Ample rainfall since autumn kept all but one of the 264 birds alive and fully fed in preparation for their seasonal 2,400-mile trek northward to Canada this spring.

After being brought back from near total extinction over the past 40 years, a record 23 of the birds, nearly 10 percent of the South Texas flock, died of starvation last year due to dwindling river flows that wiped out much of the crane’s main diet of blue crab.

There are only about 400 whooping cranes left in North America and the 263-bird flock that nests at the Aransas National Wildlife Refuge is the only one that migrates without human assistance.

The Texas-based Aransas Project has just filed a federal lawsuit in federal court in Corpus Christi, alleging that last year’s 23 crane deaths were due to too much water being diverted from the river that feeds the bird’s habitat.

The group says such diversion for human and agricultural use was a violation of the Endangered Species Act.

“To have a species that was once on the brink of extinction, to bring it back only to turn around and kill it, because we can now manage water use effectively in Texas, I think is a tragedy of global proportions,” said Aransas Project attorney Jim Blackburn.

The Texas Commission on Environmental Quality declined to comment on specifics of the lawsuit. But agency spokesman Terry Clawson told the Associated Press that it's far from certain how low freshwater inflows caused by drought affected the cranes.

Photo: Aransas National Wildlife Refuge