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!