pechaflickr = the sound of random flickring

This is the "heather" mode of pechaflickr... a slideshow of 20 random flicker photos will appear on screen for 20 seconds each.

Can you guess the tag that is common to all the photos?

pechaflickr.net • notes and Q & A
source code licensed GPL3.0 and also placed into the public domain using CC0
now available in german
pechaflickr is a cogdog production: cog.dog • @cogdog