They were held on suspicion of aggravated trespass after police responded to reports of horns being blown and individuals straying from a public footpath.
Gloucestershire Police said the four refused to give the arresting officer their details after they were stopped in the Forthampton area of the county at around 2am on Friday.
A short time later they supplied the information and were released, police confirmed.
A force spokesman said on Friday: “At around 2am this morning police responded to reports of horns being blown and individuals straying from a public footpath in the Forthampton area.
“Four people were arrested on suspicion of aggravated trespass and refused to give officers their details. A short while later they responded to the officer’s request for their information and were de-arrested at the scene. They were not taken to custody.”
Queen guitarist Brian May will be in the county later to visit the cull zone.
May, a leading opponent of the cull, will be in the Tewkesbury area to meet residents and discuss their views on the pilot taking place on their doorstep.
The music legend, who is a member of the Team Badger campaign, will also join a peaceful night walk being staged by anti-cull activists.
An online petition that May started against the pilots has become the most signed on the official Government website, with nearly 300,000 people having added their name.
“It remains a clear indication of the depth and continued growth of public outrage over Environment Secretary of State Owen Paterson’s plan to kill thousands of badgers in the UK,” May said.
“It’s also now the most unpopular thing this Government has ever done, if their own petition website is any measure.”
The NFU confirmed that the west Somerset cull began last week and opponents believe the shooting in west Gloucestershire started on Tuesday night.
The controversial pilots aim to tackle tuberculosis in cattle by killing around 5,000 badgers over a six-week period.