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Message: <blockquote data-quote="Hauksen" data-source="post: 3597467" data-attributes="member: 142861">Hi,For analysis, it might be useful to look at the way radio signal strength decreases with distance. Radio waves are undetectable to natural human senses, but they have a lot of common with sound signals, which we understand well due to our everyday experience.A radio tower can be compared to a bell tower: The signal strength is very great directly at the source. Imagine being on a church tower when the bell rings! It is still very impressive nearby (such as standing in front of the church), loud enough to interfere with other signals (such as speech, or musik) two or three streets off, but the farther away you are, the fainter the signal becomes - though it can be heard from a very long distance away if there are no interfering signals (such as traffic noise).So if you're looking at a situation where there is a decrease of birds uniformly all over a large area, I would think that it's not necessarily what one would expect from localized sources. It would seem more likely that where radio waves are a factor, you would see a clear impact right around the radio tower,  only a much weaker impact a certain distance away from it, and next to nothing a fair distance off.(As far as humans are concerned, radar technicians in the past have undoubtly suffered from exposure to radio waves. They were often doing their job right next to the broadcasting radio antenna, which usually was quite powerful and featured a well-focused beam. Still, the same radars have covered much of the surface of the earth and a lot of sky for decades, and I don't think there is any suspicion they might be harmful out of a very short radius around the antenna.)Comparing the situation you describe for Greece to the one we are facing in Germany, we also have a quite dramatic reduction of bird populations for many species, even the very common ones. Additionally, insect life is similarly affected. I think it's pretty clear at least for Germany, that the main driving factors behind this are habitat destruction, mostly due to intensifying land use for food production (and in the recent years, energy plants), coupled with an increase in the use of herbicides and insectides, which impacts the availability of food for many bird species.I would imagine the situation in Greece is similar in many respects, and as usual with complex problems with multiple root-causes, analysis can be very difficult. However, I wouldn't necessarily consider the radio towers to be a major contributing factor if there is no evidence of a strong localized impact in the vicinity of the towers.Just in the hope that the "bell tower" example might prove useful to you, and with the best wishes for your conservation efforts in Greece!Regards,Henning</blockquote>

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