Recovering Endangered Cranes
History
The endangered Mississippi sandhill crane is found only in a small non-migratory population in Mississippi. Historically, they could be found in flocks of thousands in the natural open plains of Mississippi, Louisiana and Alabama. However, the population started decreasing as cities grew and took over their natural habitat, and natural predators moved closer to their nesting locations.
The USFWS started the Mississippi Sandhill Crane National Wildlife Refuge in 1975 under authority of the Endangered Species Act to protect the critically endangered Mississippi sandhill cranes and their unique, wet pine savanna habitat. At that time, the crane population had been reduced to about 35 birds. Part of this recovery program was to create a partnership with zoos to hold individual birds in captivity, breed them, assist in chick rearing and eventually release offspring back to the refuge. The Freeport-McMoRan Audubon Species Survival Center, a facility of Audubon Nature Institute, became involved in this captive breeding project in 1995, and is now one of only two facilities that house, breed and release these birds to the wild.
The wild population, as of 2016, is approximately 130 animals. 65% of those wild birds were hatched and raised at the Survival Center.
Breeding and Release Program
The Survival Center has dedicated approximately eight acres to house, breed and raise Mississippi sandhill cranes, assisting in preventing the extinction of this rare North American crane subspecies.
At any given time the Survival Center houses approximately 40 birds, plus offspring. The birds are paired based on genetics and behavioral compatibility. While many of the birds will naturally reproduce, it often occurs that two birds that match genetically do not get along behaviorally; in these cases Audubon staff has the ability to artificially inseminate the female birds with sperm from a more genetically valuable male.
Crane chicks designated for release are raised two different ways. The preference is for a pair of adult cranes to raise their own offspring or foster chick. The second option is for the animal keeper staff to “costume-rear” the chicks. By dressing up as cranes and limiting human interactions, chicks raised by the keepers are less likely to imprint on humans and more likely to exhibit normal bird behaviors when grown.
A chick may be foster raised or costume-reared for several reasons, including chicks that are produced from eggs collected at the refuge. It is very common for a crane to lay two eggs, unfortunately it is also common for one or both of the chicks to die within the first year in the wild. USFWS biologists at the refuge will occasionally collect one of the two eggs and send it to the Survival Center to hatch and raise. This strategy gives both chicks a better chance at surviving their first year. If the timing works out during the nesting season, the keepers may be able to give the hatched chick to a pair of captive sandhill cranes to adopt and raise, thus foster rearing the chick, otherwise, the keepers costume-rear the chick.
Since the beginning of the program the Survival Center has produced over 200 chicks, with most of those being released back to the wild. The goal of the recovery program is to create a self-sustaining population of Mississippi sandhill cranes at the Mississippi Sandhill Crane National Wildlife Refuge, but while there have been many successes, there are still several challenges to overcome.
The wild population, as of 2016, is approximately 130 animals. 65% of those wild birds were hatched and raised at the Survival Center. The birds are breeding and hatching chicks in the wild, but there is still high mortality among chicks in the first year. To help increase the number of surviving offspring in the wild Survival Center staff uses predator aversion training where keepers will use fake predators, such as a stuffed raccoon, to demonstrate correct protective behaviors to the soon to be released crane chicks.
Mississippi Sandhill Crane Facts
- Status: Critically endangered
- Weight: 3-6kg
- Size: 3-4 feet tall; wingspan of over 7 feet wide
- Color: Adults are gray overall with a red crown and white cheek patch
- Range: Mississippi, USA
- Population: ~130
- Chicks: 1-2 chicks once a year
- Habitat: Wet pine savanna
- Diet: Ominvorous
- Life expectancy: (wild) 20-25yrs, (captivity) 30-40yrs
- Facts: The sandhill crane has a multitude of vocalizations, the most known being a loud, rolling, trumpeting sound that reinforces mate bonds and designates territory. Courting cranes will also dance for each other and together to strengthen their bond.
