Images on Flickr (and other sites?) can be tagged with “machine tags“. For living things, these can convey taxonomic information. For example:
taxonomy:binomial=Larus melanocephalus
taxonomy:genus=Larus
Flickr collapses these to:
“larusmelanocephalus” and “larus“, but note that subtracting one from the other gives the specific epithet, “melanocephalus“.
For subspecies, use:
taxonomy:binomial=Larus glaucoides
taxonomy:genus=Larus
taxonomy:subspecies=Larus glaucoides kumlieni
and for other ranks:
taxonomy:class=Aves
Here’s an example: http://flickr.com/photos/pigsonthewing/2238938901/
Well, what are you waiting for? Tag away!