Archive for the 'Nesting & Courtship' Category

Feb 07 2014

Under Construction

As you saw last weekend there are still crowds of bald eagles gathered along North America’s rivers waiting for winter to end.  They can’t go home and begin courting until the ice breaks up.

Meanwhile Pittsburgh’s eagles have a head start on the nesting season because our rivers don’t freeze over.  The pair at Hays has already progressed to the finer points of nest construction.  They finished the foundation (large sticks) and the bowl (small sticks) and are now working on the nest lining (soft grasses).  Sometimes they bring a fish and have a snack at the nest.  When the lining is complete, egg-laying won’t be far away.

When you watch the Pittsburgh Hays eaglecam you’ll notice how different eagles’ habits are from peregrines’ behavior.  Peregrines don’t “build” a nest, they never use sticks or soft grasses, and they almost never eat at the nest unless they have young in it. This difference is driven by their food and habitat needs:  bald eagles eat fish and nest in trees near water, peregrines hunt birds on the wing and nest on cliff ledges.

Bald eagles also nest earlier than peregrines so watch the Pittsburgh Hays eaglecam for live updates.  If you miss the action, browse the archives here.

 

(bald eaglecam video by PixController, streaming provided by WildEarth)

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Dec 20 2013

Penguins As Far As The Eye Can See

King penguin colony on Salisbury Plain, South Georgia (photo from Wikimedia Commons)

This week I read about colonial nesting in Ornithology by Frank B. Gill.  “About 13% of bird species, including most seabirds, nest in colonies.  Colonial nesting evolves in response to a combination of two environmental conditions: (1) a shortage of nesting sites that are safe from predators and (2) abundant or unpredictable food that is distant from safe nest sites.”

The book mentions king penguin colonies; sometimes they’re huge.  This one is on the Salisbury Plain of South Georgia, an island in a volcanic ridge that arcs from the southern tip of South America to the northern tip of Antarctica.  (Click here to see where it is on Google Maps.)

There are lots of king penguins in the photo above, but zoom out below and the number is stunning.  Half a million king penguins in one place!

King Penguins at Salisbury Plain, South Georgia (photo from Wikimedia Commons)

Obviously the advantages of living like this outweigh the disadvantages of occasional social strife, epidemics, or the crash of the food supply.

Imagine being in a place where there are penguins as far as the eye can see!

 

(photos from Wikimedia Commons. Click on the images to see the originals. Today’s Tenth Page is inspired by page 330 of Ornithology by Frank B. Gill.)

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Jul 05 2013

Large Broods Wear Us Out

Common kestrel nest in Germany (photo from Wikimedia Commons)

Any parent can tell you that raising kids is hard work and even harder if there are multiple infants the same age. (Think triplets!)

Most birds experience this multiple effect every time they nest.  In fact, the work is so exhausting that having “extra” kids beyond their normal clutch size decreases the parents’ life expectancy in some species.

This was shown in studies of common kestrels in Europe in the 1980s.

A team led by Cor Dijkstra artificially lowered and raised brood sizes of common kestrels by removing eggs from some nests and adding them to others.  Kestrel parents whose brood size of five remained normal or was reduced to three experienced the typical winter mortality of 29%.  On the flip side, adults whose broods were augmented were much more likely to die the next winter.  60% of the kestrels who raised two extra chicks were dead by the following March.

For thousands and thousands of years the clutch size of the common kestrel has been honed by the deaths of those who raised too many.  The birds settled on the number five.  More than that can kill them!

 

(photo of common kestrel nest in Germany from Wikimedia Commons. Click on the image to see the original.
Today’s Tenth Page is inspired by page 521 of Ornithology by Frank B. Gill.
)

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Jun 28 2013

Why Here?

Peregrine about to land on the Tarentum Bridge (photo by Sean Dicer)

Why do peregrines nest on buildings and bridges instead of cliffs?

“Raptors imprint on their natal nest sites.  Consequently, they choose a similar situation several years later when they reach maturity.”(1)

This explains why they’ve chosen to nest at the Tarentum Bridge, pictured above.  The adult female, nicknamed Hope, was born on the Benjamin Harrison Bridge in Hopewell, Virginia.  That bridge is such a dangerous place to fledge that Hope was hacked in the Shenandoah Mountains, but she remembered where she was born and picked a bridge when she chose a place to nest.

There are exceptions to the natal imprint rule.  Though Dorothy’s daughter Maddy was born on the Cathedral of Learning, a 40-story Late-Gothic Revival building, she chose the I-480 Bridge in Valley View, Ohio.  I can’t think of anything less like the Cathedral of Learning than this.  (The nest is at a broken patch of concrete on the bridge support.)

Maddy's nest at the I-480 Bridge, Valley View (photo by Chad+Chris Saladin)

The exceptions have saved at least one species from extinction.

