pechaflickr = the sound of random flickring

This is the "heather" mode of pechaflickr... a slideshow of 3 random flicker photos will appear on screen for 10 seconds each.

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

pechaflickr.netnotes and Q & Agitub code
pechaflickr is a cogdog production
cog.dog@cogdog