I maintain my master database of references in Zotero because it does the best job scraping websites, but I like to use BibDesk (OS X) to manage the bibliographies for specific papers and projects because it works better with Texshop. I often have the need to copy a few references from Zotero to BibDesk. For this, I don't want to export and import files, but instead use copy-paste or drag and drop, if possible.
Go to Zotero Preferences.
Click the Export tab.
Select BibTeX as the Default Output Format, and close Preferences.
Now, whenever you want to copy a few refs from Zotero to BibDesk, Select the desired references in Zotero and either:
- Drag-and-drop them on BibDesk.
Go to BibDesk.
elect the "New Publications from Clipboard" menu item.
Edit as desired.
I am developing the Zotero autoexporting addon. So you have the possibility to export when the database is changing or even after a period of time. You can choose the format, split by collections and can start a batch file after the files are processed. If you have any suggestions or problems feel free to contact me, to make it even better.
For BibDesk specifically, you should also have a look at Zot2Bib, which automates this: http://mackerron.com/zot2bib/
I use a plugin called zotero-better-bibtex (https://github.com/retorquere/zotero-better-bibtex)
Once installed you can select one or more collections (or the all bibliography) and export it as a file.bib.
It allows also an auto-file-export. Any time the collection is modified (new entry or other modification) the plugin auto re-export the file.bib where it was previously registered and replace the obsolete one. To do so, just select "keep update" when you first export your bibliography.
Open, then, the file.bib with Bibdesk and it is done.