A lifelong floater: the Red Kite female that never met a mate

Abstract

ABSTRACT The Red Kite Milvus milvus is endemic to the western Palearctic. While the largest breeding population is in Germany, the population density decreases substantially from central to eastern Europe. In 2015, we tagged two young Red Kite females with telemetry loggers in an area with very low kite density in the northeastern part of Slovakia. One of these females failed to breed over her seven-year lifespan. After leaving her post-fledging area she never returned. During her first two years, she undertook two exploratory flights to Croatia and Romania, but remained exclusively in southwestern Slovakia and northeastern Hungary over the rest of her life. Throughout this period, she always wintered alone and no other Red Kites were ever observed in her wintering grounds. During the pre-breeding period (March–April), she remained outside the area that held breeding kite pairs, and there were no signs of breeding based on her positions during the breeding season. This seven-year-old is the oldest Red Kite floater recorded to date. Owing to the low density of Red Kite breeding pairs in Slovakia and Hungary, it is likely that she was unable to find a suitable mate prior to the beginning of the breeding season. In such areas, the role of floaters may prove critical for the persistence of low-density Red Kite populations.