Falcon Watch - Guarding the nesting territory

This nesting season falcon fans have been worried about challenges to Boomer and SW for their nest.  Here is SW’s new mate, Boomer.

SW’s mate from last year, Ranger, was in rehabilitation for many months after suffering serious head injuries and was finally released after his recovery in January.  There is always the worry that Ranger will try to retake his nesting territory from last year, but he has not been seen.  Perhaps Boomer chased him off at some point, or perhaps he decided not to challenge Boomer - we are hoping no news is good news, because falcons are known to fight to the death for their territory.  Fans have also been worried about SW’s advancing age.  This is SW looking through the skyscraper window at the human inside.

SW has been the female falcon at this nestsite since 2002 when she battled the previous female to the death for control of the nest.  Zenith, the aging queen of this nestsite for 9 years before SW, had the peregrine characteristic of migrating, leaving her nestsite unguarded during the winter.  The word peregrine means “wanderer” and peregrines have been known to migrate 1,000s of miles from their nest.  During Zenith’s absence in 2002, SW arrived at the nest and bonded with Zenith’s mate.  The story was much like this year’s story with the males, as SW bonded with a new male while her mate from the year before was absent – but there was a difference back in 2002.  By the time Zenith returned from her winter travels, SW had already laid 4 eggs and her instinct was to protect them.  This is a picture of SW on her eggs taken by the FalconCam just as Zenith returned.  We call this picture “Protect and Survive”:

Moments later, there was a fierce battle which ended the life of Zenith.  Now it is SW who is getting up in years and earlier this winter another female did enter her territory.    At first, SW was sitting on a ledge watching some pigeons below her.

Here are the pigeons she was watching.  Do you know why SW was so interested in pigeon watching?

Nest monitors, Mr. and Mrs. Saladin, watched the event unfold and told the story:  

“Thought we were going to see her dive off after the pigeons, but then she started vocalizing with the high-pitched rapid chipping that they use when another falcon is in their territory (as opposed to their kekking call when a different raptor is around).  As we were both looking up to try to find another falcon she took off (as you can see in this shot she's looking upward as she's flying)....

We saw two falcons (one presumably Boomer) flying together high up over the top of the Terminal Tower. We could tell that one was definitely a female from the size difference and flight. In these shots, Boomer is on the left and behind her...

And then Boomer flew in underneath her and ended up on her right here as they squared off...

In the meantime, SW was circling up, but then flew back in as they headed out and perched up high on the Key Bank Building. Waited for awhile, but SW remained perched and we didn't see Boomer return.

Remember that Boomer and the intruder were way up there, whereas SW started from a low perch, so they were actually heading out by the time SW was circling up in defense.  If that intruder would have flown down onto the nesting ledge (or anywhere close), no doubt SW would have been right there”.   Here is Boomer successfully chasing the intruder out of his territory.

“As it gets closer to nesting, we're sure that both of them will pick up the aggressiveness, but this may have been just a fly-over and perhaps not much of a threat. ….. it's generally females chasing off other females, although that's not always the case. Males do fend off intruding females.  Of course, resident pairs will have to deal more and more with intruders as their population increases and the intruders search for mates and sites”.

 

Will SW and Boomer keep control of their nest?  Will there be eggs?  Keep your eyes and browser set to:  http://www.falconcam-cmnh.org/news.php 

 

For more about falcons, go to http://raptorsinthecity.org/ 

Our thanks to the Cleveland Museum of Natural History for sponsoring the FalconCams.

 

The portrait of Boomer is courtesy of Scott Wright, volunteer peregrine nest monitor.  The series of photos of the female intruder are courtesy of volunteer monitors Mr. and Mrs. Saladin.   They may be used by children for school and/or personal projects, but please give photo credit. 

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