Jakarta, June 11 -- Indonesia's Forestry Ministry said a female Sumatran elephant calf was born in Riau's Tesso Nilo National Park, marking another milestone in efforts to boost the critically endangered species' population.

Heru Sutmantoro, head of the Tesso Nilo National Park Agency, said the calf was discovered at about 7:30 a.m. local time by mahouts in a forested area near the Sumatran Elephant Conservation Resort in Pelalawan District.

Field observations indicated the calf was likely born around 4:00 a.m. local time, shortly before dawn, Heru said on Wednesday.

Examinations by veterinarians found the female calf to be healthy, active, free of physical defects and able to nurse normally from its mother.

The newborn is the fifth c...