Founded in 1973, the Balearic Group of Ornithology and Defense of Nature (GOB) was originally formed as a group of bird lovers and watchers, but with time has established itself as a leading force in the fight against the environment destruction and species loss brought about by the rapid transformation of the Balearic landscape. The campaigning work of this non profit organisation has combined the study and analysis of environmental indicators, education and awareness raising, citizen mobilisation and participation and the promotion of agreements, laws and private schemes to safeguard ecosystems and species, especially the most endangered, and preserve the balance between nature and human activity. The biodiversity conservation strategy rolled out by the GOB in the Balearic Islands is anchored on the study of nature, the defence of natural spaces and endangered species and sharing in the management of protected spaces. It also involves assessing the impact of human activities on the natural environment with a view to promoting sustainable alternatives, especially from the standpoint of territorial planning. All this combined with an intense effort to educate and inform about environmental issues in partnership with education centres, town halls and other island authorities. In over 30 years of active existence, the GOB has worked tirelessly for the defence and protection of natural spaces. These efforts were instrumental in securing the creation of seven Natural Parks and one National Park (Cabrera), the passage of the Natural Spaces Act (1991) and Minorca’s designation as a Biosphere Reserve. The group has also worked to protect a further twenty sites of outstanding natural value along the Balearic coasts. Its activities on behalf of emblematic island species are also rich in success stories, like the preservation of the black vulture and the red kite. Finally, to remark its influence in mobilising social opinion on the islands around the mitigation of human environmental impacts.