Friday, April 29, 2011

Nest Cam Addict Returns!

Yes, it's the return of the nest cam addict!

Thursday was banding day for the San Jose and San Francisco peregrine chicks (4 in each nest). It's always fun to watch the banding at San Jose, as the nest cam, located atop City Hall, has streaming video, so you can see every moment.

First the parents start swooping by the nest box, then the camera focuses on rappelling ropes dropping down, and it's showtime!

The banding video is available online here. It's in five five-minute blocks (abbreviated from the full banding sequence). edited: The long version now comes up first, but there are shorter versions off to the left that you can change to. Banders both in San Jose and the Midwest wear helmets because the defending parents are very protective of their young. Glenn Stewart in San Jose occasionally has a helmet cam.

Neither the streaming video or the banding video has sound, but you can see the chicks' beaks moving as they are picked up and observers from the nearby parking garage reported that the parents were kakking alarm cries.

It's interesting to watch the chicks huddle together as each sibling is picked up. The last remaining unbanded chick tried crossing the nest area to hide among its banded siblings while Glenn was working on #3.

Banding time is also when the watchers find out what the sex of the chicks are. And that is from the size of their feet.

From the site
"Q&A: Q. How do you know what sex the chick is when you band it?

"A. By the time the chick is old enough to wear a band, we are able to sex the bird by the size of its feet and thickness of the tarsus. By the time they reach 3 weeks of age they have achieved adult weight at about 650 grams for males and 950 grams for females. As you can imagine the difference is quite obvious to the practiced eye. If there is any doubt we use the larger female band."

Looking at how big some of those chicks are standing next to their father at past feedings, I've got my guesses. I'll find out for sure soon. (later report: 3 males and 1 female. My guesses were off.)

Prey remains are studied, so you'll see, once banding is done, that Glenn will sort through and bag feathers and other material from the nest box. Then it's a wave to the watchers atop the parking garage, and he's back up the wall.

The chicks recover fast - usually falling asleep in a heap - but the parents will continue to make attack runs until the humans leave the City Hall roof (a victory in peregrine terms).

And now it's back to watching. The chicks have discovered their new bling and the watchers can identify via band number and start to attach a personality to each chick (they will receive names later). The wandering stage began Thursday night when the chicks started exploring outside the nest box. More fun!


  1. Wow, Kathy, this is so interesting! Thanks so much for sharing.


  2. I bet the birds wonder what in the world are these crazy people doing. We have a local group that work through Texas Wildlife and band birds and butterflies and do a lot of stuff with children. It is fascinating. I always wondered how they could tell whether the Monarch is male or female, then they explained it.

    Right now I'm watching hummingbirds fight over the feeders. They're so territorial. A few days ago we had 4 baby plovers at our pond. I think I'll check on them and see if they've flown away.