I did all the basic steps to sync the facebook with ios i.e.,add a account in settings and check the calendar to sync with iOS. After adding my account, It's not getting synced.
How can I sync facebook birthdays with my iOS Calendar?
I finally figured it out!! After following the steps that Bobby listed above, do the following:
Settings > Facebook > Enable "Contacts". Open up the Calendar App > Select "Calendars" on the bottom > Select "Birthdays" under Facebook.
It took about 2 minutes for "Birthdays" to show up on my iPhone after enabling Contacts.