Sunday, October 14, 2012

The Big 1-2!

This year for my daughter's official 12th birthday she wanted to go birding. Oh what a surprise! This time around I could not take a dozen girls (like last year) for a day trip and crossing three bridges to boot! She knew that none of her friends are birders like her and none would like to spend the whole entire day looking for birds. So she asked her friend, the one and only Rachel, who's known her since both were in utero, to come share her 12th birthday with her. And she graciously did!

We headed out early on a Saturday morning to Marin. Every Saturday during the months of September -October they have free Hawk Talks and Banding Demos on the Hill. You see.. it's Raptor migration time! And Emily wanted to see raptors. Enough shorebirds.. it's time to see the Birds of Prey.

So we headed up to Hawk Hill in the Marin Headlands.
It was a very happenin' place! Apparently a group of volunteers from the GGRO (Golden Gate Raptor Observatory) come daily during Sept-Oct to count the migration of raptors. They were set up with binoculars each taking a specific area and yelled out what they saw to a person in the center who was tallying the types of birds that were seen. These are dedicated birders I tell you!

At 12noon, an intern from the GGRO  gave a very comprehensive Hawk Talk.
Here I am vigorously writing everything that she says so I can remember to blog about it. My memory isn't like it used to be.
She first asked us what a raptor was.. birds of prey.. duh! But what distinguishes them from other birds are three main characteristics:

1) large eyes (for seeing it's prey)
2) large sharp beak (for tearing it's prey)
3) sharp talons (for catching and killing it's prey)

Size isn't an essential characteristic since, as you can see from the picture above, those talons are very small. It's from an American Kestrel, one of the most ferocious birds of prey if you can believe.

One of the most common ways to determine what type of bird it is is to learn their distinguishing characteristics of their underside when they are in flight. You can immediately tell (so experts say) what kind of raptor is it by looking at it's wing shape, feathers and tail. And watch how they fly is also key!

Raptors fall into three families: Budeo, Accipter and Falco.

Buteos are the lazy hawks. They are robust hawks with long broad rounded wings and short broad tails. They mainly soar and glide for quite awhile in wide lazy circles. They hunt mainly from perches dropping to the ground to capture it's prey.

Buteo lineatus : Red Shouldered Hawk wing




Accipiters alternate flapping and gliding. They live mainly in deep wooded areas. They have short rounded wings and long rudder-like tails which allow them to maneuver among the trees. They have a recognizable flight pattern which consists of several rapid flaps and then a glide. As a group, accipiters are secretive and are observed less frequently than most other hawks.
Accipiter striatus: Sharp Shinned Hawk wing
Lastly there are the Falcos which are the fastest flying hawks. They have narrow, pointed wings and long narrow tails. They are birds of open air and are rarely found in wooded areas. They primarily feed on other birds and usually capture their prey in mid-air.

Falco sparverius: American Kestrel wing
Other than the birds wings, their tails are very distinctive also.
Two drastically different hawk's tails: red-tailed hawk vs an american kestrel
In flight, we saw...

Can you guess? Is it a buteo? accipiter? or falco? (answer at the end of the post)
 and...
Cathartes aura: the Turkey Vulture
...we even saw a few of these. Turkey vultures are not raptors since they eat dead animals. They are called scavengers which ride thermals (hot area tunnels) in the sky and use their keen sense of smell to find fresh carcasses.

Now owls are a whole new category of raptors. They are nocturnal and solitary birds and the only raptor that has feathers all the way down it's leg and feet to it's talons.

Leg from a Great Horned Owl
At Hawk Hill, they have a diagram showing the lengths of all the wing spans of the birds that are in our area from the largest (California Condor) to the smallest (Anna's Hummingbird).
Rachel's arm span is as long as an Osprey hawk
 Here is a picture of an osprey:
An osprey in flight from graham owen images
Below is a cool guide to help you decipher what kind of hawk is flying in your area..


Next Up: Banding... So Cool! You don't want to miss this post!

ANSWER: The hawk in flight is a Buteo... a red-tailed hawk! Did you guess right?

1 comment:

valerie c. said...

yes! i guessed correctly--but that's probably because i see alot of them here at the coast!