I am starting to use org-contacts and wanted to unify my existing 
"Birthdays" list, with the new formatted contacts I am creating.

Do the anniversaries have to be out of PROPERTIES?

Example: This is not "parsed into agenda":

:PROPERTIES:
:BDAY: %%(org-anniversary 1980 02 19)
:END:

BTW: Thanks for your advices with org-capture. I found too a very useful 
introductory video from Protesilaos (I wasn't able to understand the 
documentation till I watched this video): https://youtu.be/qCdScs4YO8k