The black-necked crane, a symbol of fidelity on the Qinghai-Tibet Plateau, and a species historically perceived as loyal, are often seen in pairs in wetlands or highland barley fields.

However, a recent groundbreaking study has shattered this long-held belief, unveiling that the traditional notion surrounding these majestic birds is nothing more than a human illusion.

The study, conducted by a team of Chinese researchers, sheds light on the mysterious mating strategies and group dynamics of the black-necked crane (Grus nigricollis), a species mainly found on the Qinghai-Tibet Plateau.

Utilizing advanced DNA analysis techniques and meticulous field observations, the study challenges conventional views of crane monogamy and unveils intriguing insights into the species' reproductive behavior.

The research, spanning four years and focusing on breeding pairs in important bird habitats such as Flower Marsh and Nalecho Marsh in Zoige Wetland National Nature Reserve in Sichuan province, revealed a complex tapestry of mating strategies among this wetland species.

Contrary to expectations of strict monogamy, the study found a significant tendency for extra-pair copulation, with no pair maintaining monogamy throughout the observation period. Notably, the extra-pair fertilization rate was found to be 16.6 percent, a figure higher than in many other territorial bird species.

The research, titled "Mechanisms of enhancing genetic fitness in non-kinship-based groups: insights from black-necked cranes", was published online on Thursday on the open access, peer-reviewed science journal, The Ecological Indicator.

"Our findings are kind of contrary to our traditional understanding," said Li Yuhang, a researcher from Sichuan University in Chengdu, Sichuan province, who is one of the article's two first authors. "The crane is considered a symbol of fidelity, not only in China but also in Bhutan and India."