Strange Year for Whoopers
Endangered cranes found winter homes outside Aransas refuge and left Texas earlier than usual.
By Steve Lightfoot
It’s been an unusual year for whooping cranes in Texas, and the endangered species’ spring migration is the latest example. Researchers reported that several whooping crane families initiated their spring migration nearly a month earlier than usual, with some birds reaching South Dakota by the end of March.
After a winter distribution that surprised biologists and kept birders enchanted with unprecedented viewing opportunities for one of North America’s most ancient bird species, the unusually early start of the migration to nesting grounds in Canada does not surprise Texas Parks and Wildlife Department biologist Lee Ann Linam.
“This winter seemed to produce a ‘perfect storm’ of mild winter weather, reduced food sources on the Texas coast and crowding in an expanding whooping crane population, which led whooping cranes to explore new wintering areas,” Linam said. “Those same conditions have likely provided the impetus for an early start of their 1,500-mile spring migration.”
Texas provides wintering habitat for the only self-sustaining population of whooping cranes in the world. Traditionally, whooping cranes spend December through March in coastal wetlands on and near Aransas National Wildlife Refuge, between Rockport and Port Lavaca. In recent years, whoopers have slowly expanded their winter range — usually using coastal marshlands adjacent to already occupied areas.
However, in 2011-12, whoopers made significant expansions southward and westward of Aransas National Wildlife Refuge, and one whooping crane apparently spent the winter with sandhill cranes in upland habitats near El Campo. Even more significantly, nine whooping cranes, including six adults and three chicks, spent most of the winter near Granger Lake in Central Texas, and one family group of whooping cranes traveled only as far south as Kansas before heading back north to spend most of the winter in Nebraska.
The unprecedented shifts may be indicators of both bad news and good news for the Texas flock, which is thought to now number about 300 birds, according to Linam.
“We are concerned about the health of our coastal estuaries and long-term declines in blue crabs, one of the traditional primary food sources for this population of whooping cranes,” she said. “At the same time, these cranes seem to be showing adaptability as the increasing population may be causing crowding in traditional habitats and drought may be producing less than ideal habitat conditions. I think it’s a good sign that whooping cranes are exploring and thriving in new wintering areas.”
Whooping cranes are the tallest birds in North America, standing nearly 5 feet tall. They are solid white in color except for black wing-tips that are visible only in flight. They fly with necks and legs outstretched. During migration, they often pause overnight to use wetlands for roosting and agricultural fields for feeding, but seldom remain more than one night. They nearly always migrate in small groups of fewer than four to five birds, but they may be seen roosting and feeding with large flocks of the smaller and darker sandhill cranes.