By Rex Graham
Thousands of birders are now scanning wetlands across the North American Great Plains, occasionally spotting the continent’s tallest, rarest, and most beautiful bird species. About 300 Whooping Cranes, migrating in small family groups, are making a series of short hops, wetland to wetland, 2,400 miles from subarctic Canada to the Texas Gulf Coast. On their migration paths, bird festivals in the Texas Rio Grande Valley and New Mexico celebrate their arrival in November.
Spirits soar at the site of any endangered Whooping Crane. The only self-sustaining wild population, half of all living Whooping Cranes, nests in the Wood Buffalo National Park, a primeval complex of northern Canadian streams, lakes, wetlands, bogs, and one of the world’s largest river deltas.
In the fall, when young cranes are strong enough, family groups fly to staging areas in Saskatchewan. There they fattened up for weeks before heading south. The final destination of the long-necked white birds with black wing tips and legs is Aransas National Wildlife Refuge (NWR). Aransas is part of a rugged chain of barrier islands that form bays and estuaries along the Gulf Coast about 150 miles southwest of Houston, Texas.
‘Very special’ Whooping Crane moment
“When the first ones arrived and two Aransas biologists ran up to us and said, ‘They’re here! They’re here!’” said Diane Johnson, owner of the Crane House, a lodging business across St. Charles Bay from the Aransas NWR. “It was like two gleeful little boys who got train sets for Christmas.”
This prized gift, a symbol of North American conservation, is the result of international cooperation, targeted research, philanthropy and the efforts of dozens of public and private groups and millions of individuals. Lawyers and judges, relying on the U.S. Endangered Species Act, have played a key role in many states, especially in Texas.
British wildlife photographer Alan Murphy recently watched two adult Whooping Cranes and a juvenile hunt Blue Crabs in St. Charles Bay near Aransas. Murphy’s guide deftly positioned their boat between the morning sun and the birds. They waited patiently. One of the adult cranes, intent on breakfast, waded slowly closer.
“The crane found a Blue Crab, ate only the legs, and dropped the rest back in the water,” Murphy said in an email. “I knew I had to get that moment. When he was right in front of me, he pulled up another large crab, and I fired off a few frames. It doesn’t always come together like that, but when it does, it’s a very special moment.”
Researchers reported in six studies published from 1946 to 2005 that Blue Crabs are an important food source for Whooping Cranes wintering at Aransas: during the 1983-84, 1984-85 winters Blue Crabs constituted 43 percent and 40 percent, respectively, of the volume of winter food consumed; during the winters of 1992-93 and 1993-94 the birds’ daily energy intake from Blue Crabs averaged 90 percent.
Migrating or wintering Whooping Cranes that rely on kernels of grain gleaned from agricultural fields may have inadequate nutrition because they digest grains poorly — much less efficiently than Sandhill Cranes.
Back from brink
Whooping Cranes have come back from a low of 21 wild birds in 1941 to about 600 total birds today. There are so many cranes now that estimates have replaced labor-intensive counting of each Whooping Crane:
• About 300 are in the Aransas-Wood Buffalo flock.
• About 140 are housed at two captive-breeding centers: the International Crane Foundation campus in Baraboo, Wisconsin, and the U.S. Geological Survey’s Patuxent Wildlife Research Center in Laurel, Maryland.
• About 115 make up the eastern migratory population, and most of those birds spend the summer in or near Necedah NWR in Wisconsin, and winter mostly in the area of Chassahowitzka NW in Florida.
• About 25 non-migratory birds are left in the White Lake Wetlands Conservation Area in Louisiana.
• After heavy predation, about 20 non-migrant birds at left at Kissimmee, Florida.
• A handful of birds are on display at the Calgary and San Antonio Zoos.
More cranes at more marshes
The rising number of birds in the Canadian flock is creating the most excitement. The growing flock has created a welcome new challenge at the Texas wintering grounds. Pairs of cranes stake out feeding territories at Aransas and chase away would-be squatters. As a result, 11 percent of the migrants spent last winter in “non-traditional” areas outside of Aransas, such as the Granger Lake and Holiday Beach areas, as well as the Guadalupe River Delta and other marshes.
As the Wood Buffalo flock grows, more suitable wintering sites like the Granger Lake area may be occupied by more birds. Some might even stay at the Nature Conservancy’s Clive Runnels Mad Island Marsh Preserve. But such pristine refuges are relatively scarce.
