This question already has an answer here:
In the BibDesk wiki (BibDesk Tips and Tricks) there is some information on customizing BibDesk for biblatex, including a link to a TypeInfo file that can be used to create all of the biblatex fields automatically. The has to be saved as ~/Library/Application Support/BibDesk/TypeInfo.plist.
Im using texmaker, bibDesk under osx 10.9.5. The folder doesn't exist so I created it. Didn't help.
Does anybody know where to copy the "TypeInfo.plist" file?
Alan Munn refers to this in that Question: Bibliography tools that are compatible with biblatex and biber