Md. Code, Natural Resources § 10–309.1

A nonresident may provide waterfowl hunting guide services for hunting snow geese in the State without a Maryland waterfowl hunting guide license if:

(1) The nonresident possesses a valid waterfowl hunting guide license from the nonresident’s home state;

(2) The nonresident’s home state allows a Maryland resident to provide waterfowl hunting guide services for hunting snow geese without a waterfowl hunting license from the nonresident’s home state if the Maryland resident possesses a valid Maryland waterfowl hunting guide license; and

(3) The nonresident purchases a Maryland migratory game bird stamp.