Hanging from the branches

 

We spent most of the day in an indoor meeting (near Wawona), but during a short walk in the late afternoon we spotted this wonderful nest hanging from the branches of a Western Dogwood (Cornus sericia).

We wondered about the white material scattered on the outside of the nest.  Can you tell what it is?

Here's a closer view:

 

Our best guess is flower petals, perhaps from the dogwood itself.  What do you think?  

I had also wondered if the petals had simply stuck to the nest, or if the bird purposely included them in the nest.  Most of the group felt the bird probably incorporated them into the nest, perhaps for camouflage.

And of course, we're all wondering which species of bird built the nest.  I don't know the answer, but if you do, let me know!