JUNE 2007

Where did all the
 sparrows go?

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

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This article can be found on the I-SIS website at 
http://www.i-sis.org.uk/
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