Twig Harvesting

I'm wondering if I'm the only bird watcher out there who didn't know how birds harvest twigs. I really hadn't given it much thought until I first saw the red-shouldered hawk female fly to a nearby pine and return to the nest with a fresh pine twig clutched in her talons. The female is the hawk in the upper right in the image below.
These hawk images were taken April 4th before the leaves came out. The female is just landing, relieving the male at the nest. Below is a closer view of her talons gripping the pine twig and the male as he lifts off the nest. When it comes to smaller birds, I assumed nesting materials were gathered loose, that birds simply found them and picked them up. I've certainly seen many birds flying with their mouths full of grass, straw, string. But I never really thought about where or how they got their twigs.
While sitting in 'Red-shouldered hawk territory' today, I watched this female cardinal moving about on a perch, fluttering her wings, swinging around, using her whole body in a manner that was puzzling at first, until I finally spotted the twig.
Above, she's pausing for a moment...maybe to rest? The light green spot on the twig above her head marks where she has been trying to gnaw it loose. Below she gives it another try.
And succeeds!
What a prize!
The more I watch birds, the more I learn and the more their ways and instinctive wisdom amazes me.

Next post: Another look at Red-shouldered Hawk Territory. The nestling is growing. Got a glimpse of him/her flapping little wings through my binoculars! (I've only seen one nestling so far.)