Helminth fauna of birds in the Smolny National Park and adjacent territories (Republic of Mordovia)

We studied the helminth fauna in birds 35 species of birds from Passeriformes, Piciformes and Caprimulgiformes in the Smolny National Park and its surroundings in 2018-2022. In total, 23 species of helminths were identified in birds: 8 trematodes, 10 cestodes and 5 nematodes. We presented taxonomic position, host range, rates of infection, and geographical distribution for each helminth species. The most diversity of helminth fauna is in Turdus phylomelos (10 species) and Turdus merula (7). In Parus major and Fringilla coelebs, six and five species were recorded, respectively. The helminth faunas in Anthus trivialis and Ficedula hypoleuca are poor (4 species each). In total, three species of parasites were found in Erithacus rubecula, Poecile montanus, Sylvia atricapilla, Ficedula albicollis and Dendrocopos leucotos. One species, the trematode Morishitium polonicum, was revealed in birds of the Russian fauna for the first time (in Coccothraustes coccothraustes and T. merula). Four cestode species, Capiuterilepis naja, Birovilepis sobolevi, B. spasskayae and Monopylidium passerinum were recorded for the first time in the Middle Volga region. New hosts were identified for nine species of parasitic worms. One species, the nematode Physocephalus sexalatus, found in the birds of the Smolny National Park and its surroundings have veterinary and medical significance as potential pathogen of dangerous helminthiasis.