Chasing the Ghost Birds: Saving Swans and Cranes from Extinction, a Book by David Sakrison

Excerpt from Chapter 15:
"It Works!"

In 1995, biologist/rancher Kent Clegg led a flock of captive-raised sandhill cranes on a migration from Idaho to New Mexico. It was the first time cranes had ever followed an ultralight on migration and it paved the way for the introduction of a new migratory flock of whooping cranes in the Eastern United States. That project began in 2001 and continues today.

Out in Idaho, Kent Clegg's class of sandhill cranes hatched in early May 1995 and was introduced to his ultralight aircraft about three weeks later. Every few days, Clegg flew the airplane in a low pass over the pen, then landed and briefly left it idling near the birds' pen. Over the summer, the birds learned to follow an ATV, then the taxiing ultralight, and finally the flying ultralight, encouraged by Clegg's brood calls.

Shortly before they left on migration, the cranes were fitted with bright yellow leg bands with black numbers for easy identification, and with solar-powered transmitters (with battery backup) for radio tracking.

On the morning of October 16, Clegg led the 11 sandhill cranes south away from the ranch on the world's first ultralight-led crane migration. Two birds that were injured earlier in the summer during flight training were left behind. Clegg was worried that they might not be able to keep up with his Dragonfly ultralight.

A second ultralight joined the flight, a Challenger flown by Errol Spaulding of Ririe, Idaho. Spaulding is a heavy-duty mechanic who loves to fly and has flown a wide range of ultralight and experimental aircraft. With its much faster cruise speed (100 mph, 160 km/h, max.), Spaulding's Challenger could scout ahead for landing sites and wind conditions, and fly "high cover" to protect the cranes from eagle attacks, which typically came from above and behind the flock.

A four-person ground crew rode in three vehicles. A pickup truck and a lightweight four-wheel-drive truck were the chase vehicles. A heavier pickup towed the ultralight's trailer; it carried the portable pen that was used along the route, and would carry the Dragonfly back to Idaho at the end of the trip.

The 11 birds settled in quickly. Flying in formation and riding on the ultralight's wingtip vortices required more wing flapping than a simple glide, but was much more efficient for the birds than flapping along on their own.

On most days, the morning flight would begin about 9 a.m. and last for an hour or two. When the birds or the pilots decided it was time to land, the portable pen was set up and the birds were rested during the day. If the winds died down enough in late afternoon, the team would make a second flight just before sunset, then pen the birds for the night, to protect them from predators. In a single day, the flights covered anywhere from 25 to 120 miles (43 to 217 km). The birds averaged about 30 mph (50 km/h) in flight with sprints up to 42 mph (70 km/h).

During the afternoon flight on Day One, about 75 miles south of the Clegg Ranch, one of the cranes disappeared. It showed up back at the Clegg ranch three days later.

On the second day of the migration, two of the birds quickly showed signs of tiring during morning flight, and were unable to keep up with the rest of the flock. When one bird dropped out of formation to land, the other birds tried to join it. To keep the flock in the air, the two stragglers were carried in the trailer for much of the trip. One of the stragglers was later diagnosed with coccidiosis, a common ailment among cranes that can cause respiratory problems.

The second morning's flight also saw the first of five eagle attacks during the migration. As the flock crossed a high pass in the Bear River Mountain Range, two of the cranes lagged below and behind. In a diving attack from behind, a pair of golden eagles struck the two cranes. One crane was hit and driven to the ground 1,500 feet (460 m) below. The other crane dodged the initial strike and took off with the eagle in hot pursuit. The two were last seen disappearing over a ridge. The ground crew recovered the remains of the first crane; the second was never found.

The rest of the flock scattered. The ultralights landed and the birds followed them to the ground, panting and wild-eyed. It took several hours in the portable pen to calm them down. Still, the team made two more flights that day, covering a total of 83 miles (134 km).

