s the time to notice heron rookeries, for in six short weeks they’ll be hidden.  The trees will be covered in leaves by May.

And remember, if you find a rookery don’t disturb the birds.  They’ve chosen the site because it’s isolated from predators, including humans.  Herons will abandon a rookery where the disturbance becomes too great.

(photo by Tim Vechter)

Dorothy surprised me

Peregrines


For the first time ever Dorothy, the female peregrine at the University of Pittsburgh, has laid five eggs.  This is her ninth nesting year and she’s always laid four eggs, so there was no reason to expect she’d lay a fifth this afternoon.  But there it is.

E2 ‘s going to have his work cut out for him when it’s time to feed them!

(photo from the National Aviary snapshot camera at University of Pittsburgh)

Thoughts of Love

Bird Behavior, Doves & Chickens

In the spring, a young man’s fancy lightly turns to thoughts of love — Alfred Tennyson

And so it is with birds.

It’s really spring now.  The raptors are courting and laying eggs, robins are singing as they migrate home and pigeons are billing and cooing.

“Pigeons?” you say.  Pigeons are the urban peregrines’ major food source so I’m rather fascinated by them.  And they’re easy to observe.

Who hasn’t seen a male pigeon puff his throat, fan his tail and coo and strut circles around his lady?  Sometimes he drives her (chases) to separate her from the other males.  This seems promiscuous, but pigeons mate for life.  They’re just doing the ritual to “get in the mood.”

Mated pairs also preen each other in courtship and like many birds the male feeds his mate.  Columbids feed their young by regurgitation, so they touch bills to offer food.  When you see pigeons billing and cooing, the male is demonstrating he’s a good provider.

Pigeons also have a courtship flight display that makes a noise.  The male flies out, clapping his wings three to five times on the upstroke (yes, he smacks the upper side of his wings together) and then glides with his wings in a V.

Birds of North America says this wing-clapping is usually a post-copulatory display.

I’m hearing it a lot lately.  Yes, the pigeons have turned to thoughts of love.

 

(photo by Aomorikuma via Wikimedia Commons, GNU Free License)

Streaming Webcams update

Books & Events

If you’ve been having trouble seeing the National Aviary’s streaming webcams, here are some technical tips on what to do.

  • If you used to be able to see the stream but now see a big, white, spinning circle or no video at all:  This means your computer thinks it’s connected to the stream but it it isn’t.  To set it straight, close all your browser windows.  Then open one browser window — !do not go to the webcam pages yet! — and empty cache.  To empty cache in Internet Explorer 8, choose Tools > Internet Options > [Delete] browsing history.   To really convince your computer to behave, reboot it, empty cache and don’t view either of the streaming videos until your computer has been running for about 5 minutes.
  • Chat problems:
    • Chat does not work on the Gulf Tower webpage.  You can sign in but you’ll see nothing.
    • If you sign into Gulf Tower chat it may confuse your computer.  Close your browser windows and reopen.  Only sign in to Cathedral of Learning chat.
  • If you’re having problems all the time:
    • Wildearth has learned that Firefox’s update 3.6 does not work with their web pages.  NOTE ON MARCH 23:  Firefox 3.6.2 does work.  If your Firefox is not on that version, you’ll need to update it
    • If you don’t have java enabled on your computer, you won’t be able to see the streams.
  • AUDIO WITH NO VIDEO was fixed (we hope) on March 24:  If you can hear the audio and see the ads but have no video, then empty your browser’s cache and reload the page.  In Internet Explorer 8, choose Tools > Internet Options > [Delete] browsing history.

If your problems persist after this Wednesday, please leave a comment here and I will forward it to the National Aviary or you can contact them yourself.

2 Eggs at Gulf Tower, 4 at Pitt

Peregrines

Reporting egg counts is like reporting hockey scores, except the action is a lot slower.

First, a picture of Tasha this morning at 6:40am with two eggs (pink arrow is pointing to them).  She laid the second one yesterday and spent a lot of time calling last night … or was that Louie making all the racket (see below).  Who knows why!

When I tuned in this morning, she called again and I heard Louie answer from somewhere in the background.  Then she left the nest.  I’ll bet he brought her breakfast.

 

Next, is a photo showing Dorothy and E2 bowing over their four eggs at The Cathedral of Learning this morning at 9:00am.  He was incubating while she ate.  Now she’s returning to take over nest duty.

Back at the Gulf Tower, here’s a photo of Louie calling to Tasha to come to the nest at 10:10am today.  I learned from Ann Hohn that Louie often sits in and around the nest and “he is VERY noisy. He calls for her all the time.”

And a CORRECTION!  On Saturday night I said the following video was Louie & Tasha courting at the nest.  I was wrong.  It’s a video of Louie and his new mate, Dori, at the nest at 6:55pm Saturday, March 20.  PixController made it into a YouTube video.  Click here to watch.

(photos from the National Aviary webcams at the Gulf Tower and University of Pittsburgh)

Anatomy: Throat

Bird Anatomy

It’s been “All Peregrines, All The Time” for the past week but for those of you following the anatomy lessons, never fear.  The series continues every Friday (barring a peregrine “emergency”) because I haven’t gotten halfway through the bird yet.

We’ve just reached the underside where the body part names are often the same ones we use to describe our own anatomy, so you’re going to have an easy time of it for a while.  Stay with me, though.  It will get interesting later on.

First up is the throat and the best bird to illustrate this is a male ruby-throated hummingbird.  Just in case you’re wondering where his throat is I’ve pointed to it with a pink arrow.

