Science in Society Archive

Mobile Phones & Vanishing Birds

Birds near mobile phone base stations do not breed well Dr. Mae-Wan Ho

Where did all the sparrows go?

The sparrows have disappeared completely from the cities at least four years ago in Britain, as mobile phones grew in popularity. Third generation (3G) mobile phones were introduced in 2003, and there were over 65 million users in the UK by the end of 2005, more phones than people [1]. Did mobile phone transmitters cause the sparrows to disappear [2]?

Scientists at the Research Institute for Nature and Forests in Brussels, Belgium, have produced the first evidence that mobile phone base stations are affecting the reproductive behaviour of wild sparrows [3]. This finding comes as mobile phones are held suspect in the massive collapse of bee colonies all over the United States and Europe [4] ( Mobile Phones and Vanishing Bees , SiS 34).

Joris Everaert and Dirk Bauwens wanted to know if the low intensity microwave radiation from mobile phone base stations has any effect on the number of house sparrows during the breeding season. They identified 150 locations distributed over six residential districts in Gent, Sint and Niklaas in the province of East Flanders, where they counted the number of male house sparrows and measured the strength of electromagnetic radiation from base stations.

The study areas were similar, with abundant hedges, bushes, and other vegetation between the houses, and one or more GSM (Global System for Mobile Communications) base stations nearby. All locations were along small roads within the residential areas and at variable distances from the nearest GSM (mean 352 m, range 91-903 m, about 90 percent at 100-600 m). On days when the weather was favourable, so male sparrows would be out singing, the researchers went to each location between 7 and 11 am, and using binoculars, counted the number of male sparrows within a radius of about 30 m for a period of five minutes.

Simultaneously, they measured the maximum value of the electric field strength (in V/m) from the GSM 900 MHz and GSM 1800 MHz base station antennas during 2 minutes for each frequency band, using a portable calibrated high-frequency spectrum analyser.

Everaert and Bauwens found that the number of house sparrow males varied between zero and four at the different locations. The measured electric field strengths were seldom higher than 1V/m, and most often well below that value. Nevertheless, the spatial variation in the number of house sparrow males was negatively and highly significantly correlated to the strength of electric fields from both the 900 and 1800 MHz frequency bands and from the sum of these bands. This negative correlation was very similar within each of the six districts, despite differences in both the number of birds and radiation levels.

Fewer house sparrow males were seen at locations within relatively high electric field strengths of GSM base stations. For example, the mean number of male sparrows varied from 1.9 at the combined field intensity of 0.13 V/m to 0.8 at a combined field intensity of 0.247 V/m.

The results, though preliminary, do support the hypothesis that long-term exposure to higher levels of radiation negatively affects the abundance or behaviour of house sparrows in the wild. Fewer males singing would mean less breeding success.

White storks breeding success plummets near mobile phone transmitters

Sparrows are not the only wild birds affected. Phone masts were found to actually reduce the breeding success of white storks in Spain.

Alfonso Balmori, a conservation biologist in Valladolid, Spain, reported a significantly lower number of white stork ( Ciconia ciconia ) fledglings in nests close to mobile phone transmitters compared to nests further away [5].

To monitor the breeding success of the white stork population, 60 nests were selected and visited from May to June of 2003. The selected nests had similar characteristics. They were located on the roof of churches and buildings inside urban centres in Valladolid. As the cell phone transmitters are everywhere, very few places had zero background intensity. So nests were chosen that were exposed at very high or very low levels of EMR, depending on the distance from the nests to the antennas.

Thirty nests were located within 200 m of one or several antennae (GSM-900 MHz and DCS-1800 MHz) placed on masts and on the roof of the buildings at a height of 15-30 m. Another 30 chosen were located further than 300 m from any transmitter. The nests were observed with telescopes and the number of young counted. The electric field intensity in V/m was measured.

The average number of fledgling produced per nest in nests located within 200 m of phone antennae was 0.86 + 0.16. For nests located further than 300 m, the number was 1.6 + 0.14. Twelve nests (40 percent) close to the antennae were without young, as opposed to one nest (3.3 percent) among those further than 300 m.

The mean electric field of nests within 200 m was 2.36 + 0.82V/m compared to 0.53 + 0.82V/m for nests further than 300 m.

Balmori also found difference in how the birds behaved close to the phone antennae. Young birds died from unknown causes, and bird couples frequently fought while constructing their nests. Sticks fell to the ground, and the couple failed to make any headway. Some nests were never completed and the storks remained passively in front of the antennae.

Laboratory studies show bird embryos die when exposed to microwaves

The observations in urban sparrows and the white stork population suggest that microwave radiation interferes with reproductive behaviour and breeding success, which would have decimated the wild populations. But that's not the whole story.

Several million birds of 230 species die each year from collisions with telecommunications masts in the United States during migration [6]. Accidents happen mainly in the night, in fog, or bad weather, when birds might be using the earth's magnetic field for navigation, and could be seriously disoriented by the microwave radiation from telecommunication masts.

In the UK, where the allowed radiation level is 20 times higher than in Spain, a decline of several species of urban birds has occurred [2], coinciding with the increasing installation of mobile phone masts.

Birds are good candidates as biological indicators for low-intensity electromagnetic radiation (EMR); they have thin skulls, their feathers can act as dielectric receptors of microwave radiation, many species use magnetic navigation, they are very mobile and possible psychosomatic effects are absent, as Everaert and Bauwens [3] point out.

Another important factor is that chicken embryos subjected to the radiation from a cell phone in the laboratory suffered much higher mortalities than non-exposed controls. Some years ago researchers in Russia showed that continuous exposure of the chick embryos during the 21 days of embryonic development resulted in 75 percent of the embryos dying, compared with 16 percent in the controls [7].

Article first published 29/05/07


  1. History of cellular mobile communications. Mobile Operators Association,
  2. Raven JU, Nobel DG and Baillie SR. The breeding bird survey 2002. BTO Research Report 334, British Trust for Ornithology, Thetford, 2003.
  3. Everaert J and Bauwens D. A possible effect of electromagnetic radiation from mobile phone base stations on the number of breeding house sparrows ( Passer domesticus ). Electromagnetic Biology and Medicine 2007, 26, 63-72.
  4. Ho MW. Mobile phones and vanishing bees. Science in Society 34 (in press).
  5. Balmori A. Possible effects of electromagnetic fields from phone masts on a population of White Stork ( Ciconia ciconia ). Electromag. Biol. Med. 2005, 24:109–119.
  6. Shire GG. Brown K, Winegrad G. Communication towers. A deadly hazard to birds. American Bird Conservancy, 2000.
  7. Grigor'ev IuG. Biological effects of mobile phone electromagnetic field on chick embryo (risk assessment using the mortality rate. Radiat. Biol Radioecol. 2003, 43, 541-3. (in Russian).

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