Butterfly Conservation in the Zoo

Caterpillar of the critically endangered eastern baton blue (Pseudophilotes vicrama). Photo: Miroslav Bobek, Prague Zoo

For many years, we have been working to create suitable conditions for the return of butterflies to the zoo grounds. Regular clearance of shrubs and trees—for instance along the Zakázanka path, which runs through the Skály v zoologické zahradě (Rocks in the Zoological Garden) Natural Monument—plays an important role, as does sheep grazing on the Sklenářka site, a registered significant landscape feature behind the giraffe enclosure. Our gardeners also contribute by sowing seed mixtures rich in forbs when establishing wildflower meadows in the zoo grounds, and by planting nectar-rich species in the flower beds to attract pollinators.

One of the noteworthy butterfly species found at Prague Zoo is the chequered blue (Scolitantides orion). This endangered species of the Czech fauna, whose numbers are declining nationally, has found suitable conditions on the sunny slopes along the Zakázanka path, where a small population has persisted for many years. To support it further, in 2022 we planted grand stonecrop (Hylotelephium maximum)—an important host plant for the species—at several additional sites within the zoo, such as on the green roof of the Dja Reserve house and on the rocky slopes among the vineyards above the Rákos’ House.

Chequered blue (Scolitantides orion). Photo: Marek Vojtíšek

Even rarer is the eastern baton blue (Pseudophilotes vicrama). It became extinct in Moravia around the year 2000 and survives in Bohemia only at a handful of remaining sites, where it is also gradually disappearing. It is therefore protected by law as a critically endangered species. Its preferred habitat consists of stony dry grasslands with patches of wild thyme. At Prague Zoo the eastern baton blue was regularly recorded until 1994, particularly on the slope below the Sklenářka building. However, the gradual encroachment of scrub and tall grasses made sightings increasingly sporadic, and the species was last observed here in 2004. Since then, we have succeeded in restoring the dry, sunny grasslands with thyme cushions—thanks in part to targeted sheep grazing, which also helps maintain suitable conditions for the critically endangered European ground squirrels present on the site. The butterfly’s return, however, required some assistance, as the nearest surviving populations were too far away for natural recolonisation to occur. In cooperation with the conservation organisation Třesina, we therefore undertook the necessary steps for its reintroduction and, from 2021 onwards, have been gradually releasing pupae and larvae onto the meadow at Sklenářka to re-establish a wild population of eastern baton blues at Prague Zoo. The project also includes thorough monitoring.

Eastern baton blue (Pseudophilotes vicrama). Photo: Marek Vojtíšek

Further reading:

• Macrolepidoptera of Prague Zoo
• Eastern Baton Blue in My Butterfly Collection
• The Butterflies of Sklenářka exhibition (2019)