The Fish and Wildlife Service's Winter Whooping Crane Survey estimates there's a total of 279 whooping cranes, including 257 found within the primary wintering grounds and 22 beyond that area. Service personnel conducted seven surveys of the primary wintering grounds of the Aransas-Wood Buffalo flock, the last remaining wild flock of whooping cranes. With the help of the Texas Parks and Wildlife Department's Texas Whooper Watch and other observers, additional sightings suggest at least 22 additional birds outside the primary wintering grounds. Last year, the count was 267 birds. The birds begin arriving at their Texas wintering areas in mid-October and leave for their summer homes the end of March.
You can read about the survey and more at this address.