On a winter morning in Texas, as a pair of whooping cranes and their half–year–old juvenile are wading in a tidal marsh on Aransas National Wildlife Refuge, a scene unfolds that is hard not to anthromorphize. One adult plucks a blue crab from the water, holds it in its bill, walks over to the juvenile, cracks the crab and appears to feed the crustacean to the juvenile.


Blue crabs are a mainstay of the whooping crane diet. This winter was a banner one for cranes at Aransas Refuge, but refuge manager Dan Alonso is concerned about their future—in part because, he believes, blue crabs are being overharvested and in part because Gulf of Mexico coastal habitat is disappearing rapidly. So, the refuge is taking new steps to help North America’s tallest flying bird.


The Aransas Refuge population, the only natural flock of endangered whooping cranes, nests at Wood Buffalo National Park in Canada in spring and summer. From early fall to late December, the cranes migrate in small groups to the Texas refuge. In early spring, they rush 2,500 miles back to Canada in 15–16 days. “They’re usually all gone by April 15,” says Alonso. “They don’t want to be taxed.”



Record–Breaking Season

A record–breaking 281 cranes wintered at Aransas Refuge this season. That’s half of this continent’s whooping cranes. Approximately 100 others occur in the human–induced Wisconsin–Florida migration route, and about 167 are in captivity (many at Patuxent Research Refuge, MD).


The Aransas Refuge crane numbers are up from 15 in 1941, but the genetically homogeneous population remains prone to catastrophic disease, and human development is devouring the cranes’ habitat. “That is what has imperiled the species to the degree it is today,” says Alonso. “We’re constantly losing shoreline, either through outright development or bulkheading—putting up a barrier that prevents the water from flowing into the marsh or the estuary. That basically kills the estuary, rendering the habitat unusable” for cranes. Whooping cranes—which are five feet tall, have a seven–foot wingspan and can fly up to 45 mph—thrive on open tidal marsh. They dislike thick cover (or densely wooded areas), Alonso says, “because it doesn’t afford them the opportunity to elude predators”—primarily coyotes and bobcats.


A team led by longtime U.S. Fish and Wildlife Service whooping crane coordinator Tom Stehn is working with various partners to estimate the amount of additional suitable habitat that is needed in Texas to foster species recovery.


Cranes are “voracious eaters” that forage in marsh for razor clams, minnows, lizards, snakes and, especially, blue crabs, Alonso says, but the commercial fishing industry is overharvesting crabs.


Alonso, who came to Aransas Refuge about two years ago, has placed renewed emphasis on enforcing and publicizing regulations that prohibit commercial fishing for blue crabs in refuge waters at all times. “We let the commercial fishermen know that this was a longstanding regulation in place, but that it was going to be enforced more strictly than it had been in the past,” he says.


A consortium of government and nongovernmental entities that includes the refuge is advocating blue crab conservation. The refuge also participates—with nonprofits, sportfishermen and volunteers—in an annual abandoned crab trap pickup. For a nine–day period in February, any trap found in the water is considered abandoned and removed. This is important because abandoned traps continue to catch crabs—which then die, unharvested. In nine years, 27,052 “ghost fishing traps” have been removed. Alonso wants to hold industry accountable for such traps—for the cranes’ sake.


“They’re just so majestic,” he says of the birds that help attract an estimated 45,000 visitors to Aransas Refuge each winter. “They’re large, they’re awe–inspiring—bright white with black wingtips. Being as large as they are, they’re still very graceful … highly charismatic, enjoyed by many. And given their state of low numbers, it makes them that much more appealing and sought after.”