Modifying this control will update this page automatically

Show or hide the Birthdays calendar on Mac
The Birthdays calendar displays birthdays it finds in the Contacts app.
Go to the Calendar app
on your Mac.
Choose Calendar > Settings, 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.