The ups and downs of the Tree Frog in the Leemputten nature reserve in North Brabant The Common Tree Frog (Hyla arborea) was once common in the province of North Brabant, especially in the surroundings of Tilburg. However, from the 1960s onwards, nearly all the populations died out as a result of habitat degeneration. One of the last remaining populations was located in the nature reserve de Leemputten near Udenhout not far from Tilburg. From 1976 onwards, the number of calling males was estimated annually in the breeding season. In approximately five years their number decreased significantly and it was clear that the population was threatened with extinction. The last calling male was recorded in 1981, while in the following years, only one or no tree frogs were sighted in the land habitat. In order to prevent the extinction of one of the last remaining populations of Hyla arborea in North Brabant, a habitat restoration plan was carried out by the nature conservation organisation Brabants Landschap. At the same time, a breeding program was started and large tadpoles and juveniles were introduced in 1987, 1988 and 1989. As a result of this program the first calling male was recorded in 1989. Natural reproduction was recorded again in 1990 and from this year onwards, the number of calling males increased significantly. Since then, calling males and juveniles have been recorded almost every year with maxima of up to 200 calling males and 800 juveniles. To protect this population in the long term, Brabants Landschap is investing in expanding the nature conservation area and also creating a habitat corridor to the nearby population of the Tree Frog in De Brand (RAVON 49).