A man has been arrested after a number of dead owls were found in a freezer at a house in Essex, together with 25 stuffed birds.
The 49-year-old man was detained on suspicion of trading in endangered species following a search of his property in Stanford-le-Hope.
The frozen birds are being examined to determine how they were killed.
It follows a joint inquiry involving the National Crime Agency (NCA), Border Force and National Wildlife Crime Unit.
Ian Truby, from the NCA's Border Policing Command, said: "This joint investigation has so far identified around 150 endangered birds that we suspect have been sold without the correct trade certificates or export permits.
"Unregulated imports or exports of animals can harm the survival of rare species. That is why the law around moving them is so strict."
In addition to his arrest on suspicion of trading in endangered species, the man was also detained on suspicion of evading customs regulations relating to endangered species.
He was released on bail until 7 January.