Tuesday, April 30, 2013

Disturbances in the field

Apologies for taking so long to post.  For some unknown reason, I've had some nasty technical difficulties uploading images.  A change of browser and an upgrade to my laptop seems to have solved the problem.

All is well on the nest.  Mom and T2 are doing a fine job with incubating their eggs.  It's getting close to the end of incubation, and hatching may start sometime this week.  

Here's what's been happening over the past couple of weeks.

Things got a little crazy down on Winter Street earlier this month.  A dumpster suddenly appeared in the parking area where hawkwatchers often gather, then machinery, another dumpster, a sand pile - a pop-up construction site.

            Marjorie Goodman


It turned out to be the start of a project to replace gas mains in the area. The parking meters were also removed, replaced by a parking kiosk. The contractor told Carolyn Sutton that none of the trees below the nest will be harmed. These trees are essential for successful fledging as they are usually the first landing spot out of the nest for the eyasses.  The nest is in the topmost window on the extreme left of this image.

          Carolyn Sutton

Everything apparently will be put back in good order when they leave at the end of July.  As the week went on, however, the construction site suddenly started to vanish as fast as it had appeared.



           Katy Mae

We surmise that this sudden change in plans was because of the huge Philadelphia Science Festival that engulfed the streets around the Franklin Institute, including Winter Street.



          Alec Rogers

The hawks sat serenely above it all, watching their streets fill with tents and pedestrians, and their skies invaded by a blimp.


Hawk cam watchers have enjoyed watching the changeover between the hawks when they switch places on the eggs.  This is when we get the best view of those eggs.


          Tess Cook


T2 can now add incubation to his string of new accomplishments.  He has become a real pro!  After he has been sitting for a while...


          Della Micah


... he will stand up...


          Della Micah


... lean over and start turning and rotating the eggs...

          Della Micah


... so that the warmth from his body is transmitted evenly over the developing embryos inside the eggs.

          Della Micah


Then he settles back down again, patiently awaiting the return of the formel.

          Della Micah


Mom, meanwhile, enjoys some me-time away from the nest in her favorite tree.


                             Carolyn Sutton


Her brood patch is visible here below her lowered head.

                             Carolyn Sutton


It must feel good to get off those eggs for a bit...


                             Carolyn Sutton


... and have a good stretch and preen.

                             Carolyn Sutton

Whenever she is away from the nest, she always has it in her sight line. A favorite spot is the lamp pole beside the Vine Street expressway.



                          Carolyn Sutton


Sometimes, she turns her back for a while...


           Kevin Vaughan

... but as relaxed as she can seem one moment...



           Kevin Vaughan


... if she spots possible prey down below in the grass, she goes on high alert in an instant.


           Kevin Vaughan


If T2 is in the vicinity, he will be watching the nest.


                           Kevin Vaughan

         
...even when it's wet and windy...


                           Kevin Vaughan

... mohawk weather!

                           Kevin Vaughan


OK - the good news is that T2 started to catch prey that is larger than a vole.  The bad news: that prey was a yellow gosling (baby goose).  Let's hope the goose cam was down that morning....

Both hawks looked slightly startled at what T2 had just brought in to the nest.

            Kevin Vaughan


Mom clearly realized this was a breakfast bonanza, and that sharing was not an option.

            Kevin Vaughan

She took off from the nest, and flew right over us with the gosling's webbed feet dangling, and headed for the Barnes Museum roof.

             Kevin Vaughan

This was the moment when we had to keep muttering, "Circle of life, circle of life...." as she ripped into the fluffy, yellow carcass....

            Kevin Vaughan

... scattering downy feathers on the breeze.

          Katy Mae

It serves as a reminder of how miraculous it was last spring that she allowed T2 anywhere near the nest with the week-old eyasses there, given his (and any hawk's) predilection for helpless fluffy creatures as a food source.

On a gentler note, we think we have figured out why the hawks keep bringing those round seed pods to the nest.  Here's Mom arriving with a pod.  This is one of Kevin Vaughan's most beautiful images with the sun-caught shadow hawks bookending her.


            Kevin Vaughan


The seed pods come from London plane trees, also known as sycamores.


          Katy Mae


Though they are hard and prickly on the outside, looking like tiny hedgehogs suspended from the branches, when you break open the pod, the seeds create mounds of fluff...


           Katy Mae

... which puff up into even softer piles when teased apart.  Could there be a more inviting nest lining for the eggs' precious cargo?



So in the next few days, the eggs should start pipping - the first sign of an imminent hatch for this marvelous pair of hawks who are about to embark on raising T2's first eyasses.


           Katy Mae

With my computer woes now fixed, I plan to keep you right up to date with all the eggcitement!

Friday, April 12, 2013

Incubation is going well

The Franklin Institute hawks are well into their second full week of incubation.  Watching hawks (or any birds) incubate eggs has been likened to watching paint dry.  Not much outwardly happens.  This is pretty much the unchanging view on the nest cam.