Millions spent in frustration
“At some point, they will come up against a brick wall of suitable wintering habitat,” said Kirk Winemiller, an ecology professor at Texas A&M University who has studied the foraging needs of Whooping Cranes.
The actual size of suitable wintering habitat relies on ample freshwater inflows to Gulf Coast bays and estuaries. Those inflows will be determined in courtrooms where the Texas Water War is being waged between conservationists and the Texas government.
Charisma, captive breeding, controversy
The most charismatic Whooping Cranes are the first-time migrants taught to fly in Baraboo or Laurel that migrate in formation from Wisconsin behind Operation Migration’s ultralight planes. The pilots dress in white crane costumes to hide their shape so the cranes don’t imprint on a human form.
Away from the roar of ultralights, some question the continuation of a recovery effort that has failed to yet achieve the goal of establishing a self-sustaining population of Whooping Cranes.
At the center of the recovery effort is a captive breeding program in which female Whooping Cranes are artificially inseminated. Their eggs are brooded by more maternal species, and hatch in incubators. Chicks are fed with crane-simulating hand puppets manipulated by costumed humans. Chicks learn to fly by imitating the flapping arms of their costumed keepers.
Some birds will never be released because the genes they carry are considered too valuable to risk losing.
Spending millions in frustration
When released, captive-bred Whooping Cranes have formed pairs, mated and built nests, but some abandon fertile eggs after they’ve been laid. Sadly, the 12-year captive-breeding recovery effort, the most expensive ever for any endangered bird species, has yielded a total of six chicks, including only one in 2013, that fledged in the wild. Unfortunately, many of those chicks have succumbed to predators, disease or genetic abnormalities.
A September 2013 report by the U.S. Fish and Wildlife Service delicately stated the painfully obvious: the reproduction rate of all the captive-bred Whooping Cranes released into the wild “has been too low for the flock to be considered self-sustaining.”
“It’s been frustrating. . . In spades,” Anne Lacy, coordinator of research at the International Crane Foundation, said in a telephone interview. “Part of the problem is our impatience as humans; we would like to see immediate results, but this is a long-lived, low-productivity species, and it may take a long time for successful breeding.”
Little-known ‘gizzard factor’ hurts Wisconsin whooper flock
Another limiting factor of the eastern flock of captive-reared cranes may be their gizzards and the food they eat.
Whooping Cranes are omnivores that prefer to be carnivores. Their cousins, Sandhill Cranes, flourish amid agricultural fields, while Whooping Cranes are specialists of the shallow waters of marshes. On their wintering grounds, Whooping Cranes preferentially hunt easy-to-digest, protein-rich Blue Crabs, shrimp and other invertebrates found in bays and estuaries. Research is critically needed to understand what Whooping Cranes eat at Wood Buffalo National Park.
When Whooping Cranes don’t have marine invertebrates available, they eat corn and other grains. However, they digest grains much less efficiently than other species of cranes, according to Felipe Chavez-Ramirez, one of the world’s leading experts on Whooping Cranes and director of conservation programs at the Gulf Coast Bird Observatory in Lake Jackson, Texas.
Unfortunately, many of the captive-bred Whooping Cranes in the eastern migratory population decided to spend the 2012-2013 winter in the Corn Belt state of Indiana.
Poor Whooping Crane diet amid (seeming) plenty
Sandhill Cranes flourish on carbohydrate-rich agricultural grains. They swallow gizzard stones, which crack and grind the husks of seeds and grains. Such food is increasingly important in the diet of the eastern migratory population of Whooping Cranes, but that’s a problem because those cranes don’t swallow gizzard stones.
“Sandhill Cranes have stones in their gizzards to efficiently grind up and digest grains. In fact, you need a microscope to find pieces of corn in their feces,” Chavez-Ramirez said.
“A Whooping Crane that eats just vegetable material may have to eat twice as much as a Sandhill Crane, and still might not make it on that diet,” Chavez-Ramirez said.
Lacy said International Crane Foundation researchers are investigating what Whooping Cranes eat on their wintering grounds to better understand their optimal and adequate dietary needs.
