A consolidated ball of a pigeon's down feathers, which gently rolls throughout the streets and sidewalks.
An urban equivalent (specifically the San Francisco neighborhood bordering Nob Hill & the Tenderloin, highly populated by pigeons) to the North American tumbleweed (Salsola pestifera) found in rural desert environments.
1. Tendernob tumbleweeds were swirling around my feet, carried by strong ocean driven breeze as the sun set on yet another bustling day in a towering city.
2. "Heads up bro, tendernob tumblweeds blowing your way, 12 o'clock."