          Della Micah

From the ground looking up, she is tucked down in the nest bowl with only her head showing.  

           Kevin Vaughan

The big excitement is when T2 flies in to give Mom a break from sitting on the eggs.  This is when we often get a glimpse of those precious eggs around which they tiptalon so carefully.

         Katy Mae 

Once he arrives, she is outta there!  She has complete faith that he will cope with whatever antics the eggs might get up to.  T2 looks a little less certain!

           Tess Cook

He often arrives with his trademark gift of greenery...

           Kevin Vaughan

... and he now has clearly figured out how to break off large pieces with no problem.

          Kevin Vaughan 

He is also becoming increasingly comfortable with sitting on the eggs, and Mom sometimes has difficulty getting him up and off them when she returns from a break.

           Kevin Vaughan
 
          Kevin Vaughan

Sometimes, his gifts are edible and those get snatched immediately from him.

          Kevin Vaughan

 Definitely grab-and go food!

           Kevin Vaughan
          Kevin Vaughan

She often heads to the flat top of the nearby Civil War monument to eat.

           Kevin Vaughan

          Kevin Vaughan

          Kevin Vaughan

The hawks also use the monument as a food cache, and one morning, Mom cleaned up this large, unidentified food item.

          Kevin Vaughan

          Kevin Vaughan

Sometimes, after T2 has caught prey, he will first take it to the monument and eat some of it...

          Kevin Vaughan

 ... before heading over to the nest to take the rest back to Mom.

          Kevin Vaughan

          Kevin Vaughan

Other times, T2 will simply perch there surveying the city scene.

                          Carolyn Sutton

On Wednesday morning, T2 was very late for his changeover at the nest.  Mom finally had to stand up and stretch her legs...

           Della Micah

... then her wings

           Della Micah

           Della Micah


T2 -- call home!

           Della Micah

This is how she looked from the front while waiting for T2, tapping her talons, perhaps?

           Kevin Vaughan

Eventually, she had no choice but to settle back onto the eggs and wait for him to show up.

           Della Micah

Understandably, hawk watchers become nervous when T2 is not where he should be, as we well remember the anxiety and sadness of last year when we watched and waited for Dad, and he never came back.

The following morning, though, all was well in hawkdom as T2 atoned for the previous day's tardiness by bouncing in just after sunrise.

           Katy Mae

During this incubation period, hawkwatchers often notice that as Mom settles back onto the eggs, she wriggles and arranges herself quite carefully.  What she is doing is positioning her brood patch on top of the eggs to provide maximum warmth.  The brood patch is a bare area of skin under the belly feathers.

Here's an image of a red-tail's (not Mom) brood patch, visible only when the wind blows her feathers apart.


Most female birds develop a brood patch during the breeding season. Changes in hormone levels during the nesting season start the process. The tissue in the belly area swells, becomes moister, and the blood vessels that feed the skin expand. These changes make the skin of the brood patch almost as hot as the body's interior. When she sits down on the eggs, she wriggles her body back and forth until the skin makes best contact with the eggs.   That wriggling also turns the eggs so that all parts of the developing embryo get exposed to the warmth.

John Blakeman offers these additional comments:  "Formels, without question, have large, naked brood patches, against which they tuck and rock the eggs into direct contact. But I don't think (but don't yet know with exhaustive knowledge) that tiercels have a full brood patch. It appears to me that they lose only a reduced quantity of the downy breast feathers; that the eggs do get tucked up onto the breast, but not as well as with the formel's naked brood patch. I never saw a brood patch in the sitting tiercel in my Red-Tail breeding project. The brood patch of the sitting formel was very obvious."

Mom's brood patch is under those ruffled feathers, and you can almost see the pinker skin lower down.

            Kevin Vaughan

Earlier this week, instead of flying into the nest, she landed on the ledge alongside the nest, bringing back memories from last year when she picked up the rat food drops

           Kevin Vaughan

New hawk watchers will see this ledge used extensively later in May and June when the eyasses are old enough to explore outside the nest.

           Kevin Vaughan

What an imposing, beautiful hawk Mom is.

            Kevin Vaughan

                Kevin Vaughan
 
Whatever the excitement or travails of the day, by night fall she is always on the nest protecting the eggs from the chilly nights we're still having here in Philadelphia.

        Katy Mae

Every day, Kevin Vaughan shares his incredible images of these hawks on the Hawkaholic Facebook page Here are some recent spectacular ones!

Here's T2:

           Kevin Vaughan

           Kevin Vaughan

 T2 rarely looks intimidating...

                         Kevin Vaughan

                               Kevin Vaughan

            Kevin Vaughan

 ... but in this image, he looks unusually fierce.
 
           Kevin Vaughan
 

And now for Mom:

            Kevin Vaughan

She almost always looks fierce, but here's a more pensive view.

                                             Kevin Vaughan

          Kevin Vaughan

          Kevin Vaughan

          Kevin Vaughan

            Kevin Vaughan