Endangered tern threatened by crossbreeding

The Chinese crested tern, the world's most endangered tern species, could become even rarer because of crossbreeding with a more abundant sister species, Chinese ornithologists have warned.

The hybridization of the two closely related species may erode their gene pools and accelerate the rate of the rare bird's extinction, said Chen Shuihua, deputy director of the Zhejiang Museum of Natural History.

He said his museum in Zhejiang province and two other institutes collected noninvasive DNA samples from five Chinese crested terns for genetic conservation studies and observed hybridization occurring between the rare bird and the great crested tern.