FRE 301, enacted by Act of Congress in 1976, after the last BIA decision on this burden-shifting question, adopts the "bursting bubble" theory of presumptions, under which a presumption disappears once a party comes forward with "some evidence" - "more than a scintilla" of evidence - to rebut the presumption. Once a party comes forward with that evidence, the Government has the burden to prove the fact in issue. The Federal Rules of Evidence are not binding in immigration proceedings, but they are strong persuasive authority, esp. since this was specifically enacted by Congress.  This rule should be applied to the presumption of alienage from a person born abroad. See Chuck Roth, 6 Benders Immigration Bulletin 256 (3/1/01).