Mauritius kestrels used to nest in tree cavities but monkeys were introduced to the island and ate the eggs and young. By the 1960′s the kestrels were down to two pairs — almost extinct — when one of the pairs decided to nest on a cliff ledge where the monkeys couldn’t reach them. That nest was successful, their youngsters nested on cliffs, and the species rebounded.

The exceptions benefit the rule.

 

(photo of Hope at the Tarentum Bridge (blue structure) by Sean Dicer.  Photo of Maddy’s nest site at the I-480 Bridge at Valley View (busy highway) by Chad+Chris Saladin.
Today’s Tenth Page is inspired by and includes a quote(1) from page 444 of Ornithology by Frank B. Gill.
)

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Jun 04 2013

An Afternoon With Pittsburgh’s Eagles

It was hot and breezy last Saturday when Glenn Przyborski went down to the Great Allegheny Passage bike trail to see the bald eagles’ nest at Hays.

Glenn is a cinematographer so of course he took his camera and a really good scope.  His resulting video is a gorgeous, intimate look at the bald eagle family and their nestling who’s due to fledge near the end of this month.

Watch it on YouTube above, or see it in HD on Glenn’s Vimeo site.

(video by Glenn Przyborski, Przyborski Productions)

 

p.s.  You can tell it was hot on Saturday because the eagles are panting.

p.p.s  Glenn used a 2000mm Celestron C8 telescope to get these great close-ups!

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May 30 2013

A Day In The Life of Six Peregrines

Downtown peregrines, parents trade places, chicks watch (photo by Christopher Rolinson, StartPoint Media)

A week ago on May 23 Chris Rolinson set up his time-lapse camera at Point Park University’s Lawrence Hall to capture snapshots of the Downtown peregrines.  My favorite is this one of Dori leaving the nest and Louie coming in.  Awesome wing action!  Look at the chicks watch and call.

Chris also created a video from the time-lapse snapshots.  Click on the photo to watch a quick day in the life of six peregrines.

Today the youngsters are all brown with a full set of flight feathers and they’re ready to fly.  Visit Third Ave Downtown to watch.

(photos and video by Christopher Rolinson of Point Park University and StartPoint Media)

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May 28 2013

This Is The Week!

dori on the balcony (photo by Matthew Richardson)

This is the week that the Downtown peregrine chicks will fly for the first time.  Right now their parents are protective while the “kids” exercise their wings.

Above, Dori paid a visit to Matthew Richardson’s balcony at Point Park’s Lawrence Hall last Thursday.

Matthew carefully checked that no peregrines were in view when he went out on the balcony with a friend, but soon Dori flew in from below, circled, and landed on the railing.

Fortunately she was silent.  Though she wasn’t angry and kakking, she got her point across that she wants folks to stay back from above while her kids are at this vulnerable stage.  Matthew wrote that she “did have pretty loud non-verbals!”

At the nest her four youngsters have lost their down and are flapping up a storm.  On Sunday they were clearly visible at the nest opening.  Mary DeVaughn saw two perched at the edge while Dori watched from above.

Dori watches over two nestlings ready to fledge (photo by Mary DeVaughn)

 

Stop by Third Ave Downtown to watch them fledge. Make sure they don’t become stranded on the street. Click here for directions.

This is the week! By June 7 the excitement near Point Park University will disperse as the young peregrines explore other parts of Downtown.

(Dori’s balcony photo by Matthew Richardson. Nest area photo by Mary DeVaughn)

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May 25 2013

Nesting Ended At Green Tree?

PEFA_Greentree_f_and_m_shannonthompson

The news is mixed from the Green Tree water tower peregrines.

On the one hand, their nest seems to have failed.

On May 17 and 18, Mary Jo Peden and Shannon Thompson reported that both peregrines were visible again.   If their nest had been successful the female would still be incubating eggs or brooding chicks while the male brought them food.  Instead the pair was seen mating and hanging out together.  Not a good sign for their first attempt.

On the other hand, Shannon digi-scoped photos of both birds and discovered the female is banded and the male is not.

The male, above right, demonstrated his bare legs by preening extensively.

The female, above left, posed with her right leg showing off a blue band.  This is the USFWS band that’s colored in some states or may be covered in colored tape to distinguish nest mates after they’ve fledged.

Ohio uses purple USFWS bands but I’ve seen those bands look blue in some lights.  Does this female have tape on her band?  Or is she from Ohio?

The mystery continues.

Click here for close-ups of Shannon’s photos.

(photos by Shannon Thompson)

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May 22 2013

Bridge Babies!

Neville Island I-79 Bridge (photo by Robert Stovers on Wikimedia Commons)

After three disappointing banding attempts at Pittsburgh area bridges, Dan Brauning struck peregrine gold yesterday at the I-79 Neville Island Bridge, pictured above.

Last week he and Art McMorris brought back disappointing news from Tarentum, Westinghouse and McKees Rocks:  solo abandoned eggs at Tarentum and McKees Rocks, and a single handicapped nestling with a poor prognosis at Westinghouse.

