Citizen scientist in action: first evidence of the non-native spiny-cheek crayfish Faxonius limosus (Rafinesque, 1817) as a trophic source for water-related birds

We report the first European record of five shorebirds (Anas platyrhynchos, Fulica atra, Larus michahellis, Melanitta fusca, and Podiceps cristatus) preying on the non-native spiny-cheek crayfish (Faxonius limosus) in Lombardy (Northern Italy). This crayfish is considered an invasive alien species, rapidly spreading all over the country, primarily in northern regions. These first observations of predation by bird species evidenced the availability of F. limosus as a new trophic resource, even for mostly herbivorous species, such as F. atra and A. platyrhynchos. In this note, we would also highlight the role of citizens in providing further records of new interactions among native and non-native species.