Wicken Fen has been known since the 19th century as special place for wildlife, especially for rare plants and insects. Charles Darwin is known to have visited the Fen to collect beetles and moths when he was studying at Cambridge University in the 1820s. Naturalists were originally drawn to Wicken because of its species richness and the presence of rarities. Wicken was one of the very few places in Britain where you could see swallowtail butterflies and marsh moths. From about 1860, Wicken Fen became an important site for the study of natural history, and particularly entomology, because other fens in the area were drained at this time.

There are fascinating accounts of the visits of Victorian entomologists (people who liked to study and collect insects) to Wicken in the journals of that time. These accounts give an insight into the great efforts these people made to get to Wicken and study the insects. They also helped to support the local fenland people by staying at the pubs, paying for guides and for specimens of the insects they wanted.

Extract from the writings of Dr John Henry Salter, in a Natural History Diary, Volume 2 (1891), in the National Library of Wales and transcribed by Adrian Fowles.

"5 September 1891 - started at 7.30 for an excursion to Wicken Fen, reaching Soham at 9.24 … our field path brought us to Wicken Village. [On the Fen] … we sighted a native looking about as if caterpillar hunting, so bore down on him. He opens his collecting box - a ground coffee tin - and we get our first sight of a full-grown specimen of the longed for larva. The swallowtail was soon in our possession as the result of a small commercial transaction in which 3d changed hands. The man, whose name was Fuller, makes a living in the Fen during the summer months, first by bird nesting and then by caterpillar hunting. While we were lunching Fuller came along and when questioned as to his luck told us he had taken several. This proved to be 25 or 30. We bought three additional Machaon at 2d each. Fuller told us that he collected some thousands in the course of a summer, his season beginning at the end of June. At this time of year he has more orders than he can fill. He does not notice any increasing scarcity from year to year, never catches the adult butterfly itself except for a special order."