The MigraBats project is tagging forest bats to study their seasonal and migratory movements, as well as their roosting areas. The project has discovered new populations in the Aran Valley, including some threatened species.
The Forest Science and Technology Centre of Catalonia (CTFC), in collaboration with the Max Planck Institute in Germany, continues to advance research and conservation of bats, with a special focus on forest species. This August, within the MigraBats project —part of the EndesaBats program— researchers carried out two capture and tagging sessions in the Aran Valley to study the seasonal and migratory movements of large forest bats, such as noctules.
The activities took place in two areas of special interest: Portillón and Artiga de Lin. In total, three giant noctules (Nyctalus lasiopterus) were captured, one of the largest bats in Europe and considered threatened in Catalonia. The individuals were fitted with tracking transmitters that will provide data on their movements over the coming weeks, offering key insights into their migratory routes and roosting areas.
A biodiversity hotspot for bats
Artiga de Lin, with its mature beech forests, mountain streams, and natural ponds, is a highly valuable habitat for many bat species. The capture sessions confirmed their richness: in a single night, 12 different species were identified, representing 60% of all forest bat species and 40% of the bat species present in Catalonia.
Among the most notable findings were new records for Catalonia and the Pyrenees of the Alcathoe whiskered bat (Myotis alcathoe), as well as two first records for the Aran Valley: the alpine long-eared bat (Plecotus macrobullaris) and the parti-colored bat (Vespertilio murinus). All three are threatened species: one listed as “Endangered” and the other two as “Vulnerable” in the Catalog of Threatened Fauna of Catalonia.
More than insectivores: indicators of environmental health
Beyond their essential role in controlling insect populations, bats are considered excellent indicators of ecosystem health. Their presence and diversity in Artiga de Lin not only confirm the quality of high-mountain habitats but also raise the conservation interest of the entire area to the highest level.
Through the monitoring of tagged individuals and the data collected, the MigraBats project will provide new insights to help improve conservation strategies for these species on the Pyrenean and European scale.
Last modified: 5 September 2025