But yesterday was good.  Dan found three peregrine nestlings at the Glenfield span of the I-79 Neville Island Bridge.  The two males and one female chick are 22 days old.

Anne Marie Bosnyak and Laura Marshall monitor this site and were on the scene.  When they arrived at 9:00am they saw both adult peregrines on the bridge and hunting in the vicinity.  Around 10:00am Dan and PennDOT went under the bridge and walked the catwalk from Neville Island to Glenfield but found no peregrines.  If there were baby peregrines on the bridge why weren’t their parents defending them?

On the way back to the Neville Island side Dan checked some additional nooks.  One of the parents arrived with prey and was so stunned that humans were approaching her nest that she perched silently for a moment.   Then all hell broke loose.  Kak and attack!   The noise signaled her mate to come quickly and he joined the fray.

Both adults are banded and now their chicks are, too.  Dan was able to read the bands on the mother peregrine:  black/red 62/H born in 2010 in Canton, Ohio.  Ohio peregrine fans, this is Magnum, photographed by Jeff McDonald on New Year’s Day at Cork-Bocktown Rd.

The chicks are due to fledge on June 5 and they will need watchers!  The only reason we know of this site is because a fledgling fell in the river last year and was rescued by boaters.  Imagine if no one saw him!   Stay tuned next week for information on where to watch and when.  Earmark June 5-10!

Meanwhile in Beaver County…

After the I-79 Bridge banding, Dan met up with WCO Matt Kramer and confirmed that peregrines are not nesting at the Monaca-East Rochester Bridge as they have since 2007.  Instead they’ve moved 1.25 miles downstream to the huge railroad bridge across the Ohio at Monaca-Beaver.

Ohio River railroad bridge, Beaver, PA

I’m surprised they moved but not surprised they chose this bridge.  It’s the tallest in the area, has a long westward view down the river, and is perfect for nesting if you can stand the roar and thump of trains.  Back in March 2008 several of us witnessed a territorial battle at this bridge.

Why didn’t peregrines move here earlier?  Perhaps there wasn’t the proper substrate for making a scrape until now.

In any case, they’ve chosen an inaccessible spot near the top so their babies won’t be banded.  Sneaky!

 

(photo of Neville Island I-79 Bridge from Wikimedia Commons. Photo of Monaca-Beaver railroad bridge by Kate St. John)

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May 20 2013

Save The Date: Pitt Peregrine Fledge Watch

Schenley Plaza tent (photo by Kate St. John)

UPDATED May 30.

Save the date!  Pitt Peregrine Fledge Watch will be Thursday May 30 through Wednesday June 5.

We’ll gather at the Schenley Plaza tent, above, to watch for the young peregrine’s first flight from the Cathedral of Learning.

See him walk the ledges and flap his wings to prepare for his big adventure.  Watch Dorothy and E2 show him how to fly with some really cool flight demonstrations.  See Dorothy keep the area safe for fledglings.  Last year she attacked a bald eagle!

I’ll be there with peregrine fans from Pittsburgh Falconuts and volunteer peregrine monitors from the bridges.  We’ll all swap stories about peregrines.  I can hardly wait!

My challenge, as always, is to predict the best watching days.  With one male chick this year I expect the time span to be brief.  Male chicks normally fly early and improve their skills quickly.

So here’s the schedule but check the blog for updates because this event is very weather dependent.  Peregrines don’t like to fledge in the rain.  (UPDATED May 30.)

  • UPDATE:  Thur. May 30, 1:00pm to 2:00pm.  Baby started ledge walking on May 28.  On May 29 he perched in the keyhole while his parents put on an airshow.  Great peregrine watching! Come to the tent.
  • UPDATE:  Fri. May 31, 12:30pm to 2:00pm.  Slight chance of thunderstorms; hoping the weather cooperates during my extended lunch hour.
  • Sat. June 1, 4:00pm to 6:00pm, weather dependent.  Watch the weather.  Rain and thunderstorms predicted.  I won’t be there if it’s raining/storming.
  • Sun. June 2, Weather Dependent!  noon to 2:00pm, possibly extended hours (stay tuned).  Watch the weather — more rain and thunderstorms predicted.  Though our chick will be anxious to fly I won’t there if it’s raining/storming.
  • Mon. June 3, noon to 2:00pm + after work 5:30pm to 7:00pm.  I bet he’ll be flying by now but he won’t go far.  This may be the best day.
  • Tues. June 4, noon to 2:00pm + after work 5:30pm to 7:00pm.  If Monday wasn’t best, Tuesday will be.  Stay tuned for updates.
  • Wed. June 5, 12:30pm to 2:00pm.  Might be canceled if activity is on the wane.  If “Baby” has left the nest zone, this day will be a bust. Stay tuned.
  • June 6 and remainder of the week: Not scheduled.  Stay tuned.

 

Come on down to Pitt Peregrine Fledge Watch!  Meet me at the tent!

(photo of the Schenley Plaza tent by Kate St. John)

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