The black-necked crane is China's rare national treasure and only breeds on the Qinghai-Tibet Plateau. Through the efforts of environmental workers and volunteers who provide food in times of shortage, the population of black-necked cranes has increased from 200-300 to over 8,000 in 20 years. The government has established nature reserves and planted crops specifically for the cranes. Black-necked cranes form lifelong monogamous pairs and will grieve or commit suicide if their partner dies.