Show or hide the Birthdays calendar on Mac
The Birthdays calendar displays birthdays it finds in the Contacts app.
In the Calendar app on your Mac, choose Calendar > Preferences, then click General.
Select or deselect “Show Birthdays calendar.”
You can’t add or remove birthdays directly in the Birthdays calendar; instead, you update them in the Contacts app. When you add or remove birthdays in Contacts, the Birthdays calendar is updated automatically.
If you add calendars from your Google account, a separate Birthdays calendar shows the birthdays for those friends and contacts.