LINCOLN, Neb. (AP) — Nebraska wildlife officials are asking the public to keep an eye out for rare whooping cranes over the next several weeks.

The Nebraska Game and Parks Commission says the continent’s entire population of whooping cranes is expected to migrate through Nebraska over the coming weeks. Information on sightings is used for whooping crane conservation and recovery efforts.

The rare cranes have features that distinguish them from the more common Sandhill crane. Whooping cranes are approximately 5 feet tall and fly with their neck outstretched. Adults are all white with the exception of black wing tips and reddish-black facial pattern.

Whooping cranes were near extinction in the early to mid-20th century. Through conservation efforts, the birds’ numbers in the wild have increased slowly, now ranging from around 430 to 500.