How do I remove duplicate birthdays on the calendar?

[RosevilleFan]

My phone is 7.0. One duplicate has a G+ account, the other does not.

 

[SpookDroid]

Most likely one is saved locally and the other synced from Google or Google+. Just go to your Calendar app (the exact method will depend on the app you're using, but the general steps should be the same), find the menu button, and look for a 'Calendars to Show' or 'Calendars' section. There you should be able to turn off 'Birthdays' or find the duplicate calendar.