Show contacts’ birthdays in Calendar on Mac
When you add birthdays to contact cards, you can see the birthdays on the Birthdays calendar in the Calendar app — just make sure Calendar preferences are set to show the Birthdays calendar.
Ask Siri. When you add a birthday to someone’s contact card, you can say something like: “When is Lucy’s birthday?” Learn more about Siri.
The Birthdays calendar is updated automatically when you add or remove birthdays in Contacts.