California Condor Feathers Tell Harrowing Tale of Struggle and Survival: Guest post by Alex Tamura
The Wiyot Tribe of Humboldt Bay describes the origins of mankind through a tale of survival and rebirth. The creator of all things, Gouriqhdat Gaqilh, had become weary of the wicked ways of man and summoned a deluge to drown the Earth and destroy all living things. The sole survivor was the great Wiyot hero Shadash, or Condor, who started a new civilization cleansed of evil.
In 1860, about 100 Wiyot people were massacred while celebrating a ceremony honoring that tale of rebirth and survival. Like Condor, the tribe’s survivors endured. Today, the Wiyot still see condors—and condor feathers—as symbols of renewal. Recently, they performed their first World Renewal Ceremony in more than 150 years, with a gift of 48 condor feathers from the Sía Essential Species Repository. However, the jet-black plumage provides a glimpse into another story of survival—this time for the birds themselves.
These condor feathers reveal the chemical traces of lead poisoning, a serious continuing threat to the population in California. Despite decades of progress, scientists still intensively manage the birds in the wild and continue to treat the ones exposed to lead. A new state law offers hope that the birds may endure for centuries, but lead poisoning—once unseen and unappreciated—continues to play a part in their private lives today.
UC Santa Cruz toxicologist Myra Finkelstein is one of the researchers using feathers to tell this story. “Analyzing their feathers has really become a powerful way to understand what’s going on with these birds when they’re out there in the wild,” Finkelstein says.
The California condor is one of North America’s most impressive and rare birds. It is the largest land bird on the continent, with a wingspan stretching nearly 10 feet. Wild condors can soar as high as 15,000 feet, and they fly up to 120 miles per day. With their large, cherry-colored eyes, the bald-headed birds scrupulously survey the terrain looking for carcasses of deer, cattle, and other animals. They devour carcasses, or carrion, with razor-sharp beaks, and they can store up to three pounds of meat in a part of their esophagus called a crop. Although these scavengers can survive two weeks without a scrap, they rarely have to because they have complementary admission to an all-you-can-eat buffet at feeding spots high in the back country, courtesy of researchers.
In 1987, the International Union for Conservation of Nature designated the birds “extinct in the wild.” Conservationists placed all 22 known California condors into captive breeding programs at the Los Angeles Zoo and San Diego Zoo. In 1992, researchers reintroduced the condors to the wild and nurtured the population back to more than 400 birds. Today, more than half of these condors are free-flying in California and nearby states, but they are still “critically endangered”—largely due to lead poisoning.
Survival has not been easy. Wild condors produce only one egg per clutch, and it takes them about six years to reach sexual maturity. This makes their population especially vulnerable to environmental hazards, such carrion contaminated by DDT, power lines, wind turbines, and microtrash: bottle caps, wires, and bullet casings. However, lead poisoning poses the greatest threat.
In one study, scientists at the Minnesota Department of Natural Resources showed that lead bullets can fracture into tiny fragments, wildly scattering throughout an animal’s tissue like toxic hail. Only a few fragments are enough to poison a condor—equivalent to a few grains of sand. Condors unwittingly swallow these pieces after dining on unretrieved carrion killed by hunters.
Once this lead enters the bloodstream, it migrates into the birds’ tissue, bones, and feathers. Lead exposure irreversibly destroys the myelin sheath that protects sensitive nerves, setting off tremors and impairing coordination. Severe poisoning can shut down the digestive system. The only way to remove the lead is by flushing it out of their blood with chelation therapy, which binds the contaminant with a drug. But often, the damage is already too great.
Evidence that lead ammunition was harming condors first came from a UC Santa Cruz study in 2006. Environmental toxicologist Donald Smith and former graduate student Molly Church found that the blood-lead concentration of condors released in the wild had increased tenfold since they were in captivity. They determined that such severe lead poisoning could only arise if a bird had eaten lead and that the lead came from locally purchased bullets. In 2008, lead ammunition was banned in all condor ranges within California.
