In Galapagos Islands, Sizing Up Avian Perils
Special to The Washington Post
Monday, September 23, 2002; Page A09
PUNTA CEVALLOS, Galapagos Islands -- Diego Santiago slowly reached the long pole up the rocky slope and slipped the noose around the hawk's neck. A step behind Santiago, the slope dropped 100 feet to crashing Pacific waves.
The hawk, inquisitive at first, suddenly tried to take flight when the noose tightened. But Santiago swung the bird down to the waiting, gloved hands of Patty Parker.
"Perfect," said Parker, a biologist with the University of Missouri-St. Louis and the St. Louis Zoo. Santiago, one of her graduate students, removed the noose as Parker settled the flapping hawk, placed a cotton bag over its head and covered its talons with masking tape.
Parker, Santiago and Luis Padilla, a veterinarian based at the zoo, proceeded to draw blood from the hawk, dust it for lice and swab its throat for bacteria.
This scene in July on the southern coast of Espanola, one of the Galapagos Islands, was part of a new effort to avert a looming biological catastrophe on one of science's most hallowed grounds.
Parker and her colleagues aim to prevent a tidal wave of alien diseases from washing over the hawks and other native birds here -- which happened in Hawaii, where pathogens have decimated the state's forest birds. The scientists are surveying the health of native and nonnative birds throughout the Galapagos, the archipelago whose curious creatures inspired Charles Darwin to develop his theory of evolution based on natural selection. The Galapagos Islands are an Ecuadoran national park and a United Nations World Heritage Site.
The researchers want to find out what diseases the birds have and whether those diseases present problems. They also want to establish an early warning system to signal the arrival of a new threat, possibly including a "sentinel species" whose illness would be readily detectable.
"To date, we haven't had any species of bird go extinct in the Galapagos," said Howard Snell, a biologist with the University of New Mexico and the Charles Darwin Research Station in the Galapagos. "But we're trying to get ahead, to be ready, to have the knowledge that's necessary to identify new diseases that come in."
Knowing when a potentially devastating disease arrives, Snell and others said, is the first step in figuring out what to do about it. This summer, they accelerated their cooperative bird disease survey, begun last year.
The Galapagos Islands have had their share of environmental problems recently.
An oil spill in January 2001 led to the slow deaths of thousands of the islands' unique marine iguanas, scientists say. A diesel fuel spill in July 2002 apparently killed fish, crabs and other sea creatures.
Overfishing has plagued the park's marine reserve. The illegal taking of sea cucumbers and shark fins for the Asian market has been particularly devastating, they say.
The most serious ongoing threat is damage to island ecosystems by such alien species as goats, cats, invasive plants and rats.
Lurking in the background is the frightening example of Hawaii, the prime example of ecological disaster on oceanic archipelagos.
"Hawaii is the model of what can go wrong," said Eric Miller, director of animal health and conservation at the St. Louis Zoo and co-leader of the disease survey. The 50th state accounts for less than a quarter of 1 percent of U.S. landmass but more than half its extinctions, Miller said. Only 28 bird species remain of the estimated 88 that lived in Hawaii when the Polynesians arrived.
Some of the native Hawaiian birds were killed and eaten, but most fell to introduced predators, diseases or deforestation after Western contact in 1778. In recent decades, avian malaria has spread widely. The reason native forest birds only survive 4,000 feet above sea level -- on any of the Hawaiian Islands -- is that mosquitoes don't live any higher.
Animals on remote oceanic islands are susceptible to introduced diseases because they evolved without these threats and didn't have to develop defenses. In some respects, researchers say, the birds of Hawaii and the Galapagos are like 19th-century native Americans handed blankets contaminated with smallpox.
Even though none of the 26 Galapagos land-bird species has yet to be pushed near extinction by disease, recent events have sent a shudder through Galapagos conservationists. The Culex mosquito, which is known to transmit avian malaria, has been reported in the islands. And last year, the bird disease survey found several finches and domestic chickens with pox virus sores.
"You have this priceless collection of animals out here, none of which has gone extinct," Parker said. "And you have the arrival of the possibility of two diseases directly tied with the massive extinction that hit the Hawaiian avifauna. That made us extremely nervous and prompted our survey."
Collaborating on the survey with the university and zoo are the Darwin station, Galapagos National Park and Hawaii Field Station of the National Wildlife Health Center, in Honolulu. St. Louis philanthropist Des Lee has funded most of the project. The researchers hold workshops for Ecuadoran scientists on identifying diseases. The zoo has stationed Timothy Walsh, a veterinary pathologist on leave from Washington State University, in the Galapagos for a year.
For the second summer in a row, the scientists fanned out on several of the islands to sample blood and tissue from hundreds of hawks, waved albatrosses, Galapagos doves and other native birds. They also sampled introduced birds, such as chickens, pigeons and smooth-billed anis, all of which could transmit diseases to native birds.
The young male hawk noosed by graduate student Santiago was an especially important catch. Hawks are at the top of the island food chain, so if any bird species is carrying a disease, there is a good chance the hawk will have been exposed. Juvenile hawks are more likely than adults to be infected.
The blood drawn from the hawk will be checked for a wide range of microorganisms, from West Nile virus to malaria parasites. Some will be sent to labs for blood counts and chemistry analysis to determine the overall health of the bird. The lice sample also will indicate the bird's health.
Swabs of the throat and cloaca -- the excretory and reproductive opening -- will be tested for salmonella, trichomoniasis and other pathogens.
If a potentially catastrophic disease is discovered this year or in the future, park managers will have to decide what steps they can take to prevent its spread. One possibility is to quarantine imported domestic birds that may be carrying the pathogen.
"There's a lot you can do about wildlife diseases," said Thierry Work, a veterinarian with the U.S. Geological Survey's wildlife health center in Honolulu and member of the Galapagos research team. "But you can't do any of that if you don't know what diseases exist."
© 2002 The Washington Post Company