I would say wind turbines and solar farms are far more a threat to the bird population than cell towers. The reflective surface of solar panels can reflect and concentrate the sun's energy to strike birds in mid-flight and wind turbines can slice and dice birds. You know, when wind turbines are actually getting wind to operate. In the California desert they tend to be more for decoration.
The standard practice of radio engineering is to only use the amount of power necessary to send communications. Cell towers generally put out less energy than television and radio station towers. Also, even though the frequencies are within the microwave band the electromagnetic radiation from cell towers is non-ionizing so it can't cause damage to DNA. The worst the EM from a cell tower can do is vibrate the water molecules in cells which can cause RF burning if you actually touched the antenna while it is transmitting.
The amount of cell tower radiation people normally get at ground level is negligible. Birds may get slightly more exposure because the tower's energy is directed parallel to the ground. Even then due to the inverse-square law that extra exposure is still negligible.
Do we kill our furry friend with radiation? This question may sound artificial, but it's not really a broad imagination. Microwaves do cause warming and other changes that are more subtle in biological tissue.
Beside birds, bees get sick and disorientated, and the entire nest is abandoned - we even have a new name for the phenomenon: Colony Collapse Disorder or Vanishing Bee Syndrome. Mysterious diseases have destroyed most honeybee populations in several countries. There are several links to pesticides, genetically modified crops that produce poisons are a hypothesis, but microwave radiation as used in communication equipment is also involved. In the case of documented honeycomb disappearances in Germany a few years ago, bees disappeared from nests exposed to microwaves from nearby mobile relay towers, while other nests, located behind the protection of aluminum plates, remained in the place.
Apart from birds that are disoriented and dead in the cellphone tower environment, is it possible that radiation is responsible for the persistence of what we call bird flu? This disease has killed chickens and other poultry and is officially attributed to the common virus by marking H5N1.
Avian viruses make sense due to accidents due to ignorance, or neglect, of the cumulative effects of exposure to electromagnetic radiation, especially microwaves, which continue to increase and coincide with the practice of high tech and modern chicken production systems.
Comprehensive monitoring and recording of background radiation in geostatic patterns of vital locations especially in areas that are densely populated with animal husbandry and human populations.
the implementation of the WHO 'Prevention Principle' as the National Standard for further efforts in electromagnetic applications.
Ensure public access to radiation hazard information.