Columnist Paula DelGiudice: Changes in climate affect bird populations

Paula DelGiudice

Thursday, March 14, 2002 | 10:32 a.m.

Paula Del Giudice's outdoors column appears Thursday. She can be reached at desertdenizens@aol.com.

The fact that global warming, also known as climate change, is real and under way can no longer be explained away as hysteria or fear mongering by radical, left-wing environmentalists.

According to a recent report issued by the National Wildlife Federation and the American Bird Conservancy, "There is overwhelming agreement among the world's preeminent scientists and scientific bodies that the Earth is heating up and human activities are largely to blame."

The report undertaken by the organizations attempts to quantify the affects of climate change on bird populations. There is evidence that the late-20th century pattern of global warming is already having an effect on wildlife, including birds.

Since songbirds play a critical role in ecosystems by eating insects, pollinating plants and dispersing seeds, such changes risk throwing ecosystems off balance.

What kind of changes does the report predict will happen? As regional temperatures rise, the climatic ranges for a number of species may shift north as they seek habitat, food availability and other factors to which they are adapted. In turn, in the ranges they leave behind, the birds may be replaced by species from farther south.

The report points out that when some species move to different ranges, "they may face new prey, predators and competitors, as well as different habitats.

"New York could see a significant reduction in suitable climatic range for Cape May Warblers, Bay-breasted Warblers, and other birds that are important predators of pest insects such as eastern spruce budworms, which can cause major damage to the state's forests.

"Arizona, Nevada, and New Mexico could lose Savannah Sparrows, Sage Thrashers and other birds that help keep outbreaks of rangeland grasshoppers in check.

"And some states may even lose their State Bird. If global warming continues unabated, there may no longer be Orioles in Baltimore (or anywhere else in Maryland). At the very least, the range of the species in Maryland may be greatly reduced."

If changes occur in Nevada in line with the climate change models developed by the Canadian Climate Center, there are species whose future climatic range may exclude Nevada in the summer, such as the Dusky Flycatcher, the Gray Flycatcher, the Bank Swallow, the Black-capped Chickadee, the Common Yellowthroat, the Sage Sparrow, the Savannah Sparrow, the Fox Sparrow, Dark-eyed Junco and Cassin's Finch.

The following include species whose climatic summer ranges in Nevada might contract: the House Wren, Sage Thrasher, Western Tanager, Blue Grosbeak, the Green-tailed Towhee, Chipping Sparrow, Brewer's Sparrow and Yellow-headed blackbird.