Sure enough, at 8:13 AM, the tiercel zoomed in, and they did their now smooth-as-clockwork exchange.
The tiercel had barely landed when he was already at the back of the nest getting ready to settle in on the eggs, while his mate stepped to the front and decided which route she'd take to go get breakfast.
It took her all of 2 seconds to ponder the direction, and then she was off! She flew rapidly towards the Central Branch of the Free Library.
She then flew sharply downwards out of sight, and immediately there was an explosion of pigeons frantically flying up and away from the breakfast predator. We could not see whether she caught anything, but given the 50-60 pigeons that burst up from the ground, the odds are good that she successfully grabbed the slowest, most vulnerable bird.
We walked the three blocks or so over to where the pigeons had been, and saw that someone had spread many doughnut holes and bread crusts on the ground which had obviously attracted the large number of scavenging pigeons. Once again, we had witnessed the hawk's uncanny ability to locate potential prey from a great distance.
We returned to the nest, all the while watching for the return of the formel to resume incubation duties after her breakfast break. And we waited.... and we waited.... 9:00 AM.... 9:30 AM.... 10:00 AM.... 10:30 AM.... Where was she? Had she somehow slipped back onto the nest without our noticing? It's hard to miss a red-tail hawk!
I had my laptop with me, but could not pick up the Franklin Institute's wireless signal to access the camera feed to see if we could tell who was on the nest, so I walked around and into the Franklin Institute's lobby, leaving Kay on patrol at the nest.
When I pulled up the camera feed, I was startled to see that the hawk on the nest was the formel. How had she and the tiercel switched places? I asked the viewers - via the chat feed - whether anyone had seen the hawks change places in the last 15-20 minutes. I was assured that this was most definitely the formel, and no-one had seen a hawk fly in.
I felt like a child in the presence of excellent magicians - "How did you two hawks do that trick?"
Here are some of the comments from that conversation:
Sunnydixie: yet this bird has the wing marks like the female -- however the head looks stripier than the female. Her head color is more blended.
Sunnydixie: I'm REALLY confused now....
Mmggolfer: just like the pix I sent you the other day - no question in my mind that it's mom unless I was wrong to begin with.
Mmggolfer: Besides, too calm to be dad - he would have taken off a long time ago :)Winksmom: I'm pretty sure it's Mom sweet soft face white bib and sitting like she's happy to do so. I think it's Mom, Della.
Char8582: Hello all:)
Char8582: Has Mom been away long?
Char8582: Oh I see this is Mom...looks like Dad to me!
Char8582: Did they just switch??
CatzeePA: G'mornin..Mom just preened and stretched and changed positions
Char8582: I got up for a minute and thought they switched!
Mmggolfer: Still mom - just watching the world go by - stood up, checked out her eggs, and sat down again.
Meanwhile, back at the nest, the sitting hawk had stood up, leaned over to turn the eggs, and then had turned around to look out, and Kay had taken its picture.
It was the tiercel with his unmistakeable brown bib!
Kay zipped around to join me inside the Franklin Institute, and confirmed that no hawk had flown to the nest. We looked at the picture she had just taken, and then looked at the camera feed, and by the feather markings on the wings and tail, and what we could see of the hawk's face, and by everything we knew about ID'ing these birds on the camera feed, the bird on the nest seemed to be the formel, yet the picture Kay had just taken was of the tiercel. What was going on?
With nothing to be gained by continuing to watch my laptop screen, we went back out onto the street, and no sooner had we turned the corner and could see the nest, but a hawk flew in. So we were pretty certain we had both hawks on the nest. Almost immediately, as is their routine, the sitting hawk flew out and it was definitely the tiercel, leaving the newly arrived formel on the nest.
So, the bird that we had all been so sure was the formel sitting on the nest, was in fact the tiercel, and the formel had indeed been away from the nest for over three and a half hours. The tiercel had done a super good job of patiently staying on the eggs, only getting up once that we saw to stretch, turn around and move the eggs.
He flew over us almost directly overhead, and we could easily see his dark bib under the beak.....
..... the beautiful symmetry of his plumage.....
He headed across the Ben Franklin Parkway to his usual perch in the trees alongside the Barnes Museum construction site (formerly The Meadow), but before he landed, he showed off his phenomenal flying skills, zipping through and around the branches....
.... before settling in his chosen tree to recover from his marathon egg-tending session.
So even though it is really easy to tell the difference between the male and the female hawks when they are in flight, or when they are both on the nest, we learned today that when looking down at a single hawk on the nest from the camera feed, it is very easy to confuse one for the other.
John Blakeman offered the following observation about the feathers on the hawks' heads:
"Here's a quick screen grab of both birds. The tiercel, with his slightly streaked, mottled head feathers is on the left. The formel's head feathers are much more uniform, on the right."
Good luck, hawk watchers!