When it comes to training whooping cranes to be good mothers, 67-year-old Lloyd Lindvall uses wood.
The Columbia resident makes hand-carved wooden eggs, which are placed in whooping cranes' nests as a substitute for their real eggs. The real eggs are removed and incubated at the Patuxent Wildlife Research Center in Laurel.
The substitution prevents the endangered species from breaking and eating the eggs, which they often do, experts say.
"It sounds ridiculous. It is ridiculous, but birds are sometimes odd," Lindvall said.
The trick seems to be working. So far, three chicks have hatched and are alive because of the switch.
Lindvall is a member of the Howard County Woodworkers' Guild and a retired special agent for the U.S. Fish and Wildlife Service, which works with the research center.
In the spring, Sandy Meyerhoff, a biologist aide at the Patuxent research center, asked him to make the eggs because three whooping cranes began over-producing eggs and breaking and eating them.
Being in pens instead of their normal habitat makes the cranes nervous and edgy, often causing such behavior, experts said. Being surrounded by humans also may affect their natural behavior.
There are a total of 40 whooping cranes, or "whoopers," and six chicks at the center.
In the past, the center used sandhill crane eggs filled with plastic and plaster to keep the whooping cranes from eating their own eggs, said George Gee, leader of the $300,000 Captive Propagation Research Center for whooping cranes. Those tricks usually worked for other birds, but not for the whoopers, he said.
"The whooping cranes were eating and destroying the plastic and plaster ones so we went to the wooden ones," Gee said. "They beat on them for a while; when they couldn't break them, they accepted them."
Gee added that the staff considered using a marble egg, but thought that would be too heavy.
"What they needed was something to fool the adult birds," Lindvall said.
And they did.
Gee said the wooden eggs have already fooled two of the three birds.
The birds' real eggs are placed under sandhill cranes to hatch. Sandhill cranes are similar birds, but have better maternal instincts, Gee said.
The wooden eggs, meanwhile, stay under the troubled whooping cranes for 30 days, the normal incubation period. When a sandhill crane's egg is ready to hatch, staffers place it under the whooping crane so she can hatch it and care for it, Gee said.
Gee said the whooping cranes must incubate a non-endangered egg three times before the center will allow them to raise their own chicks.
Lindvall said it takes about 15 minutes to make the wooden eggs at a shop in his home. Most are about 3 inches long.
To date, he has made six bogus eggs at no charge to the research center. And he says he'll make more if they're needed.
At the Patuxent research center and other captivity centers, whooping cranes now total about 230 in the U.S. and Canada, Gee said. In 1941, there were only 13 left in North America.
In 1967, the Patuxent center received whooping crane eggs from Canada's Wood Buffalo National Park and artificially incubated them. Twelve eggs hatched, establishing the center's captive flock.