Magnifique: Crabe bleu a la clam
Chavez-Ramirez’s research has documented that the top food item for Whooping Cranes at Aransas is protein-rich Blue Crabs. The Aransas cranes also eat fish, razor clams, acorns, crayfish, snails, insects, berries and grass. Chavez-Ramirez said the hard shells of ingested clams and snails may serve the same purpose as gizzard stones, helping to break up Blue Crabs and other food items into smaller, more digestible pieces.
Chavez-Ramirez said Whooping Cranes with a protein-rich diet of Blue Crabs, clams and other invertebrates are in prime condition to migrate, mate and perform other behaviors at a high level. However, cranes that eat grains gleaned from agricultural fields may slip into poorer condition.
St. Charles Bay and the adjoining bays and estuaries near Aransas NWR are home not just to Blue Crabs, but also to oysters, shrimp, and a wide range of other invertebrates that birds, fish and the Texas fishing industry rely on.
Captive-teaching gap: parenting
Captive breeding is still an important option for endangered bird species. It saved the California Condor, Mauritius Kestrel, Guam Rail and Grey Partridge. Trumpeter Swans rebounded with captive breeding after being nearly extirpated by hunting and lead poisoning. Despite avid public and governmental support for captive breeding of many endangered species, such as lions, experts say release of captive-origin lions “have no role in species restoration.”
The swans can live 33 years, begin breeding by age 4 to 6, and females lay clutches of up to 12 eggs.
Whooping Cranes reach sexual maturity after about three years, but longevity is up to 24 years in the wild. Mated pairs at Wood Buffalo National Park fledged 0.53 chicks per nest in the summer of 2012, an increase from 0.48 chicks per nest in earlier years. (The combined fledging rate for all the captive-bred cranes released in Wisconsin, Florida and Louisiana is essentially zero.)
Lacy and others involved in the Whooping Crane recovery effort fear that human-reared Whooping Cranes simply may not know how to be good parents. Or they may need more time to learn to be better parents. But how?
Scientists reported in the Aug. 30, 2013, issue of Science that 1-year-old Whooping Cranes drifted off-course less while migrating if they were being escorted by older Whooping Cranes.
“Learning of migration routes by Whooping Cranes takes place over many years, and social transmission of knowledge by experienced, older birds yields progressive improvements in migratory performance of younger birds,” said the Science co-authors, led by migration expert and University of Maryland biologist Thomas Mueller.
Learning parenting skills is probably much more difficult for captive-bred Whooping Cranes. “We really don’t know why they may not be able to be ‘good parents,'” Lacy said. “Many of the breeding pairs [released in Wisconsin] are of mixed age and experience. The population is really too small and too young to know right now.”
Update failed program?
“We are fortunate to have supporters saying that we should never stop trying,” Lacy said. “But others are asking, ‘Given the amount of money that’s been spent, and the number of people-hours involved, how do you know when to say when?’”
Other questions relating to the captive-breeding program include these:
• Would a truly independent review, run by outsiders applying universally accepted ethical standards of animal research, conclude that after 12 years of failure, that it is appropriate to continue the eastern flock captive-breeding program with its current goal of establishing a wild flock?
• Would the bulk of the money spent to prop up the failed, non-sustaining eastern flock be more wisely spent to boost the self-sustaining Aransas-Wood Buffalo flock?
• What criteria should be used to decide if and when to change the goal of current captive-breeding programs to these: preserve genetically important individuals, and provide birds to educational programs at zoos?
Sexy vs. common sense
“Reintroducing an endangered species is a very sexy project,” Winemiller said. “I’ve always been a proponent of protecting habitat, and doing what’s needed to support birds that breed in the wild rather than captive-breeding programs.”
Power lines, trigger-happy hunters
Whooping Cranes perish while migrating, even in good years at Aransas. The most deadly migration hazard is a gauntlet of power lines. Collisions are lethal. So too, are hunters. At least seven Whooping Cranes were shot in 2011 in the U.S. Penalties for killing a Whooping Crane have ranged from $1 in Indiana and $10,000 in Texas to an $85,000 fine in 2013 in South Dakota that also included two years’ probation, confiscation of the hunter’s rifle and removal of the man’s hunting and trapping rights in the U.S. for two years, according to WildlifeExtra.com.
