Background: Previous studies on the tick infestation of birds in the Carpathian Basin focused on songbirds (Passeriformes). Thus, the primary aim of the present work was to extend the scope of previous studies, i.e. to include aquatic (water-associated) bird species in a similar context, especially considering that these birds are usually long-distance migrants. Methods: Between March 2021 and August 2023, 11,919 birds representing 126 species were checked for the presence of ticks. From 352 birds belonging to 40 species, 905 ixodid ticks were collected. Tick species were identified morphologically and/or molecularly. Results: Ticks from avian hosts belonged to seven species: Ixodes ricinus (n = 448), I. frontalis (n = 31), I. festai (n = 2), I. arboricola (n = 36), I. lividus (n = 4), Haemaphysalis concinna (n = 382) and Dermacentor reticulatus (n = 2). Nymphs of I. ricinus occurred with a single activity peak around March–May, whereas its larvae typically infested birds in May, June or July. By contrast, H. concinna usually had its activity maximum during the summer (nymphs in June–July, larvae later in July–August). Interestingly, two ornithophilic species, I. frontalis and I. arboricola, were most active around winter months (between October and April). A significantly lower ratio of aquatic birds was found tick-infested than songbirds. Several new tick–host associations were revealed, including I. ricinus from Greylag Goose (Anser anser) and D. reticulatus from Great Egret (Ardea alba) and Sedge Warbler (Acrocephalus schoenobaenus). Ticks were collected for the first time in Europe from two species of predatory birds as well as from Little Bittern (Ixobrychus minutus). Bird species typically inhabiting reedbeds were most frequently infested with H. concinna, and most ticks localized at their throat, as opposed to forest-dwelling avian hosts, on which I. ricinus predominated and ticks were more evenly distributed. Conclusions: In the evaluated region, aquatic birds appear to be less important in tick dispersal than songbirds. However, newly revealed tick-host associations in this category attest to their hitherto neglected contribution. The results suggest that the habitat type will have significant impact not only on the species composition but also on the feeding location of ticks on birds. Graphical Abstract: (Figure presented.)

Tick infestation of songbirds has been extensively studied at global and regional scales but relevant data on birds of prey remain scarce and fragmentary. Raptors are of particular epidemiological relevance because their large size, wide-ranging movements and nesting habits may facilitate long-distance dispersal of ticks, and endophilic tick species (e.g. from prey animals) may even persist in their re-used nests. In this study, we aimed to compensate for the lack of comprehensive data in this context. First, more than 1800 birds of prey were examined at 61 sites in Central and South-Eastern Europe, encompassing both continental and Mediterranean climatic regions. Ticks (n = 839) were obtained from 98 birds representing 13 raptor species from three avian orders. Twelve tick species were identified, the most abundant being Rhipicephalus turanicus, Haemaphysalis concinna and Ixodes ricinus. Several previously unknown tick–host associations were revealed. Molecular-phylogenetic analysis showed that sequences of Ixodes arboricola from Tawny Owls (Strix aluco) clustered separately from other conspecific sequences, raising the possibility that Ixodes strigicola Schulze and Schlottke, 1929 is a valid species. Owls proved to be the most heavily tick-infested, particularly Eurasian Eagle-Owl (Bubo bubo) nestlings. Endophilic and rodent-associated tick species were significantly more common on owls and on bird species nesting in cavities or buildings, whereas diurnal raptors were predominantly infested by generalist and exophilic ticks. These patterns highlight the importance of nesting ecology and prey composition in shaping tick assemblages on raptors. The results provide novel insights into tick–raptor associations, contribute new records of tick species from birds of prey, and improve our understanding of the role of raptors in tick maintenance and dispersal which appears to be particularly important in the case of cavity-nesting species. In addition to field sampling, a comprehensive database from nearly 150 published sources revealed that 32 tick species have been reported from birds of prey in the Western Palearctic to date.