The squawking bugle-like call of the whooping crane can no longer be heard in the woods of Maryland's Patuxent Research Refuge.
The last of a flock of 75 cranes left the Laurel site on Wednesday, the U.S. Geological Survey said.
The departure marks the end of the refuge’s 52-year-old breeding program, which biologists say helped save the still-vulnerable population of massive birds from extinction.
The effort began in the 1960s with a one-winged bird named Canus, at the time one of fewer than 50 whooping cranes alive.
The whooping crane population now numbers about 700, in large part owing to biologists at the Patuxent refuge who spent years figuring out how to get whooping cranes to successfully reproduce. That included developing artificial insemination methods and dressing biologists in crane costumes while raising young cranes in captivity.
USGS officials brought the program to an end saying that further research into crane breeding was no longer needed, and that the species should be handed over to zoos and other wildlife centers to carry out the lessons biologists learned at the Patuxent refuge.
“Whooping cranes are still endangered, but the overall population has grown more than tenfold in the last 50 years since Patuxent’s program began,” said John French, a USGS biologist and director of the USGS Patuxent Wildlife Research Center. “The end of the USGS program is an indication of just how far we’ve come in our research and recovery efforts and is a tribute to the numerous researchers from the U.S. Geological Survey and numerous collaborators and partners who dedicated five decades to help chart the course for the recovery of this iconic species.”
The cranes were transferred to research institutions and zoos in Virginia, Florida, Texas, Oklahoma, Nebraska, Louisiana and Canada.