Thieves have made off with more than £17,000 worth of clap pigeon shooting equipment from a remote site near Alfriston.
Police believe a four-wheel-drive would have had to have been used to make off with the eight Promatic traps over the weekend.
Club officials found the metal container where they were kept had been forced open and a padlock and chain securing the metal gate at the entrance to an access track had been removed.
PC Ian Grabiner, of the Wealden Neighbourhood Response Team, said: "This, coupled with the rough nature of the track, suggests an all-terrain vehicle may have been used.
"We would like to hear from anyone who saw any suspicious vehicles, people or activity in the Winton street area of Alfriston over the early part of the weekend, prior to the theft being discovered shortly before 7am on Sunday (26 June).
"Any other information as to what became of the traps, similar to those shown in our photograph, would also be welcome."
Anyone able to help should e-mail firstname.lastname@example.org or phone 101, quoting serial 414 of 26/06.
Alternatively, they can contact the independent charity Crimestoppers anonymously on 0800 555 111.