The ninety-minute tour started at the Blätterlaube, the university's near-natural community garden run by the SUSTAIN IT! and Blühender Campus initiatives. From there, the route wound through species-rich areas of the Dahlem campus to the Henry Ford Building, passing green roofs and unmown meadows that show how deliberately designed green spaces can create habitat for insects.

Since 2020, butterflies have been recorded weekly on campus using Germany's most widely applied method, transect-based butterfly monitoring. Dr. Rebecca Rongstock explained how this method works, what the collected data reveal about local biodiversity, and what caterpillars and butterflies need at each stage of their life cycle.

Armed with nets and viewing containers, the group spotted several butterflies along the way, which were carefully caught, identified, and released again — among them a Common Blue. The walk also covered which plants serve as food sources and egg-laying sites for different species. Other insects crossed the group's path as well, including ladybirds and, most likely, wasps and other flower-visiting beetles.

Plants themselves were also in focus. One especially memorable stop was St. John's Wort: rub its yellow petals between your fingers, and a blood-red juice comes out — a trait that has earned the plant folk names like "blood herb" or "John's blood." According to legend, the plant is said to have sprung from the blood of the beheaded John the Baptist; fittingly, it traditionally begins to bloom around St. John's Day on June 24, just days after the walk took place.

The afternoon made clear how much biological diversity lies hidden in the campus's seemingly unremarkable green spaces — and how simple measures like unmown areas and near-natural planting can actively support biodiversity in the city.