Yes, they're the regular burrs that dogs get in their coats and people get everywhere. Unfortunately, small birds like Kinglets perch on the tops of goldenrod and small bushes and sooner or later, burr plants. Their wings get tangled and the more they flap, the more they get snared. They shred their mouths to ribbons trying to pull the burrs off and they die slowly. It's quite horrible to see. (I had one die in my hands as I tried to rescue it out here in Miss'a last year.)