I haven’t seen these around, but I do like the images they have up at this gallery. Here’s the lowdown from ODK:
green bird is a non-profit organization which has been running these cute ads around tokyo promoting cleanliness and courtesy to the environment with the slogan “keep clean, keep green.” Their print ads are available online in the gallery, but their excellent animated commercials are, unfortunately, missing from the site. If anyone knows where to find them, please drop a note.
They’re definitely taking a cue from the JT Tobacco smoking-etiquette campaign.