Growing piles of rubbish lie untreated at 11 open-air dumps in the general vicinity of the airport in Salvador, Bahia. The dumps nourish expanding populations of vultures. Many of these birds venture into flight patterns. The number of reported collisions between airplanes and birds in Brazil has more than doubled in a decade – from 166 in 1994 to 441 in 2004. Through the end of August, 243 incidents had been reported in 2005. (Officials estimate that less than one-quarter of all collisions are reported.) While accidents involve many different kinds of birds, the black vulture (Coragyps atratus) accounts for more than half of the cases in which the species can be identified.

As aviation expands, the number of aircraft collisions with birds is growing around the world. The difference in Brazil is the role played by inadequate sanitation and environmental degradation. “In the United States and Europe, the problem is usually with migratory birds,” said Air Force Major Flávio Coimbra, coordinator of the Avarian Danger Taskforce at the military Center for the Investigation and Prevention of Aircraft Accidents (CENIPA). “In Brazil, the problem is the role of humans in the environment.”

The dumps that surround Salvador are more the rule than the exception in the country’s poor Northern and Northeastern regions. In Recife, Pernambuco, a major dump sits just eight kilometers from an airport once considered to be on the outskirts of town but now surrounded by urban sprawl. In Teresina, Piauí, a clandestine chicken slaughterhouse seeking to evade municipal fees set up shop near the airport and began discarding its leftovers in an adjacent vacant lot. In Paulo Affonso, a city of 100,000 in Bahian outback, a leatherworks factory near the airport was

 caught disposing of its organic waste in a similar fashion. In Macaé, on the coast 200 kilometers north of Rio de Janeiro, helicopters that transport workers to nearby off-shore petroleum rigs are troubled by vultures attracted by the scraps abandoned by fishermen when they clean their catches. In many cities, favelas (shantytowns) with inadequate sanitation engender rats that in turn attract the birds of prey. “The problem is one of human overpopulation or the inability to take care of waste,” said Wagner Fischer, a biologist and coordinator of the wildlife management department at IBAMA, the Brazilian federal environmental oversight agency.

Big by bird standards, weighing from 17-30 pounds, even a vulture wouldn’t seem to pose much of a threat to a huge airliner. But given the velocity at which the collisions take place, the impact can be equivalent to seven tons of force. Airline carriers and the Brazilian military suffered material damages of about $2 million in 1994. The country has yet to record a fatal accident – though twice since 2003 pilots were injured by birds that crashed into their windshields and were forced to make emergency landings under duress. (Some countries, including the United States, have not been so lucky: all 24 crew members died at the Elmendorf Air Force Base in Anchorage, Alaska, when their E-3 ASWACS collided with a flock of geese in 1995.)

In Brazil’s relatively more affluent South and Southeast, sanitation is less of an issue. There the southern lapwing (vanellus chilensis or “quero-quero” in Portuguese), which inhabits wetlands areas, ranks first among crash victims. The Curitiba airport was forced twice in a single week recently to shut down its runways because of a southern lapwing invasion.

Forced by urban sprawl to flee former habitats, the southern lapwing finds refuge in the lawns that surround many airports. At the Rio de Janeiro international airport, “all the surrounding land is occupied,” said Giovannini Luigi, a biologist with the Avifauna and Airports Research Center. “With four million square meters of grass at the airport, the birds have found paradise – an urban oasis.”

Ironically, environmental conservation efforts appear to play a role in the growing number of collisions. Of the 66 airports run by Infraero, a state-owned civil aeronautics company, 28 are located in or around environmentally protected areas. Fleeing urban sprawl, many species of wildlife migrate to these areas near airports on the outskirts of town. “With the increase in green belts, these conservation areas have become magnets for many species,” said Luigi.

Luigi heads up a team hired by Infraero to study the problem and suggest solutions at major airports. So far scientists have visited about two dozen. They have made specific suggestions at each site and developed an as yet unreleased manual for airport administrators. They are also working with Rio de Janeiro’s three biggest airports on a pilot program to develop wildlife management plans.

The growing number of incidents has brought calls for killing birds and eliminating nests. Such actions would require authorization from IBAMA. The agency had until recently handled requests on a case-by-case basis, albeit clearly favoring relocation over elimination. In Natal, the agency transferred 3,000 vultures more than 200 kilometers away in an operation that took several months and ended last year. In August IBAMA published a blanket regulation that requires airport administrators to consider non-lethal options and produce a wildlife management plan before it will contemplate more extreme options.

Neither killing the birds nor relocating them is a long-term solution, agree officials. Though only 3% of the relocated vulture population returned to Natal, other birds have multiplied to occupy the abandoned niche because many of the environmental and sanitary problems have not been adequately addressed. A joint inter-governmental and industry panel, coordinated by CENIPA, is organizing a series of regional seminars for local officials, who generally take the bulk of responsibility for sanitation and land use policy.

“What if you have a bunch of house flies in your home?” asked IBAMA’s Fischer. “Is it better to kill or relocate the flies or clean your house?”

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