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.