Originally Posted by Glen Tepke
...My definition of a birder is someone who goes out of their way to look for birds. If you include people who feed birds but do not engage in other birding activities, the numbers would be much higher.
If you apply the 0.03% estimate to the US population (293 million), you get 88,000 regular birders. Even if this number is wrong by a factor of ten, you would have to be using an extremely loose definition of birder to come up with 70 million or even 30 million.
The USFWS Survey
The link that I posted above [ http://fa.r9.fws.gov/surveys/surveys.html
] allows for one to download the survey report as well as state by state reports and has information regarding the surveying techniques.
Roughly summarizing: The survey was carried out in two phases. In the first phase (April of 2001 for the 2001 survey) "the US Census Bureau interviewed a sample of 80000 households nationwide to determine who in the household had fished, hunted or engaged in wildlife-watching activities in 2000, and who had engaged or planned to engage in those activities in 2001. ... The second phase of the data collection consisted of three detailed interview waves. The first wave began in April 2001, the second in September 2001, and the last in January 2002. Interviews were conducted with samples of likely anglers, hunters, and wildlife-watchers who were identified in the initial screening phase. These interviews were conducted by telephone, with in-person interviews for those respondents who could not be reached by telephone.... Altogether, interviews were completed for 25070 respondents from the sports persons (anglers and hunters) sample and 15303 from the wildlife-watchers sample."
Thus it seems to have been a careful and well planned effort. It is when people start using poorly defined terms, such as birders, that confusion enters. Wildlife-watcher is a broad but well defined term that includes the following activities: observing, photographing and feeding wildlife but it avoids questions such as "How many different species can you identify?" etc. That is how the big numbers, in tens of millions appear. In the suburban neighborhood where I live I can see bird-feeders every five or six houses in a morning's walk with my dog. Obviously there are a lot of people who feed birds in their backyard. Thank Gaia that not all those people decided to purchase binoculars and hit the local birding spots!