Nest-site fidelity of the European pond turtle Emys orbicularis (LINNAEUS, 1758) (Testudines: Emydidae) in western Poland

Abstract

nests of the European pond turtle Emys orbicularis (L.) were marked in the valley of the Ilanka river (Ziemia Lubuska, western Poland) in the years 1999-2006. 54 nests built by 16 marked females were located in a relatively small area. The remains of 5 other nests, belonging to unknown females and damaged by predators were found in 3 lo- calities in the vicinity of the main study area. 3 out of all marked females laid eggs once, the remaining 13 females 2-7 times. Cases when females laid eggs at least two times were taken into account i.e. 51 nests. Females laid eggs on steep, sunny mid-forest clearings with areas of 375 m 2 -1170 m 2 and situated at a distance of 69-83 m (aver. 77 m) from wa- ter bodies. Apart from the nesting grounds studied, 5 disturbed nests mentioned above were located at a distance of 150-270 m from water bodies. The distance between nests was 0.75-53.9 m (aver. 8.8 m). Most females consistently, each year opted for the same nesting sites (nests) as previous years. Successional vegetation growth and overshadow- ing of the clearings led to the use of locations in nearby areas. Once overshadowing was eliminated, females returned to locations in which they had been observed previously.