Even with the ban, things haven’t improved. “At least half of them have been lead poisoned and have had to be treated at the L.A. Zoo,” Finkelstein says. Today, paired with blood-lead analysis, tracing lead exposure through feathers has become a powerful research tool. Each condor is tested for lead at least twice a year—more frequently if the bird recently suffered from lead poisoning. But blood tests can only show the bird’s current lead poisoning. A single fully grown feather can reveal the bird’s lead exposure from the previous four months.
Testing the feathers require some high-tech tools. Researchers digest small pieces of a feather with acid, then pump it into an inductively coupled plasma mass spectrometer. This instrument uses a high-energy beam of electrons to ionize the feather solution with temperatures comparable to the surface of the sun. Now ionized, the feather atoms get sorted within a magnetic field, according to their mass and charge. A detector zeroes in on each sample, quantifying the feather’s lead.
Like human hair, feathers contain mostly carbon, nitrogen, oxygen and hydrogen—the essential building blocks of life. But when a condor has eaten lead, large amounts of the heavy metal show up in its feathers. This painstaking approach allows Finkelstein to measure the degree of poisoning during the months before the blood tests.
“We’re realizing that the blood monitoring isn’t even catching the tip of the iceberg for the degree of lead exposure,” Finkelstein says. “Even though the blood monitoring shows the lead exposure is of epidemic proportions and that they’re chronically poisoned, the feathers show that it’s way worse.” She found that one-fifth of free-flying condors have near-lethal or lethal blood-lead levels. And according to her population model, condors will only successfully recover when lead is completely removed from the equation. “The number of birds born just doesn’t make up for the number of birds that die. That’s what needs to change,” Finkelstein says.
She and a collaborator are now improving the model to predict how lead poisoning impacts condor breeding and how hazards such as microtrash affect the birds as a group—as well as other animals. “Condors might serve as a canary in the coal mine for other species that we aren’t actively tracking on a daily basis, but who are also foraging on animals shot with lead,” Finkelstein says.
The birds have a generously funded and well-staffed support system, which many other species don’t have. Scientists track condors using radio and GPS transponders. Indeed, the program’s researchers are daring adventurers, flying near treacherous ranges, and rappelling into unexplored ravines to find injured, poisoned, and deceased condors. The team performs full necropsies on each dead condor they recover to determine its cause of death.
“We know that other species are dying from lead poisoning, but we can make the link even stronger with the condors,” Finkelstein notes. “The amount of hands-on knowledge we’ve gained from them is phenomenal.”
California condors also have new allies who don’t need to leave home to find adventure: citizen scientists. Using the online Condor Watch program, condor fans can explore more than 170,000 photos taken at feeding stations. This helps researchers keep track of the birds and their wildlife neighbors, such as mountain lions, bears, and feral pigs. With each click, users can discover tidbits about each tagged condor. For instance, condor #32—the son of #42 and #39—was hatched in 2004 at the L.A. Zoo and is “still kickin’.” Aspiring condor aficionados can aid scientists and learn about their new feathered friends at the same time.
The scientific studies and public support are making a difference. In late 2013, California Gov. Jerry Brown signed AB 711 after reviewing expert testimonies and the results of Finkelstein’s research. The bill will ban all lead ammunition in California by 2019, marking a transition into a safer era for condors and other scavengers.
At least that is Finkelstein’s hope. She believes that the new law, alternative hunting ammunition, and increased public outreach through programs like Condor Watch will help the California condor population grow, stabilize, and thrive. But the threat of extinction is still very real. Californian zoos and organizations continue to treat lead-poisoned condors with chelation therapy. Despite the odds, the California condor may survive its own near extinction, much like its heroic namesake and the Wiyot people that revere them both.
Alex Tamura, an undergraduate majoring in astrophysics at UC Santa Cruz, wrote this story in spring 2014 for SCIC 160: Introduction to Science Writing.