Expanding the range of black grouse Tetrao tetrix in northern England through translocating wild males

Black grouse were once widespread in England, but have declined over the past 150 years due largely to habitat changes. In 1998, 773 males remained and following the instigation of conservation measures population size increased to 1029 in 2006, but population range remained similar. We hypothesized that range expansion was limited by the short dispersal ranges of males (up to 1 km) relative to females (up to 19 km), resulting in yearling females dispersing into areas without males. We tested this hypothesis by moving males to establish new leks and to stimulate range expansion. Three release sites were chosen beyond the southern edge of the male range, but were within the perceived dispersal distance of females, and where habitats were considered suitable and generalist predators were controlled. Between 2006 and 2010, 17 males were released at the first site, and a further 18 and 27 respectively at two sites between 2011 and 2014. Males were caught at night, fitted with radio-transmitters and hard relea...