My buddy Patrick enjoyed catching an occasional ballgame, but he was very particular about the teams he supported.

Of all the professional sports teams out there,
Patrick was a fan of only three of them:

The Arizona Cardinals of the NFL,
the Atlanta Hawks of the NBA,
and the Baltimore Orioles of MLB.

Other than being named after birds, what common,
specific factor is shared by these three teams?

Here is the SOLUTION.

THE SOLUTION:

Each of those three teams moved to their current locations from St. Louis, Missouri. The Arizona Cardinals were the St. Louis Cardinals; the Atlanta Hawks were the St. Louis Hawks; and the Baltimore Orioles were the St. Louis Browns.
Did you come up with a different (but correct) answer? Feel free to share in the comments. Thanks!