
Vietnamese-American Hunter Nguyen, 56, was stopped at Tan Son Nhat Airport in Ho Chi Minh City on Tuesday when an X-ray machine detected moving objects in his carry-on luggage.
A further search revealed the birds in to a small cage inside the suitcase.
"There were 21 birds in his suitcase, including 15 magpie-robins and six nightingales, without a permit," said Nguyen Thanh Tuyen, chief anti-smuggling officer at the airport.
Officials confiscated the birds, but let Nguyen board the plane, bound for the US, transiting in Taiwan. He may later be fined, Tuyen said.
It was unclear what Nguyen intended to do with the birds once he arrived in the US.
//Deutsche Presse-Agentur (DPA)