Currently, you can search for authors with a given birth year, but no other variation of "Birthdate" search seems to work. If you search for "1918-01-26", you get the list of everyone born in 1918. If you want to see who else was born on Jan. 26, you would try to search for "01-26". You'll get nothing. (This was discovered when an author in the db asked me who else was born on her birthday, and I couldn't tell her.)
Anonymous
I should note that I was attempting to do this via "Advanced Search"
Implemented in:
edit/ap_search.py 1.18
edit/aa_search.py 1.18
Installed in r2012-49. Death dates were also changed.