Whooping Crane Eastern Partnership
Why are the WCEP whooping cranes kept in the pen at the winter release site?
February 13, 2007
For more information, contact:
Joan Garland 608-356-9462,
x142
Rachel F. Levin, (612) 713-5311; 612-309-5760 (cell)
View photos of the whooping crane pen at Chassahowitzka NWR from February 2006 (Operation Migration website)
The Chassahowitzka National Wildlife Refuge, located on Florida’s gulf coast, is over 31,000 acres of salt water bays, estuaries and brackish marshes with a fringe of hardwood swamps along one boundary. The whooping cranes are located in four acres of fenced-in salt marsh. The fencing includes three levels of electric fencing to protect the birds from predators. The primary threat for whooping cranes in this area is bobcats. Within this fenced-in area is a covered food shelter, where the cranes have access to a pelletized food source. There is an oyster bar within this enclosure which serves as the birds’ roost. This four acre enclosure is not top-netted and the birds can fly in and out during the day. This arrangement allows the cranes to forage within as well as outside the pen. At night, the birds are returned to the open pen, through active staff intervention if needed, to roost on the oyster bar within the enclosure for protection from predators.
Connected to this four acre enclosure is a smaller pen with flight netting over the top. This smaller pen also includes three levels of predator-proofing electric fencing. This smaller pen is used to house the juvenile whooping cranes when older whooping cranes, from previous years’ releases, are present at the pensite. If the juvenile cranes are not housed in the smaller pen while the older birds are present, the older birds are often aggressive to the younger ones, keeping them from the feeders and occasionally attacking them. This aggression has forced younger birds out of the safety of the pen making them vulnerable to bobcat predation.
The older whooping cranes will only stay at the pensite as long as they have access to the feeders. When these older cranes show up, we remove the feeders from the larger pen and place them under the top-netted pen. The juveniles are housed in this top-netted pen with access to the food until the older cranes disperse inland where foraging is easier.
The Chassahowitzka NWR pensite is located approximately five miles from the mainland and accessible only by airboat. This remote location is in an area of the refuge closed to the public to maintain the strict isolation-rearing protocol, adhered to on this project so the birds will not become accustomed to people and will remain wild.
To ensure the birds don’t become too accustomed to the costumed personnel, we strictly limit our contact with the birds. These precautions are essential to the success of the release; during this winter period, the birds are gradually transitioning to life in the wild. Project staff travel roundtrip via airboat twice a day out to the pensite area. To keep the birds from seeing or hearing the airboat, personnel dock the airboat and then walk in to the actual pensite. It is a challenging hike-- navigating a narrow planked walkway around deep mud and water holes. The staff monitors the birds from a blind, observing behavior and overall health of the birds. The costumed personnel refill the feeders, if needed, check for signs of predators, and ensure the electric fencing is working properly.
Project staff went out to the pensite for the daily pre-dusk roost check on February 1. Since there were older whooping cranes present, the juveniles remained in the top-netted enclosure. Rain and thunderstorms were forecast for that evening, but the level of intensity that actually occurred was not predicted. The storm was the second-deadliest combination of thunderstorms and tornados in Florida history, killing 20 people and causing millions of dollars in property damage. In the six years of this project, the cranes have weathered many thunderstorms in their top-netted pens--at Necedah NWR, while on migration and at the Chassahowitzka NWR pensite. The severity of the storms that occurred that evening were not expected or predicted. The storm reached peak intensity after midnight, and the birds were discovered dead during the routine check the next day.
WCEP is reviewing the circumstances surrounding the freak storm to determine if we need any changes in our procedures and protocols for the protection of the wintering birds in future years to minimize the chance of any future catastrophic loss.
We are all devastated over the loss of the 17 juvenile cranes. It was a tragic and unfortunate event. While this is a setback for the whooping crane reintroduction project, WCEP has faced challenges in the past and we plan to move forward with our effort to return this highly imperiled species to its historic range in eastern North America.
Breeding season is just now starting up in the captive centers and we are looking forward to the production, training, migration and release of another group of whooping cranes in 2007. We will move forward and rebuild the flock with your support.