why can't I delete birthdays from my calendar?

You can't just unselect the Calendar to stop the birthday notifications. That's why this question has been asked. Unchecking the birthdays calendar continues to deliver birthday notifications. Please don't respond if you don't know the answer.

Hello.

I think the reason behind this is it links them from contacts and attaches them to Calendar. You will have to go to Contacts and delete them there from each person's contact card. You can also just unselect the Calendar under the Calendars tab to not see everyones birthdays.

Hope this helps.