Okay, I just looked ahead in my calendar and the old birthday was STILL there. I removed and re-added my Google account and it disappeared. This time for sure I hope.
So, for those still paying attention, to removed a Birthday from Google's Contacts Birthdays & Events calendar:
1) Go to the Google Calendar website. Delete the birthday from the Contact.
2) While still on Google Calendar's website, unsubscribe and resubscribe to the Contacts Birthdays and Events calendar.
3) On your Pre, remove and re-add your Google account.
Isn't Cloud computing something?