Sunday, March 16, 2014

Curiouser and curiouser

What are the Franklin Institute hawks up to?  And where are they going to build their nest?  We are no further along this week in understanding whether they will return to their old nest on the window ledge, or whether they really are going to take up a new nesting spot on the Amtrak lights tower.

The bad news is that while they spend time on and around the Franklin Institute, they have not been observed taking any interest in the nest there.  The good news is that their interest in the tower seems desultory and random -which is good, given its hostile setting for fledging eyasses.

            Carolyn Sutton

The tower is the T-shaped object to the right of the red-topped PECO building.

Adding to the confusion was the appearance this week of a third red-tail hawk.  The intruder showed up on March 13.

            Dinko Mitic


It looked very like Mom until one noticed the broken feather at the end of the left wing.  T2 has a similar broken feather (sustained back in December), but his chin and chest are clearly paler.

            Dinko Mitic


There was lots of circling by Mom and T2 and high-speed chasing of the intruder who flew into a tree near the Franklin Institute. Its chin is much paler than Mom's though it has similar chest streaks.


            Dinko Mitic


While the intruder was sitting in the tree, Dinko photographed Mom as she circled in the sky above. Her dark chin is clear, as well as her unbroken wing feathers.

            Dinko Mitic


It was a windy day, and the intruder experienced a sudden updraft!

                                        Dinko Mitic


The intruder flew off across the Ben Franklin Parkway towards the Rodin Museum, and T2 was seen following.  Another excitement last week was when Mom spied an empty nest in a tree.

                   Kevin Vaughan


She launched and grabbed at it with her talons...

                   Kevin Vaughan


                      Kevin Vaughan


... then flew across the front of the Art Museum with the nest trailing behind her.

           Kevin Vaughan


           Kevin Vaughan


Finally, this week a juvenile bald eagle came flying through our hawks' territory.  Dinko captured the eagle flying close to the Art Museum.

            Dinko Mitic

                                       Dinko Mitic


The Art Museum remains a favorite perching spot for the hawks, and Carolyn Sutton, Kevin Vaughan and Dinko Mitic have captured some gorgeous pictures of them consorting with the gryphons and sculptures that top the roof.

Here's Mom:

            Carolyn Sutton


              Kevin Vaughan


                                      Dinko Mitic


                                        Dinko Mitic


Here's T2 making a graceful landing.

                                       Dinko Mitic


With so many questions about what is going on with the hawks this spring, I decided to check in with John Blakeman to see what answers he might have, and he kindly provided the following perspectives:


Q)  Is it still possible the hawks will return the old nest at the Franklin Institute?

A)  There is still an outside chance that residence will be taken once again at the FI nest ledge --- but red-tails are famous for doing just this - electing for no good reason to build and use a new nest not far from the previous nest.  I hope the FI pair decide to return. But that is now in real question. The next week or two will tell.


Q)  Why might the hawks do this?  Is the recent brutally cold winter a factor?

A)  Weather or past experiences probably play little or no roles. Instead, I think it's just the nature of red-tail pair bonding. The building of a new nest by the pair is not unlike a young human couple moving into a desired new house or apartment. The whole endeavor strengthens the pair bond, sense of territoriality, and all the other social accoutrements of red-tail pairing. All of this results in stronger nesting and parenting behaviors.


Q)  Why would they pick that Amtrak lights tower?

A)  One factor that might be at play, one that I've been concerned about, is the low elevation of the FI nest. It's simply not very high, compared to adjacent or nearby nest support structures. Red-tails seem to prefer higher nest sites. They can see things better up there; eyasses can fledge more easily (lots of glide time before hitting the ground), and the nest is more easily watched by the non-sitting haggard. I think this is why Pale Male has had such fidelity with the present and historic Central Park nest. It's twice or three times as high as the Central Park trees.


Q)  What is the significance of this week's intruder hawk?

A)  The haggard interloper was a migrating floater (unmated hawk), attempting to mate (not copulate). Very natural and normal in March. The same thing was seen at the Cornell nest, where a haggard floater actually went to the nest with a sitting resident formel, perhaps on an egg. Nothing good or bad will happen from these threesomes. Short incidental things.


Q)  Is it possible that even though Mom and T2 have frequently copulated this spring, they will not get it together to build a good nest and lay eggs?

A)  Nest building is a profoundly enjoyable activity of mated pairs. They are not going to forego that cavalierly. I think virtually all copulating red-tail pairs will nest, and most often have eggs. If not, there is some underlying medical condition preventing ovulation and egg formation --- which by itself would have probably stopped copulation.


Q)  And a check-in about T2's broken wing feathers on his left wing - will this be a problem for him in any way?

            Dinko Mitic

A)  T2 is fine. The tips of these primaries are commonly broken off during the year. The bird is very slightly disadvantaged, but it makes up for it and works around it. The feather will be replaced in the summer molt.  It is of no concern, and is a rather common occurrence, and happens most often when chasing and taking squirrels in trees, where the feather tips get caught in branches.


            Dinko Mitic


As always, I must express my huge gratitude to the devoted photographers - Dinko Mitic, Kevin Vaughan and Carolyn Sutton - who not only spend hours out in the cold and often dark mornings to capture these magnificient images of the hawks and who allow me to use them to illustrate this blog, but who also take the time to upload their pictures to the Franklin Hawkaholics' Facebook page thus allowing so many hawk fans to keep up with the action.

8 comments:

  1. Thanks so much for keeping us informed and for contacting John Blakeman. It is satisfying to have some answers to questions we have all been asking. Thanks also for your great story and for your choice of exceptional photos from our wonderful "staff."

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  2. Hi Della !

    Love and follow your blog.

    Could the deaths of the 2 juvies from last year play a part in the lack of enthusiasm for nesting again on the FI ?

    :)

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    1. Hawks are not wired to feel emotion and mourning for lost offspring in the way mammals are. Because their eyasses were fledged juvies, and it was getting later into the summer, it would be as if the juvies that died had headed out for early migration. So it's unlikely that this is a factor in their choice of potential new nest site.

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    2. Thanks for answering my question, Della !

      Hope Mom and T2 wise-up soon and continue to use the FI nest to raise their young.

      :)

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  3. Thank you for this wonderful report and fantastic pictures. I look forward to more this season!

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  4. Thank you and to John Blakeman also for the update and information about not just Mom and T2 but hawks. I enjoy the photos and look forward to them each time I open my computer.

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  5. Would the FI consider putting another ledge nesting platform higher up on the building? What do you think?

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  6. Hi Folks. I wonder if the hawks could be lured back to the nest by placements of food near the nest. This would provide time near the nest and that may cause reuse. Bob

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