Over the past five millennia, some 500 bird species have faced the danger of extinction, many of which have already gone extinct. The rate of extinction is expected to increase during the 21st century. Human influences, including but not limited to habitat destruction and selective hunting have endangered bird species as well as other animal species. In addition to human threats, natural causes such as global warming are driving avian species towards extinction. If humans continue with their current trend in altering the natural environment of birds, the extinction rates are estimated to rise in the order of ten additional species per year.
Though many bird species are at the brink of extinction, human love for the birds has fortunately placed special attention towards preservation of bird species. Human interventions have saved a number of bird species that were once endangered. Conservation efforts have resulted in the reduction of the extinction rates of threatened bird species. In fact, some of these bird species have made a marked comeback after being nearly extinct.
Hunting, habitat loss and pesticide use once placed the Bald Eagle at the verge of extinction. In 1963, the Bald Eagle population reduced to about 400 breeding pairs in the U.S. As a result, the Bald Eagle was declared an endangered species by the American government in 1967. Wide use of the pesticide DDT (dichlorodiphenyltrichloroethane) was the main cause of the drop in the Bald Eagle population. DDT prevented adult female birds from laying healthy eggs.
Due to intensive conservation efforts, the Bald Eagle has made a successful comeback. Since 2007, the species is no longer listed as an endangered species as the Bald Eagles have successfully recovered. Today, there are more than 10,000 breeding pairs in the lower 48 states of the U.S.
Kirtland’s Warbler has strict habitat requirements, including old jack pine stands. Fires play an important role in the regeneration of old jack pine forests. Germination of jack pine seeds are aided by forest fires. Kirtland’s Warbler also needs sandy soil for nesting. The soil where the jack pine occurs is well drained and sandy with little humus.
Suppression of forest fires, and competition for nest space with the parasitic cowbirds disastrously affected the population of Kirtland’s Warbler. The result was a significant decline in the Kirtland’s Warbler population (about 210 breeding pairs in 1971). However, massive conservation measures helped the bird population to increase (1415 breeding pairs in 2005). The rare avian species has made a comeback after being nearly extinct. At present, thousands of acres of public land have been reserved for their management.
The Whooping Crane, tallest flying North American bird, has made a comeback after facing the danger of extinction. In the 1940s there were about 21 birds in the wild. Destruction of wetland habitats, predation, power line collisions and illegal shooting drastically led to the decline in Whooping Crane population.
Conservation efforts which began in the U.S. and Western Canada in 1938 have led to the gradual increase in the population of Whooping Cranes. The species has been successfully introduced to its winter home in Florida. Today, there are about 599 whooping cranes in the wild and in captivity. Though the population of Whooping Cranes is increasing, the species is still endangered.
The Australian Regent Honeyeater which feeds mainly on nectar from a few eucalypt species is a critically endangered species. The population of Regent Honeyeaters has rapidly dropped over the past 24 years. Habitat loss is the main reason for the decline in Regent Honeyeaters’ population. Other factors include drought and competition with other native species. Regent honeyeaters which were once found within the Southern Australian coast no longer occur in Southern Australia.
In order to save the Regent honeyeater, the species have been bred in captivity and released into the wild. Such conservation efforts have been successful as most of the birds bred in captivity and then released into the wild survived and adapted in the wild. The Australian Regent Honeyeater is indeed making a definitive comeback.
In the 1900s the Brown Pelicans were hunted for their feathers. Commercial fishers also killed the Brown Pelicans as they misguidedly thought the birds threatened their fisheries. In addition, the loss of coastal habitats had led to the decline in Brown Pelican population. While the Brown pelican population was decreasing, extensive use of pesticides such as DDT pushed the species towards extinction. DDT caused thinning of the birds’ egg shells which resulted in their destruction during incubation periods.
Since the Brown Pelican was listed as an endangered species in the 1970s, measures have been taken to conserve the species. The collective efforts made to save the Brown Pelican have prevented the species from going extinct, which also allowed the birds to make a comeback. Though the Brown Pelican has been removed from the list of endangered species, the birds are still affected by oil spills.