Originally made by @xxcd, I adapted this shortcut to display birthdays occurring "today" and "tomorrow" as well as the next 7 birthdays on your calendar (as driven by your contacts).  I reformatted the date to show it clearer for US (Tue, Nov 6).

If the event occurs today, a small balloon will appear next to the item to give you instant acknowledgement that the birthday is occurring.

Sample event listing:

🎈Today (Mon, Nov 5)
John Doe’s 35th birthday

Tomorrow (Tue, Nov 6)
Allison Doe’s 74th birthday

7 days (Mon, Nov 12)

Jane Doe's 56th birthday