pechaflickr = the sound of random flickring

This is the "heather" mode of pechaflickr... a slideshow of 10 random flicker photos will appear on screen for 10 seconds each.

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

pechaflickr.net • notes and Q & A • gitub code
now available in german
pechaflickr is a cogdog production: cog.dog • @cogdog