A non-profit organization for environmental preservation.
Nature's Guardian is dedicated to helping preserve endangered species, like the Whooping Crane. Once very close to extinction, the whooping crane is making a comeback,thanks to conservation efforts over the last few decades. In 1937, onlytwo small breeding populations of the whooping crane remained; anonmigratory population in southwestern Louisiana, and a migratorypopulation which nested in Canada and wintered on the Texas Coast.Today, there are nearly 300 whooping cranes in the wild and incaptivity.
Before settlers moved west, whooping cranes nested from Illinois tosouthern Canada, sharing their nesting grounds with the grizzly bear,bison, and gray wolf. Whooping cranes migrated to areas extending fromthe Carolinas to Mexico to spend the winter.
But with the settlement of the West, much of the crane's prairie nestinggrounds were converted to pasture and agricultural lands. Whoopingcranes therefore disappeared from the Great Plains, finding safe refugefar north in Canada at the Wood Buffalo National Park. This was notknown until 1954, when a pilot spotted a pair of whooping cranes at thepark. And in 1941, records show only 16 birds had migrated to winteringgrounds on the Aransas National Wildlife Refuge on the Gulf Coast ofTexas.
The tallest bird in North America, the whooping crane stands 5 feet tallwith a long, sinuous neck and long legs. Its snowy white body feathersare accented by jet-black wingtips and a red and black head with a long,pointed beak. The wings measure about 7 feet across. Whooping cranes flywith slow wingbeats and the necks and legs fully extended.
The whooping crane's call, from which it derives its name, has beendescribed as a shrill, bugle-like trumpeting.
Whooping cranes nest in marshy areas among bulrushes, cattails, andsedges that provide protection from predators as well as food. They eatinsects, minnows, crabs, clams, crayfish, frogs, rodents, small birds,and berries.
Whooping cranes do not reach breeding maturity until they are 4 yearsold, and they establish life-long mates. Their courtship dance, whichbegins in late winter, consists of loud vocalizations, wing flapping,head bowing, strutting, and tremendous leaps into the air by one or bothbirds. This behavior may also occur when birds are defending theirterritory.
Whooping cranes usually nest once each year, unless their first clutchis destroyed they sometimes will lay another. Also, occasionally a pairwill skip a nesting season if conditions are unsuitable or for noapparent reason. Normally two eggs are laid in late April to mid-May,with hatching 1 month later. The parents share incubation and rearingduties, but females take the primary role in feeding and caring for theyoung. Usually only one of the two chicks is raised.
Whooping crane chicks have reddish-cinnamon colored feathers. Slowlyover their first winter, juvenile plumage is replaced, and by thefollowing spring it is mostly white, with full adult plumage beingreached by late in the second summer.
Fall migration begins in September, and whooping cranes normally migratein small flocks of less than 10. They arrive at Aransas NationalWildlife Refuge in Texas between late-October and mid-November, wherethey will spend about 6 months. In April, the birds make the 2,600-miletrip back to Wood Buffalo National Park in Canada.
It has been estimated that between 500 and 1,400 whooping cranesinhabited North America in 1870. While never very numerous, severalfactors contributed to their rapid decline. Many cranes have died fromcollisions from power lines. Substantial numbers were lost to illegalshooting for meat and sport. Some have died of avian tuberculosis, aviancholera, and lead poisoning. Due to their long migration route, whoopingcranes also are vulnerable to natural disasters such as hail storms ordrought. The whooping crane's delayed breeding maturity and small clutchsize make the population as a whole less capable of rebounding fromthese threats.
Various efforts have helped the whooping crane over the years. Passageof the Migratory Bird Treaty Act of 1918 gave protection to whoopingcranes and other birds, thus thwarting illegal shooting. Canada's WoodBuffalo National Park, while established in 1922 to protect the buffalo,was a safe haven for the last nesting population of the whooping craneat that time. In 1937, the Aransas National Wildlife Refuge wasestablished to protect the wintering area of the remaining whoopingcranes. In 1967, the whooping crane was designated as an endangeredspecies (under a law that preceded the Endangered Species Act of 1973),meaning it was considered in danger of extinction throughout all or asignificant portion of its range.
In 1967, the U.S. Fish and Wildlife Service began a whooping cranerecovery program, relying on an extensive captive breeding effort whichhas been met with many challenges due to the whooping crane'ssensitivity to human contact. To date, three facilities are nowcaptively rearing whooping cranes for reintroduction into the wild, andflocks have been reintroduced into the wild at two sites. These effortsbegan because of the risk of losing the entire wild flock of whoopingcranes due to a natural disaster such as disease or hurricane, and tohelp increase whooping crane numbers.
Since whooping cranes normally lay two eggs but only raise one chick, inone experiment, Canadian and American biologists removed the "extra"eggs from nests in the wild and brought them to the Patuxent WildlifeResearch Center in Laurel, Maryland, where they were artificiallyincubated and later used to establish a captive flock. From 1967 throughthe present, many "extra" eggs have been transferred from the wild tothe Patuxent center and other whooping crane captive breedingfacilities.
Artificial insemination also proved successful in increasing the numberof eggs laid by captive cranes. Once a crane laid a clutch of eggs, theeggs were removed to be incubated either artificially or by a sandhillcrane, a closely related species. The whooping crane would then lay asecond clutch of eggs.
An effort to create a wild flock with an alternate migratory route wasinitiated in 1975, using sandhill cranes as "foster parents." Whoopingcrane eggs were placed in the nests of sandhill cranes on their nestinggrounds at the Grays Lake National Wildlife Refuge in Idaho. Thesandhills reared the chicks as their own, teaching them feeding habitatsand ultimately a new 850-mile migratory path to the Bosque Del ApacheNational Wildlife Refuge in New Mexico. Unfortunately, these whoopingcranes became so accustomed to their sandhill parents that they wouldnot mate with other whooping cranes. Today, there are 8 whooping cranesleft in this flock.
In 1989, a second captive flock was established at the InternationalCrane Foundation in Baraboo, Wisconsin, a conservation organizationdedicated to the preservation of cranes worldwide. In addition to birdsfrom the Patuxent center, some of these whooping cranes have been usedfor reintroduction efforts.
In February 1993, a nonmigratory flock of 14 captive-reared whoopingcranes was reintroduced on the Kissimmee Prairie in Florida. Since then,19 more birds have been released at this site. Twenty-five more birdswill be released in the winter of 1994-95, and annual releases of around20 birds are scheduled for the next 8 years. Bobcat predation, which iscommon among sandhill crane populations in the same area, has been thegreatest cause of mortality for this flock.
>From 1992 to the present, 18 whooping cranes have been transferred to afacility in Calgary, Canada, to establish a third captive flock.Presently, biologists are evaluating sites in Canada for thereintroduction of a migratory flock of whooping cranes later thisdecade.
Thanks to these efforts, the whooping crane population has survived andcontinues to increase. The U.S. Fish and Wildlife Service's whoopingcrane recovery program has been so successful that other countries haveadopted similar methods to protect other species of crane that are alsothreatened.