People often dislike vultures because these birds eat the remains of dead animals. Without vultures, however, dead bodies of animals can rot and cause other animals and people to get sick. One member of this family, the California condor, has been important in cleaning up dead bodies of animals from the beaches and mountains of western North America.
But by 1979, few condors could be found in the wild. One explanation for their decrease was the presence of power lines. Condors are the largest flying land birds in North America. When these large birds hit power lines, they can die from electric shock.
Power lines explained only some of the decline in the population. Many of the eggs in condor nests were broken. Closer examination showed that the shells of eggs were not as thick as they had once been. Since these birds lay eggs on hard surfaces like rocks, thin shells meant that eggs cracked easily.
Scientists found a chemical in condors that explained the thinner shells. The chemical had been used to kill insects that destroy crops. Broken eggs are especially a problem for condors because their eggs are rare. Females only start laying eggs at six years of age. Further, they lay only one egg at a time and not every year. Broken eggs meant no new condors.
By 1987, only 27 condors remained. All were in zoos or breeding centers. Eggs were sheltered from harmful chemicals in these places. Thicker shells meant that healthy chicks hatched from the eggs. As more chicks survived, the number of condors grew.
In the 1990s, condors began to be released into the wild. In 2017, 276 condors were in the wild—ten times more than the population of 30 years ago. Many challenges still remain for the survival of these birds but their reappearance in the wild shows what can happen when people work to solve problems.
