TV naturalist Chris Packham was questioned by police officers after an angry confrontation with armed hunters.
Mr Packham, who lives in the New Forest, had spent the past week on the Mediterranean island of Malta, highlighting the plight of migrant birds which are shot in their thousands by hunters.
He has been taking video footage, and posted video footage of a heated exchange with hunters during which they repeatedly demanded that he stop filming.
Mr Packham, who presents the BBC's Springwatch, was called in for questioning by Maltese police on Saturday.
He said it was because lawyers from the hunters' federation FKNK asked police to investigate an alleged privacy breach and defamation.
Although he said he was threatened with arrest if he released a statement to the police, he was released after five hours of questioning.
He said afterwards: “I did everything I could to be cooperative with the police.”
Packham says as many as 10,500 hunters armed with shotguns gather on the island every year for a three-week shooting season as migrant birds return to the UK from North Africa.
Among the birds that travel back to the UK and northern Europe via Malta are barn swallows, cuckoos, marsh and pallid harriers, kestrels, ospreys and grey herons.
Chris and a team of fellow environmentalists have put together five video diary entries on the hunting and their confrontations with the hunters, which are available on YouTube.