Saturday, January 21, 2012


This, ladies & gentlemen, is a Gyrfalcon: Falco rusticolis.  It showed up at a wildlife refuge in Riverside County, California.  Here's the crazy thing: just in case it is an escaped falconer's bird, they don't want us specifying where exactly the bird is hanging out.

I don't think the bird is an escapee from a falconer for multiple reasons:

1) It is a juvenile.  Juvenile Gyrfalcons are known for vagrancy. They show up much further south than the adults.  That said, this is ridiculously fr south for a Gyr.
2) It is a brown bird.  Gyrfalcons used for falconry are the white morph birds of the high arctic. For an intellectual exercise, I went on the internet to buy a Gyrflcon.  There are not a lot for sale, and they are very expensive. The odds of some dumb guy losing his $50,000 imature brown bird are absurd in totum.

3) The bird that showed up in Orange County was an adult white Gyrfalcon with a jess on its leg.  Enough said.  Click here to see photographs and read about that obvious escapee.

4) It's not wearing a jess, or other falconry equipment.

4) The length of the tail vs the wingtips.  A very knowledgeable bird expert (who I know, like, and respect) pointed out that the bird's primaries i.e. wingtips should be proportionately much shorter, when compared to the length of the tail.  This raises the suspicion that this falcon is a captive-bred hybrid of Gyrfalcon with some other species.  I think it just happens to have long wings i.e. there is probably a lot more naturally occuring variation than we are aware of.  Otherwise, the plumage looks good.

The constant clicking of camera shutters was deafening.
  Rough-legged Hawk
Buteo lagopus

Rough-legged Hawk

Rough-legged Hawk perching on a thin branch.
Rough-legs are known for doing this, and are portrayed in this pose in many books.  Unlike other large hawks, they are light enough to do this.
Rough-legged Hawk
     Look closely at this hawk's legs: they are feathered all the way down to the toes, unlike other members of the genus Buteo.  This is because they live in the high north, where it is cold.  Eagles are essentially large hawks with feathered legs.  Gyrfalcons have this same oddity that separates them from other members of Falco. 
     DNA analysis has shown that falcons and hawks are not at all closely related.  Rather, they have arrived at the same hunting lifestyle through convergent evolution.  Unsurprisingly, falcons are related to parrots.

Western Meadowlark
Sturnella neglecta
Gyrfalcon (Falco rusticolis) and American Kestrel (Falco sparverius)
The Kestrel constantly harassed the Gyr.
That's like a Dachshund attacking a Pit Bull.
Note the size difference between North America's largest and smallest species of falcon, both in the genus Falco.  The species of kestrel found in the U.S., Mexico, and Canada is a different species from the bird simply called Kestrel in Eurasia.  Click here to see a beautiful close-up photo of an American Kestrel.  Click here to see a Eurasian Kestrel.
American Kestrels eat large insects like grasshoppers and dragonflies, and small birds like House Sparrows.  Gyrfalcons eat ducks and rabbits.
Lee Swanberg (left), retired teacher.
Lee and I have carried out winter bird censuses up in Mount Baldy's Ice House Canyon, together.

The smallest falcon I've ever seen is the Bat Falcon in the tropics. Yes, they eat bats.


A. Samuel said...

No doubt that is an immature grey phase gyr. One correction, that would be about a 3000 dollar bird, not 50,000...even white ones are trading close to 12,000.

Good photos.


Thomas Geza Miko said...

Thanks for the price correction. It was based on an article about Russian customs agents catching a woman with a bunch of white ones "worth $50,000 each".
Tom said...

Hello, I would like to ask you for permission to use one of your photos. Is there an e-mail under which I could reach you?
Thank you!