Surely you have heard reports about birds that are threatened by environmental changes. But it is not just far-off rainforest species or pole-dwelling penguins that face an uncertain future many less exotic North American birds are experiencing significant drops in numbers. In fact, 20 common North American bird populations have been cut in half in just four decades, according to the latest installment of the Audubon Society report Common Birds in Decline. These birds in danger have earned the unfortunate distinction of a spot on Audubon list: American Bittern, Black-throated Sparrow, Boreal Chickadee, Common Grackle, Common Tern, Eastern Meadowlark, Evening Grosbeak, Field Sparrow, Grasshopper Sparrow, Greater Scaup, Horned Lark, Lark Sparrow, Little Blue Heron, Loggerhead Shrike, Northern Bobwhite, Northern Pintail, Ruffed Grouse, Rufous Hummingbird, Snow Bunting and Whip-poor-will. Every bird situation is different, but a common culprit lurks behind virtually all of the nose-diving numbers: humans and their activities. Mile upon square mile of prime Eastern Meadowlark habitat has been lost to housing, industry and farming. The tundra-dwelling Greater Scaup is under pressure from human-caused pollution and climate change, which affects ecosystems in its breeding grounds. And the Boreal Chickadee suffers from deforestation caused by excessive logging, drilling and mining, according to Audubon. While none of these species is in imminent danger of extinction, the report is a reminder that perhaps we ought to pay attention before they arrive at the brink. "This is not extinction, but it is how things look before extinction happens,"wrote Verlyn Klinkenborg of The New York Times after the Audubon report came out. It is partly due to the work of "citizen scientists" bird-watching volunteers that Audubon is able to reliably track bird numbers year after year. If the declines are to be reversed, it is also up to citizens. Audubon suggests taking steps that range from local (preserving habitats) to global (fighting global climate change) to avoid a much longer, bleaker version of what Rachel Carson famously termed a "silent spring." Learn more at the Audubon Society's Common Birds in Decline page.
The Dodo Bird
The dodo(Raphus cucullatus)is an extinct flightless bird that was endemic to the island of Mauritius, east of Madagascar in the Indian Ocean. Its closest genetic relative was the also extinct Rodrigues solitaire, the two forming the subfamily Raphinae of the family of pigeons and doves. The closest extant relative of the dodo is the Nicobar pigeon. A white dodo was once incorrectly thought to have existed on the nearby island of Reunion. Subfossil remains show the dodo was about 1 metre (3 ft 3 in) tall and may have weighed 10.6-21.1 kg (23-47 lb) in the wild. The dodo appearance in life is evidenced only by drawings, paintings, and written accounts from the 17th century. Because these vary considerably, and because only some illustrations are known to have been drawn from live specimens, its exact appearance in life remains unresolved. Similarly, little is known with certainty about its habitat and behaviour. It has been depicted with brownish-grey plumage, yellow feet, a tuft of tail feathers, a grey, naked head, and a black, yellow, and green beak. It used gizzard stones to help digest its food, which is thought to have included fruits, and its main habitat is believed to have been the woods in the drier coastal areas of Mauritius. One account states its clutch consisted of a single egg. It is presumed that the dodo became flightless because of the ready availability of abundant food sources and a relative absence of predators on Mauritius.
[source: National Geographic]