Alleged bird smuggler caught by Miami airport security: Investigators

A man who allegedly tried to smuggle 10 birds out of Cuba was caught after Customs and Border Protection discovered the birds sewn into plastic tubes in his underwear, federal prosecutors said.

Alberto Hernandez Castillo entered Miami International Airport on Sunday after he said he was visiting family in Cuba, according to court documents from the U.S. Attorney for the Southern District of Florida.

Hernandez Castillo told CBP agents that he did not bring any animals or wildlife into the U.S. from his trip; however, the agents "observed an unexplained bulge on the front of [his] pelvis/waist area and noted that he appeared nervous," according to the court documents.

Officers brought Hernandez Castillo to a secure area and performed a pat-down, and that's when they discovered six plastic tubes that were sewn into his underwear with live birds inside, the U.S. Attorney said.

Eight of the birds were yellow-faced grassquits, while two were blue grosbeaks, according to investigators.

Hernandez Castillo allegedly told officers the birds were for his "personal use," according to the court documents.

The U.S. Attorney said he was charged with smuggling goods into the U.S. The U.S. Fish and Wildlife Service said it is also investigating the incident.

ABC News reached out to Hernandez Castillo's public defender but did not receive a response. The birds' status was also unknown.