Anders Peltomaa asked that I post a correction about the events surrounding the discovery of the Red Crossbills. To quote Anders...
"Here are the 3 events as they occured:
1. Jacob had a two-three second look of large finches flying overhead early in the morning. Their calls lead him to think RECR and what he had time to see "fit the bill" for that ID. This was around 6:30-35am. I met him around 8am or so and that's when he told me of his sighting and hearing. He had looked for the Crossbills in the Pines of by Strawberry Field, but not seen them again.
2. Jacob's report and sighting encouraged me to start a search of conifer stands, Cypress Hill, South of Turtle Pond, Belvedere Castle, and when I stepped down to Shakespeare Garden I first heard the calls from the Crossbill flock. When I got visual contact they were in the air and flying south and disappearing out of sight across the 79-81st Street transverse. (Insert, "Darn, they are gone" which was my thought.) This was at 9:45am.
I called Jacob who had gone home after we met, because he needed to pack for his return to college. He re-posted to ebirdsnyc and I sent out a NYNYBIRD alert. After a few minutes the flock returned to Shakespeare Garden and I got my first photos to confirm the ID. Then I posted to ebirdsnyc and sent another text alert.
After this other birders started showing up, first was David Barett and Jeffrey Kimball.
3. I got an email from Andrew Farnsworth who asked to get audio recordings of the flock's calls so that the Crossbill Type could be decided. During a couple of their flights I got two recordings and sent the best one via email to Andrew Farnsworth. Later during the day I received an email from Matthew Young (AF had forwarded him the sound file for spectrogram analysis). The Red Crossbills that visited us matched Type 3. Jacob had mentioned he thought their calls were good for Type 3, but it was the flight-call-wizards of Cornell Lab of Ornithology, Andrew Farnsworth and Matthew Young who should be credited for the Type 3 ID. They alone made the exact ID. I gave them the sound file, but the id down to species type I would not trust my ears. When I first heard them I knew they were Crossbills, because their call is so distinct and it's a species I got a lot of exposure to last summer in Sweden when there was a huge irruption over there."
While I'm sorry for not crediting all the right people in my earlier postings or getting the timeline correct, my sincere thanks goes out to everyone involved. Central Park has some of the country's best birders who are extremely generous, both in sharing their observations and their expertise.
There is something about studying any new bird species that just gets you to think "Wow". With these Crossbills it is how incredibly well specialized their bills are for extracting seeds from cones. It was amazing to watch them.