On Jan. 12, 2013, a hunter said he accidentally killed a juvenile Whooping Crane in a costal marsh off San Jose Island near Aransas NWR, when he mistook it for a Sandhill Crane. (The hunter, a member of the St. Charles Bay Hunting Club, also said didn’t know the area was closed even to Sandhill Crane hunting as a safety precaution for wintering Whooping Cranes.) The hunter was fined $5,000 and required to pay $10,000 to Friends of Aransas and Matagorda Island National Wildlife Refuges.
Unfortunately, Sandhill Cranes can still be hunted in most states on Whooping Crane migration routes. Nebraska ended hunting of Sandhill Cranes in order to greatly reduce the possibility of Whooping Cranes being shot, especially along the critically important Platte River Valley.
There are currently plenty of bird species for hunters to legally kill. No crane species should ever be one of them.
Federal protection vs. Texas drought
The near-extinction of Whooping Cranes and other bird species was a guiding force behind passage of the Endangered Species Act by the U.S. Congress and signed into law by President Richard Nixon in 1973. That was three years after the first Earth Day. “A revolution in values,” Nixon wrote in a letter to Congress, “replaces cavalier assumptions that we can play God with our surroundings and survive.”
The Endangered Species Act gave The Aransas Project, an alliance of citizens, organizations, businesses, and municipalities, the legal standing to win court rulings that set aside “environmental flows” of freshwater to bays and estuaries along the Texas Gulf Coast. A lawsuit filed by the Aransas Project against the Texas Commission of Environmental Quality (TCEQ) argued that too little freshwater in 2008-2009 led to the deaths of as many as 23 Whooping Cranes.
“Growing municipalities need more water, but many people make their living from healthy ecosystems, which are made possible with flows of freshwater to the Gulf,” Winemiller said. “The side that usually loses is the natural environment.”
Indeed, on July 5, 2011, Texas Governor Rick Perry renewed his drought-emergency proclamation, citing record high temperatures and declining reservoir levels. Perry’s proclamation states that “all [state] rules and regulations that may inhibit or prevent prompt response to this threat are suspended for the duration of the state of disaster.”
Citing Perry’s decision, the Lower Colorado River Authority (LCRA) on Sept. 26, 2013, asked TCEQ for an “emergency suspension of bay and estuary inflow requirements.” Such a suspension of freshwater could lead to devastating increases in the salinity of bays and estuaries currently receiving that water.
LCRA provides water for irrigated agriculture in Texas. In a 2011 trial of its lawsuit, The Aransas Project described the state’s approach to water allocation “archaic,” drawn up when “water was considered wasted if it made it to the bay.”
Since Sept. 26 Texas has benefitted from rain. On Oct. 16, LCRA asked TCEQ to hold off on its emergency-suspension request until at least Nov. 27, 2013, due to “considerable rainfall.” Rebecca Motal, general manager of LCRA, said in an Oct. 16, 2013, letter to TCEQ that the rains helped raise the water levels of two large reservoirs on the Lower Colorado River Basin in Texas.
The continuation of needed freshwater to the Texas Gulf Coast ecosystems could be short-lived. In her letter, Motal said LCRA may ask to cut off freshwater to the Gulf in 2014.
Bay salinity focus of Texas Water War
When the salinity of the brackish water of St. Charles Bay rises because too little freshwater flows in, invertebrates begin to disappear. Whooping Cranes find fewer Blue Crabs and fish.
Cranes turn to wolfberries, which ripen in November and December, just in time for the cranes’ arrival, but berries are no substitute for crabs. Hungry Whooping Cranes eat more snails and insects and spend more time hunting harder-to-find Blue Crabs.
Whooping Cranes will even resort to eating grain. “They come to our deer feeders and eat corn,” said Johnson, the Crane House owner. (At the request of the U.S. Fish and Wildlife Service, Johnson puts out only mold-free corn in her deer feeders in case cranes eat it.)
A 2013 paper in The Wilson Journal of Ornithology reported that between 1998 and 2006 the deaths of Whooping Cranes at Aransas rose when the supply of Blue Crabs fell. During those years, the reproduction rate of the Whooping Cranes in Canada was just enough to replace the adults that didn’t return from Aransas, according to a report by the International Crane Foundation.
“Mortality is high during years of low crab abundance and declines towards zero during years of high abundance,” said the authors of the Wilson Journal paper, led by Bruce Pugesek, an adjunct professor of ecology at Montana State University.