Could the same apply to some birds? A number of scientists are trying to figure this out, and there's a growing body of research looking into the effect of electromagnetic fields on bird reproduction. A few years ago Denis Henshaw, professor of physics at Bristol University, carried out tests where the egg-laying ability of chickens was effected by electromagnetic waves. Of course, this doesn't shed much light on why some native bird species are effected more than others, and it doesn't explain the considerable decline in house sparrow populations before 1994, the year that witnessed the beginnings of today's mobile phone boom. According to critics, mobile phone masts have simply joined unleaded petrol, cats, grey squirrels, loft installation, and changing farming and building practices on the list of likely -- or unlikely -- suspects. Even the British Trust for Ornithology isn't 100 percent convinced, pointing to that fact that other native birds -- such as blue tit, great tit, robins and blackbirds -- all live and breed in the same habitat as sparrows, yet show no sign of rapid decline.

As with studies on the effect of radio waves on human health, it is unlikely there will be consensus on their wider risk to the environment any time soon. But if you're in any doubt about how "busy" it is up there, one look at the wireless spectrum is enough to give you a headache. The airwaves -- extremely valuable real estate in today's wireless, digital world -- are literally packed with chatter and noise, much of which is passing silently through our bodies every minute of every day. Even though you and I may not notice it, there's every chance that the birds and the bees do.

Ken Banks, founder of kiwanja.net, devotes himself to the application of mobile technology for positive social and environmental change in the developing world and has spent the last 15 years working on projects in Africa. Recently, his research resulted in the development of FrontlineSMS, a field communication system designed to empower grassroots nonprofit organizations. Ken graduated from Sussex University with honors in Social Anthropology with Development Studies and currently divides his time between Cambridge (U.K.) and Stanford University in California on a MacArthur Foundation-funded fellowship. Ken was awarded a Reuters Digital Vision Fellowship in 2006 and named a Pop!Tech Social Innovation Fellow in 2008. Further details of Ken's wider work are available on his Web site.