Simplify the following text for a Grade 10 native English-speaking person.
Original: Extremely rare sightings of whooping cranes have been recorded , however only three examples of this species are known to live in the Rocky Mountains , out of 385 known worldwide .
Simplified: Extremely rare sightings of whooping cranes have been recorded ; only three examples are known to live in the Rocky Mountains , out of 385 known worldwide .