Former PC Michael Upson kept detailed records of his egg collection at his home in Suffolk
A police constable amassed a collection of 649 rare birds' eggs by stealing from nests, often while on duty for Suffolk Police, a court has heard.
Michael Upson, 52, travelled across the UK to collect eggs, but most were taken from areas near his home in Halesworth, Norwich Crown Court heard.
He admitted having the eggs in his possession, contrary to the Wildlife and Countryside Act 1981.
Upson, who has since retired, is yet to be sentenced.
The eggs were found at his home in Sotherton during a raid by police officers and investigators from the Royal Society for the Protection of Birds.
He kept detailed notes describing how and where he gathered them, including instances when he was working on nightshifts.
"... There were no people about and the darkness gave me some cover," he wrote in one diary extract.