to these mountains would always be found there. According to the Encyclopedia of Oklahoma History and Culture, the refuge failed in its attempt to reintroduce the American pronghorn antelope, bighorn sheep, and the prairie chicken. The conservation of bison has become an ongoing, diverse effort. and the refuge was important in saving the American buffalo from extinction. In 1907 the American Bison Society transported 15 bison, six bulls and nine cows, from the Bronx Zoo. On arrival, the Comanche leader Quanah Parker and a host of other Indians and whites turned out to welcome the bison. At that time, bison had been extinct on the southern Great Plains for 30 years. The bison herd now numbers about 650 on the refuge. In fall, bison in excess of the carrying capacity of the refuge were auctioned off but this practice was ended in 2020 when the refuge joined in the Bison Conservation Initiative. The 2020 Bison Conservation Initiative by the Department of the Interior has five central goals: wild, healthy bison herds; genetic conservation; shared stewardship; ecological restoration; and cultural restoration. It strengthened mechanisms for delivery of bison to Native American tribes from federal herds. In 1973, the refuge aided bison conservation by donating three bison to the Fort Worth Nature Center and Refuge. The refuge is home to many species of birds, and it is one of the remaining homes of the recently delisted black-capped vireo. Flora The refuge is ecologically diverse, with prairie, ravine, and mountain plant communities. The many exposed granite boulders make exceptional habitat for a particularly photogenic, chartreuse green lichen known as "Pleopsidium flavum." Portions of the refuge contain scrubby forest of mixed oak varieties. A disjunct population of bigtooth maple is found here, from the nearest natural population in West Texas. Recreation There is no admission charge. Public use areas on the refuge total . The remaining has guided tours only. A visitor center and bookstore displays art and has exhibits illustrating the four major habitats found on the refuge: Rocklands, Aquatic, Mixed-Grass Prairie, and Cross Timbers. The refuge is a popular destination for recreational activities. Rock climbing is overwhelmingly popular, but visitors also enjoy hiking, camping, fishing, bird and wildlife watching, and photography. The refuge has an extensive trail system, including about 15 miles of official trails and unofficial trails. Many of these trails lead to climbing routes. The area became popular for rock