The recent shooting of two endangered whooping cranes is a setback for efforts to reintroduce the rare birds to Louisiana, but researchers say they plan to move forward with the release of a second contingent of young cranes later this year.

State wildlife officials say two boys ages 16 and 13 are suspected of shooting and killing the birds on Sunday in Jefferson Davis Parish.

State Department of Wildlife and Fisheries spokesman Bo Boehringer said this week that the case remains under investigation and charges are pending.

The two cranes were among a group of 10 released in February at the state’s White Lake Wetlands Conservation Area in Vermilion Parish, the same general location where the last known whooping crane in Louisiana was documented in the 1940s.

There have been four confirmed deaths: the two shot on Sunday; one bird believed to have been killed by a predator; and another that was euthanized because of a respiratory infection, said state Wildlife and Fisheries biologist Sara Zimorski, who is helping oversee the joint federal-state whooping crane reintroduction project.

She said a fifth bird is missing and presumed dead.

“This was certainly a pretty significant setback to lose two birds,” she said of the shootings.

Zimorski said that before the loss on Sunday, researchers were pleased with the survival rate of seven out of 10 birds.

She said the goal of the project’s first year was a survival rate above 40 to 50 percent.

“This is very much an experiment,” Zimorski said. “… We fully expected some mortality.”

She said the reintroduction project is continuing on schedule, and there are 16 crane chicks being reared at a federal wildlife center in Maryland that are expected to be released at White Lake by the end of the year, assuming all they all survive the early stages of life.

“If everybody stays healthy, we could see as many as 16,” Zimorski said.

Of the remaining birds that were released earlier this year, researchers are still tracking four of them with transmitters.

The transmitter recently stopped working on a fifth crane, but the bird has been spotted recently and is thought to be still alive, Zimorski said.

The birds were first kept in a netted pen and then later release into one-and-a-half acre fenced area that provided a predator-free zone while allowing the birds to come and go as they pleased.

Of the four birds with working transmitters, two have remained in the White Lake area, one is in Acadia Parish and the other is in Jefferson Davis Parish, Zimorski said.

She said the roaming birds have been attracted to the rice and crawfish fields of south Louisiana, which was a bit unexpected.

“I think some Louisiana folks probably thought they would have stayed in the marsh,” Zimorski said.

The cranes were initially offered a food supplement in the form of pellets but have quickly taken to the native cuisine, dining on frogs, fish, baby turtles and other marsh life, she said.

The young cranes had been exposed to some natural food sources while being raised in captivity, Zimorski said, but crawfish was a new flavor.

“Crawfish they picked up on immediately,” she said. “… If they see something moving, there is a curiosity to go after it.”

The effort at White Lake is part of a larger initiative to revitalize the whooping crane, a massive bird that can grow up to 5 feet tall with a 7-foot wingspan.

Other reintroduction efforts in the United States have had mixed results with some considered successful while others have been abandoned.

There are an estimated 400 whooping cranes in the wild, according to figures from the U.S. Fish and Wildlife Service.

The loss of whooping cranes to gunshots is not a problem peculiar to Louisiana.

The Fish and Wildlife Service has reported four other whooping crane shooting deaths over the past year, three in Georgia and one in Alabama, as well as a second suspected shooting in Alabama.