In 2007 the National Audubon Society, one of the leading environmental organizations in the United States, issued a report headlined “Common Birds in Decline.” Based on statistical analysis of 40 years of bird population data, it announced “the alarming decline of many of our most common and beloved birds.”
The story attracted wide press coverage. “Spreading suburbs and large-scale farming are contributing to a precipitous decline in once common meadow birds,” began a New York Times story. An accompanying editorial lamented, “We somehow trusted that all the innocent little birds were here to stay. What they actually need to survive, it turns out, is a landscape that is less intensely human.” A letter to the editor predicted that the deadly pattern will continue “as long as we ask the earth to support too many people.”
Few commentators bothered to study the study itself. Had they done so, they might have noticed that among 309 bird species for which statistically meaningful trends could be established from data in two population surveys, birds showing a “large increase” exceeded those showing a “large decrease.” Forty-one species recorded a large increase in both surveys; only twelve saw a large decrease.