Whooping Crane Population Reaches Record High
The tallest bird in North America has something special to “whoop” about. The Aransas National Wildlife Refuge today announced the highest numbers of endangered whooping cranes are wintering in Texas in approximately the last 100 years.
U.S. Fish and Wildlife Service Whooping Crane Coordinator Tom Stehn completed a census flight on December 10th and tallied 189 whooping cranes. The current population exceeds by one the previous high of 188 whoopers present in the fall of 1999.
The increase in numbers is due to very good nest production last summer. A record 61 nesting pairs fledged 27 chicks on their nesting grounds in Wood Buffalo National Park, Canada, as reported by the Canadian Wildlife Service. The young cranes were old enough to fly by mid-August increasing their ability to escape from predators and their survival. The record population of 189 includes 24 young cranes that have completed their first migration to Texas.
Although the whooping crane population remains endangered, the comeback of the species sets a standard for conservation efforts in North America.
The population in Texas reached a low of only 15 birds in 1941, before efforts were taken to protect the species and its habitat. The population has been growing at 4 percent annually and reached 100 birds in 1987. “We were hoping for 200 whooping cranes in the year 2000, but the population went into a decline for a couple years before rebounding back to 185 cranes last winter,” said Mr. Stehn.
The whooping crane population continues to face many threats, including collisions with power lines in migration, limited genetic variability in the birds themselves, loss of crane migration habitat, and winter habitat threatened with loss of productivity due to reduced fresh water inflows and chemical spills.
The only natural wild population of whooping cranes nest in the Northwest Territories of Canada in summer and migrate 2,400 miles to winter at the Aransas and Matagorda Island National Wildlife Refuges and surrounding areas. Their winter range stretches out over 35 miles of the Texas coast about 45 miles north of Corpus Christi, Texas. Wintering whooping cranes use salt marsh habitat foraging primarily for blue crabs.
Unlike most other bird species, whooping cranes are territorial in both summer and winter and will defend and chase all other whooping cranes out of their estimated 350-acre territories.
Although whooping crane migration starts in mid-September and is usually completed by mid-December, it is still possible that a few additional cranes will turn up to be counted on the weekly census flights conducted by the Service. It takes up to 8 hours of flying to cover the 55,600 acres of marsh over a 35-mile stretch of the Texas coast to find all the cranes. These flights determine the size of the total population, locate crane territories, and any mortalities that may occur.
“Finding every whooping crane every week is quite a challenge. We have thousands of other white birds in the marsh including pelicans and egrets that makes aerial spotting of cranes more difficult. Also, the cranes can move during a census flight and either not be counted or else be counted twice.” said Mr. Stehn.
If a disease outbreak should occur affecting the Texas flock, a contingency plan to reintroduce two additional flocks into the wild is in place. Since 1993, captive bred whooping cranes have been released annually in central Florida. Today, that non-migratory flock numbers approximately 75 birds. During the past two years these cranes demonstrated their maturity by nesting and producing chicks on their own.
A migratory flock was established using an ultra light aircraft to teach the whooping cranes a migration route between Wisconsin and Florida. This migratory flock now numbers 36, with the cranes flying solo after being led on their initial trip across the eastern U.S. behind the ultralight.
On December 8th, sixteen whooping crane juveniles completed their migration from Wisconsin led by ultra light aircraft. The team of pilots and biologists assigned this task make up the Whooping Crane Eastern Partnership. The current total North American population of wild and captive whooping cranes is 426.