Eagles typically attack in high-speed dives from above and behind. The momentum of the attack can drive their razor-sharp talons deep into the victim's lungs or other organs and carry both predator and prey to the ground. During the 1995 migration experiment, the cranes often gave the first warning of an attack when they crowded in under the wings of the Dragonfly.

As the migration went on, the pilots learned to head off attacking eagles. In the Challenger, Spaulding carried a shotgun loaded with "cracker shells." The shells fired a small charge that exploded about 50 yards (45 m) out of the barrel. That was usually enough to discourage the eagles. There were four more attacks, and eagles were seen on two other occasions, but none of the other cranes was injured by eagles during the 1995 migration. . .

Excerpt from Chapter 12:
"Shall We Dance?"

This chapter describes early efforts to breed whooping cranes in captivity.

Douglas Alexander Spaulding discovered the phenomenon that we now know as "imprinting." Spaulding discovered that when goose hatchlings were denied any contact with other geese, they quickly and easily accepted other creatures, including humans, as their rightful parents.

But imprinting goes beyond answering the question, "Who's my mama?" A very young gosling, imprinted on a chicken, will think it is a chicken-but not exactly. It will think its chicken foster parent is a goose, but not exactly. It will bond with the chicken's flock and it will learn some distinctly chicken-like behaviors from its surrogate parent. Yet it will also retain its goose instincts. When it comes time to pair off and mate, our chicken-imprinted gosling will seek its mate among the chickens, showing no interest in other geese. Its courting behaviors remain distinctly goose-like, but the chicken-imprinted goose will aim its courtship in the wrong direction -- toward chickens -- and will not respond to courtship displays from other geese, even though those displays are identical to its own courtship behavior.

When whooping crane eggs were placed in wild sandhill crane nests in the 1970s, the experiment failed to create a new, productive wild population of whoopers. Imprinting was a key factor in that failure. Each of the young whoopers imprinted on its sandhill foster parents. When the foster-raised whoopers reached sexual maturity, a few of the males tried to pair off with young sandhill cranes, showing no interest in the other whoopers in the flock. As for the young sandhills, they knew who they were. And it was all well and good to share the playpen with those funny-looking foster-cousins, but pairing off and mating with them was, well--dear me!--out of the question.

[The whooping crane named] Tex was a classic case of misdirected imprinting She had spent her crucial "formative" weeks in Fred Stark's living room, interacting with humans. She had imprinted on humans and had no real interest in other cranes.
From the San Antonio Zoo, Tex moved to the U.S.G.S. Patuxent Wildlife Research Center in Maryland. Crane researchers hoped that there, among Patuxent's captive flock of cranes, Tex might sort it all out and pair off with another crane.

At Patuxent, Tex reached sexual maturity and began making typical whooping crane mating displays--to her human keepers. For ten years, Patuxent biologists tried to get Tex to mate with another whooper. She would have none of it. She mostly ignored the feathered suitors they paired her with, but she would begin a courtship display whenever a human came near her pen.

The biologists at Patuxent talked it over with Dr. George Archibald at the International Crane Foundation, in Baraboo, Wisconsin, and he offered to take Tex on as a personal project. He hoped that under more controlled conditions at ICF, Tex might be persuaded to pair off with another whooper. If that failed, the staff at Baraboo was prepared to pair her off with George, artificially inseminate her, and hope for an egg.

Breeding cranes in captivity has always been a challenge. Zoos have bred cranes but not very often. At Patuxent, Dr. George Gee developed successful techniques for artificial insemination of cranes in the early 1970s. George Archibald studied the crane management at Patuxent as a graduate student at Cornell University. He and fellow student Ron Sauey would later found the ICF and make captive breeding one of ICF's most important goals.

For ICF, successful captive breeding and hatching sometimes required simulating the climate of a crane's wild nesting range at Baraboo. For Brolgas, a crane species nesting in northern Australia during the monsoon season, that meant watering the birds twice a day with "rain" from garden hoses. For hooded and Siberian cranes that nest in the far north of Siberia, it meant artificial lights to simulate the long arctic days.

