Ecological Role of the Common Pheasant (Phasianus colchicus) in Maintaining Tick Populations in Croatia.

Ticks are obligate hematophagous ectoparasites of public health importance, acting as vectors of numerous pathogens affecting wildlife, domestic animals and humans. Although birds play an important role in tick ecology and dispersal, information on tick infestations of pheasants in Europe remains limited. This study investigated the prevalence, species composition, developmental stage structure and haplotype diversity of ticks infesting pheasants in Croatia using ecological, morphological and molecular approaches. During the hunting seasons, 255 pheasants from continental and Mediterranean regions of Croatia were examined. Ticks were collected from harvested pheasants and road-killed individuals, morphologically identified, and representative specimens were molecularly confirmed. Overall, 213 pheasants were infested, resulting in a prevalence of 83.5%, and a total of 1103 ticks were collected. Six tick species were identified, with Ixodes ricinus dominating the tick community (80.1%). Molecular analyses confirmed the occurrence of several closely related Mediterranean Ixodes species, including Ixodes festai and Ixodes ventalloi. Nymphs predominated (78.2%), highlighting the importance of pheasants as hosts for immature tick stages. Significant geographical differences were observed. Continental localities were dominated by I. ricinus, whereas coastal and island regions showed significantly higher tick species diversity. Mean tick abundance per pheasant was significantly higher in Mediterranean regions. Male pheasants exhibited higher infestation prevalence and intensity than females. The marked regional differences highlight the influence of Croatia's biogeographical heterogeneity on tick community composition. These findings demonstrate that pheasants serve as important hosts for diverse tick species and likely contribute to the maintenance of local tick populations, thereby providing a valuable baseline for future surveillance of tick-borne pathogens in Croatia.