The throats on female ruby-throated hummingbirds are white.  The males have iridescent red feathers which only look this red when the light catches them just right — and then they’re so red they knocks your socks off.

Yes, the throat on a bird is where you’d expect it to be.

(photo by Marcy Cunkelman)

Wilmington: Is the Fighting Over?

Peregrines


Three days ago, viewers of the Wilmington, Delaware falconcam were shocked to see two male peregrines locked in combat on the nest.  The fight lasted more than an hour and in the end the vanquished left and the victor paced the gravel with a white feather and blood from the loser’s breast on his beak. 

What now?

An hour later the resident male peregrine visited the nest and calmly surveyed the scene.  He had won the battle, but his long-time mate was dead and the new female who challenged her was claiming the nest as her own. 

This peregrine nest at the Brandywine Building in Wilmington, Delaware has seen more than enough trouble in the past year.  Last May, two peregrine chicks were found dead and the other two leapt or were carried from the nest, though still unable to fly.  One chick was rescued and placed back in the nest only to disappear a few days later.  No young survived.

What danger would prompt the young to leap?  What would kill them without eating them?  Around that time, a second female peregrine had arrived and was harrassing the resident female.  On rare occasions an intruder will invade the nest and kill her rival’s young.  Is that what happened here?  No one knows because there was no webcam. 

But this year there is a webcam, installed by the Delmarva Ornithological Society, and it has already helped solve the mystery of the fight for this nest.  At the end of Monday’s fight, we knew the resident male had won — for now.

Is the fighting over?  Will the resident male and the new female peregrine be able to raise a family in peace?  We don’t know, but the webcam will help us find out.  Click on the photo above to visit the Wilmington falconcam.

In the meantime, see slides of Monday’s fight and read about it on Kim Steininger’s Wilmington Falcons blog.  Her March 15th entry includes a link to a 21-minute video of the fight. 

And don’t miss the rest of Kim’s Wilmington Falcons website.  You’ll really enjoy her photos!

(photo from the Delmarva Ornithological Society webcam at the Wilmington, Delaware peregrine nest)

First peregrine egg at Gulf Tower, 3 at Pitt

Peregrines

We had lots of action at the Pittsburgh peregrine nests overnight.

Tasha at the Gulf Tower laid her first egg of 2010.  Click on her photo above to see a nighttime image of her with the egg, captured by Marianne Atkinson before 5:00am.  As Marianne watched, Tasha carefully moved the egg to the right and into the scrape.  In the nighttime image, the egg is the white circle and Tasha is bending her head down with her tail in the air.

Meanwhile at the Cathedral of Learning, Dorothy laid her third egg as shown below.  

The eggs are white in nighttime pictures because they’re made visible using infrared light.  In daylight the eggs are a deep red-brown color.  Yes, that’s the egg between Tasha’s feet.  

So why do Dorothy’s eggs look pink on the streaming cam at Pitt?  Because the infrared light is very close and the camera can see infrared, even during the day. 

Don’t miss the action!

  • Watch the Gulf Tower streaming camera here,
  • The Cathedral of Learning streaming camera here, and
  • The snapshot cam at the Cathedral of Learning here.

Now that Dorothy has laid her third egg she will likely begin incubation.  See the Peregrine FAQs for more information.

(photos from the National Aviary webcams)

Urban Kestrels, New York

Birds of Prey


I think of kestrels as rural birds because I often see them perched on wires above fields.  In fact, they’re cavity nesters so if they find a good hole to nest in and plenty of food they’ll set up shop anywhere that affords them a long sight line to the next meal.

American kestrels are our smallest falcon, only the size of robins, and they capture small prey: grasshoppers, mice and small birds.  This earned them the nickname Sparrow Hawk so I shouldn’t be surprised that they hang out in cities where there are plenty of house sparrows.  In our biggest city?  Yes, kestrels nest in New York.

For many years a small group of dedicated New Yorkers has been studying the city’s kestrels and keeping tabs on their nests.  Three years ago they realized the task was too big for them alone so they published a poster (Have You Seen This Bird? in 14 languages!) and “Birding Bob” DeCandido began emailing a Kestrel newsletter.  The group has grown as people discover kestrels, begin monitoring their nests, and rescue the fledglings who land in unsafe places. 

Monitoring kestrel nests can be fun.  The birds often choose nest sites in the damaged cornices of old buildings.  What a surprise when they poke their heads out of the holes!  The challenge comes when the young fledge and land on the street.  Fortunately people rescue the birds and they get excellent rehab care.  I was hooked when I read Jim O’Brien’s blog about the release of the rescued kestrels in Central Park last June.  Too bad I don’t live in New York.  I’d have been there!

Overall, American kestrels seem to be doing well but the count of kestrels at eastern hawk watches has declined for the past 20 years.  This is worrisome, so anything we can do to help kestrels is a plus.  Thanks to these folks — Robert DeCandido, Jim O’Brien, Deborah Allen, Bobby Horvath, Cathy St. Claire, Chad Seewagen and K.A. Peltomaa — and to those who’ve learned from them, New York City’s kestrels may be the most successful breeding population on the East Coast.

If you live in New York and want to help, click on the poster link above for more information or contact Robert DeCandido 718-828-8262 (rdcny<AT>earthlink.net), Jim O’Brien (YoJimBot<AT>gmail.com) or Deborah Allen (DAllenyc<AT>earthlink.net).   Just change the <AT> to an @ sign to send them email.

.

p.s.  I love how this urban kestrel is perched on a wire… razor wire.

(photo by Robert DeCandido, PhD)