Crane eggs do best if they spend at least half their incubation period under live birds. Sandhill cranes proved to be excellent foster parents for that purpose. About halfway through the 30-day incubation period, the eggs are moved to the artificial incubator, where ICF staff simulate as closely as possible the care and conditions in the nest, from turning the eggs every few hours to cooling the eggs twice a day -- to mimic the handoff when one parent leaves the nest to feed and the other parent settles onto the nest.

Through careful study and observation, creativity, and much trial and error, ICF successfully bred 13 of the world's 15 species of crane during its first ten years of operation (1973-83).

Tex arrived in Baraboo from Patuxent in the spring of 1976, the first whooping crane to reside at ICF's headquarters and research facility. Two weeks later, she was joined at Baraboo by Tony, a whooping crane on loan from Audubon Park Zoo in New Orleans. At the time, Tony and Tex were two of only three surviving whoopers who were produced from captive parents, and two of only 84 whooping cranes in existence.

The mood at ICF that spring was definitely hopeful. Although Tony had so far been a bachelor, he appeared to be in excellent health. He and Tex were placed in adjacent pens that allowed them to get acquainted without any risk of fights or feather pulling. (Though not as fierce as Siberian cranes, whoopers are jealously territorial and can be extremely aggressive toward each other.) ICF staff reported that both birds were responding well to their new surroundings and that they were occasionally dancing and calling together. These were not full blown mating behaviors -- being more on the order of "flirting" -- and there was little chance that Tex would actually accept Tony as her mate, given her history. But the dancing and unison calling were positive signs. They should have triggered hormonal changes in both the birds that are necessary for production of eggs and semen.

But it soon became obvious that Tex wasn't really interested in Tony. She was far more interested in her human keepers. In the early summer of 1976, ICF Director and "Head of Propagation" George Archibald moved into Tex's pen. Behind a chicken wire divider, George set up his office in the enclosure, with a desk and an old manual typewriter. "During those first eventful weeks together," George wrote in the ICF Bugle, "I learned to wake to an unusual alarm clock -- Tex blasting 110-decibel calls beside my bed at dawn's first light."

When Tex wanted to dance, George danced, waving his arms, jumping up and down, and throwing sticks in the air. George spent most of the spring and summer of 1976 in the pen with Tex, and the two became solidly bonded.

[All cranes "dance" as part of their courtship behavior, running, leaping high in the air, flapping their wings, and calling to each other.]

In the spring of 1977, George returned to Tex's pen for several weeks, spending every day with her, from dawn until dark, seven days a week. They danced and when the time was right, Tex was artificially inseminated with semen from one of Patuxent's whoopers. At age ten, Tex laid her first egg. It was infertile.

The next spring, 1978, George moved in with Tex again. Again they danced and again she was artificially inseminated. This time the egg was fertile, but the embryo died just before it was due to hatch. In 1979, she laid a third egg, but it was soft-shelled and it cracked. Hopes of continuing Tex's genetic line were crumbling. Her parents, Rosie and Crip, were both dead and she had no living siblings.

If Tex produced no offspring, an important genetic line and a source of genetic diversity would be lost to the world's remaining whoopers.

Mike Putnam, ICF's Curator of Birds picked up the story. In the spring of 1980, George was working in China. Yoshimitsu Shigata, a Japanese ornithologist, had asked to fill in for him, bonding and dancing with Tex. But Tex didn't fancy Shigata and she laid no eggs that spring.

"She was a peculiar bird," Putnam said. "It turned out that she hated women and oriental or red-haired men. If you were sort of medium height to tall and had darkish hair, that was okay; that was what she liked in men." After Tex rejected her Japanese suitor, another ornithologist tried to take up with her. "He was about my height and had a beard like me," Putnam explained, "but he had red hair and Tex didn't want anything to do with him. George and I looked enough alike in height and build and hair color that she liked us both. . ."