Observations of the ecological and behavioral adaptations of hydrophilic birds in urban areas are essential for preservation of the biodiversity under extreme anthropogenic transformations of the inland and coastal waters on the Crimean peninsula. In the Crimea a little bittern Ixobrychus minutus (Linnaeus, 1766) nest usually on the fresh and brackish water bodies. For the first time this species was found nesting in Kruglaya bay, the overused recreation area in Sevastopol (Black Sea). Our investigation detected factors determining the breeding efficiency, food spectrum, behavioral responses and the duration of stay of the little bittern in the biotope exposed to high anthropogenic load. Visual observations, photography and video recording were conducted five times a week within Kruglaya bay. Two adult I. minutus were observed from July 3 to August 2, and three immature birds – from July 24 to September 7, 2016 in the bay head. The presence of natural shelter (reed beds) and good feeding base contributed to successful breeding of the birds. The main prey were the juveniles of grey mullet, other preys were peacock blenny Salaria pavo, ocellated wrasse Symphodus ocellatus and invertebrates. The little bitterns showed atypical for this species synanthropic behavior: having gradually adapted to the people neighborhood, they allowed the observer’s presence at 4–6 m distance. In August the young birds began demonstrating territorial behavior and in September they flied beyond the bay area. The study has disclosed high adaptive potential of I. minutus to disturbing factors in atypical to this species habitats in the coastal urban area of the Black Sea. The possibility of little bitterns settling in the fragmentary natural landscape (return urbanization) of urban areas on the Crimean coast of the Black Sea is discussed. Presumably, I. minutus can nest in the semi-aquatic growth bordering some Crimean bays including Kruglaya, Streletskaya, Kazach'ya and Sevastopol bays. The fragments of natural landscape allow preserving the biodiversity; for their protection any building activity ruinous to semi-aquatic vegetation in the coastal zone should be banned.
Redescription of Desportesius brevicaudatus (Spirurida, Acuariidae) based on nematodes from Ixobrychus minutus (Aves, Ciconiiformes) from Bulgaria