TAIPEI (CNA) -- The Chinese crested tern (Thalasseus bernsteini), a rare bird on the brink of extinction, has been spotted again this year on the Taiwan-held Matsu Islands -- its original habitat -- researchers said Friday.



The return of the endangered bird, a tern in the family Laridae, to Matsu for four consecutive years means the bird has a regular migratory path and has grown a sense of affinity with the environment on the islands, researchers at National Taiwan University said.



The Chinese crested tern spotted in Matsu was identified as A74, which flew back to Matsu after being released by researchers into the wild in July 2015 with a white and blue tag.



It is a critically endangered species, with only 100 estimated to still exist in 2000.



It used to nest in a greater crested tern colony on an islet in the Matsu Islands and head south to winter in the Philippines.