Nearly a third of the nation's 800 bird species are endangered, threatened, or suffering from population decline, according to an Interior Department report cited in today's NYTimes online. In recent decades the known culprits have included destruction of habitat, hunting, pesticides, invasive species and the loss of wetlands. Both the Audubon Society and the Cornell Lab of Ornithology have reported alarming declines in the numbers of both resident and migratory birds during the decade since 2000.
The current State of the Birds Report adds climate change to the list for the first time. Rising sea levels associated with global warming cause rapid fluctuations in marine ecosystems. These same ecosystems are not only home to a large number of oceanic and shore birds, but also act as a valuable filtering mechanism which prevents sediment and human contaminants from reaching the global ocean.
Their loss is one more among the cascading impacts which humans have on the environment, as well as something more -- a bellweather, like the canary in the coal mine, a warning that we continue to unleash forces which we cannot control. We ignore such warnings at our own peril.