Elly, is the term 'witches broom' a new one to you? I'm sure you've seen them, but didn't know what they were. They don't qualify for barred owl housing. (See image in the attached link.) Spinster, I heard barred owls many times last year. One would even land on the peaks of our roof and call away. THAT'S something that will make you jump right out of bed! Anyway, a witches' broom is a dense cluster of branches, seeming to rise from a central point. It is a mutation found on a wide number of woody plant species, and is caused by a genetic mutation, or by a mutative response different kinds of insects. They can be huge or very small. Some witches' brooms result in some interesting new plant cultivars. The ones found in conifers are often hunted and collected. Here is a link that might be useful:

Agree,...very cool!

It seems a little late to be nesting, but Barred Owls can be very protective of their nest.

woodswatcher: Although I claim to be no Barred Owl authority, I have observed them from near and far, for many years. I have called them up (with a Barred Owl call) while fully camoed in the early Spring, and had them land on limbs right in front of me. Twice in my life, I have called one up, while camoed and unseen by the owl--which confused him and got him calling and looking. A female came to his call, and the two mated on a limb right in front of me! I tried to nurse a Barred Owl with a broken limb (in my bathtub with the shower curtain drawn), but he kept pecking off the splint I so laboriously taped on his wing-bone, and it never healed. I used to go out in the country, and shoot into a flock of Starlings with a shotgun, and take the 5 or 6 home for owl feeders, that were wounded (generally broken wings) but still alive. I'd throw one in the tub, and draw the shower curtain, and later when the lights were out, I'd hear the Starling shriek as he was caught by the owl, and dispatched. (This, MANY years ago.) I've seen Barred Owls hunt in the daytime, when Winters were terrible, with snow 3' deep for months. Prey birds and animals died of starvation, or were underneath the snow, and Barred Owls were starving. In such disastrous periods, they hunt by day (and probably night, also). But I must say, I've never seen a healthy Barred Owl hopping around as you describe. Someone who studies Barred Owls exclusively would know WORLDS more about them then I. Just thought I'd check in because I know a bit about them, and have never seen such behavior. But I don't know enough about them to know if they go through a molt, which might incapacitate them as you mentioned. And, your thought about the owl being struck by a car is a very reasonable scenario, also. Where's a Barred Owl expert when you need one?