Somehow, when People was automatically populated from my Hotmail/Outlook account by Windows 10, a bunch of the contacts wound up with birthdays of 01/01/2000 set. That resulted in a series of "Happy Birthday" e-mails on the first. I have looked at clearing those, but there is no option to clear them, only to change them by selecting different date factors. E.g. I could change them to 07/04/2000 and get dozens of birthday messages on Independence Day instead of New Year's Day. I'd rather not.

The other option might be to delete the contact and re-submit it. I'd rather not.

Any ideas at how I can get to these and clear them?