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For the birds
Thousands of volunteer citizen-scientists across our region this winter will be keeping an eye on bird feeders for signs of West Nile virus and the impact of acid rain and global warming on birds. Since 1987, the Cornell Lab of Ornithology has asked bird enthusiasts of all ages, skill levels and background to record the numbers and kinds of birds that visit feeders from November through early April. Researchers then analyze the data to determine changes in populations, distribution and abundance of over 100 species of birds. Crows and blue jays were among the first species known to be affected by West Nile virus, but more than 110 species of birds have been infected. According to the Centers for Disease Control and Prevention, crows have been the most obvious victims of West Nile virus because of their size, but uncounted numbers of smaller birds have also succumbed to the virus, but their bodies are less frequently found by health authorities. Another study at Cornell, funded in part by the National Science Foundation, has shown that tree swallows, a very common species in western New York, may be laying eggs as much as a week earlier because of warmer temperatures over the past 30 years. When tree swallows start earlier they often lay more eggs, according to David Winkler, a Cornell professor of ecology and evolutionary biology. "We don't know whether earlier lay dates and larger clutch sizes will be good in the long term for populations of tree swallows," says Winkler, "And tree swallows are just one of the many organisms that potentially can be affected by climate change." Tree swallows are acute weather indicators for three reasons, Winker says.
Acid Rain The widespread decline of all songbirds in recent years has been linked for the first time to acid rain. Using data collected by the volunteers in the citizen-scientist program, Cornell scientists at the Ornithlogy Lab have determined that the wood thrush, in particular, is less likely to breed in regions that receive high levels of acid rain. The study was reported by the National Academy of Sciences. Aside from the decline in bird numbers, the study also confirms findings first found in Europe that acid rain leeches calcium from the soil, thereby depleting an essential nutrient for plants and birds who depend on them for food. The scientists do not yet fully understand exactly how the acid rain and soil calcium deficiency impacts bird populations, but they suspect other species besides the wood thrush are similarly affected. Acid rain is the broad term used to describe a solution of nitric and sulfuric acid that falls out of the atmosphere as rain, snow, mist and fog. In the USA, two-thirds of sulfuric acid and one-fourth of nitric acid come from coal-burning electric power generating plants. In New York, higher elevations of the Adirondacks, Allegheny and Appalachian mountains receive the highest amounts of acid rain. Mid-western electrical power generating plants that burn coal and other fossil fuels are thought to be the source of acid rain in New York. Top 10 feeder birds For info |