Impact of non-ionising radiation (NIS) on birds: legal situation, current scientific knowledge and recommendations for the protection of birds.

A new scientific review summarizes the current state of knowledge regarding the effects of electromagnetic fields (EMFs) on birds. Non-ionizing radiation (NIR) can heat and damage bird tissue, especially that of embryos and nestlings, when emitted at close range. The scientific community has confirmed this thermal effect and determined that legal protection is necessary. Of particular concern is the installation of transmitters in buildings used as nesting sites, such as church towers. Extremely low frequency electric and magnetic fields (ELF-EF/MF, 1 Hz – 100 kHz) are generated by alternating currents or pulsed direct currents. The main sources of these fields are railway networks and power grids (50 Hz). In the radiofrequency range (100 kHz – 300 GHz), electric and magnetic field components combine and propagate as electromagnetic waves. Thermal effects only occur at high field strengths. However, scientific studies have also proven the existence of non-thermal effects in birds, such as impaired magnetic orientation and oxidative stress.

Summary of the current state of knowledge:

Extremely low frequency electric and magnetic fields (ELF-EF/MF): Studies have investigated the teratogenic effects and embryonic mortality associated with these fields. Certain genotypes react more strongly to these fields, while others are insensitive. In addition to malformations, increased ornithine decarboxylase enzyme activity, oxidative stress, and heat shock protein (Hsp70) production have been observed at low field strengths close to the system limit value [1]. Biological systems react to weak EFs/MFs and EMFs, and cryptochrome proteins are discussed as possible receptors. Cryptochromes regulate physiological processes, such as circadian rhythms and oxidative balance, and play a key role in magnetic field orientation in birds.

Radiofrequency electromagnetic fields (RF-EMFs): Weak RF-EMFs up to about 100 MHz can disrupt the magnetic compass of birds; however, the impact on migratory birds remains unclear. Engels et al. (2014) demonstrated interference at conventional RF-EMFs (20 kHz –  5 MHz), and Leberecht et al. (2022) confirmed effects up to 85 MHz and 5.6 nT [2]. Theoretically, the upper limit for influence is 116 MHz. Other studies have shown increased oxidative stress in birds at around 1800 MHz or 900 MHz. The antioxidant protective mechanisms have limits, especially in young or old individuals. Molecular evidence of non-thermal effects, such as the influence of Hsp70, underscores their importance.

Field studies: Sakraoui et al. (2024) found lower survival rates in white storks nesting near mobile phone base station antennas in Algeria [3]. Balmori and other researchers found a correlation between the breeding success of white storks and house sparrows and the intensity of mobile phone base stations (900/1800 MHz) [4]. However, these studies did not consider other factors. More recently, a study found no effect on house sparrows, whose populations increased in Switzerland. Nevertheless, it is unclear whether laboratory findings can be applied to natural conditions because organisms can partially compensate for damage. Multifactorial causes, such as genetics and the environment, also play a role.

Although birds must be protected from non-ionizing radiation (NIR) according to environmental regulations, there are currently no specific regulations in place. The Swiss Ornithological Institute recommends applying the provisions of the Ordinance on the Protection Against Non-Ionizing Radiation (NISV) to birds, especially in breeding areas. Bird embryos are at risk with an increase in temperature of just 0.5°C, whereas humans can tolerate up to 1°C. These limits are too high for birds. Scientifically undisputed risks, such as thermal effects, are sometimes ignored, even by the Swiss government (www.5g-info.ch). Protecting flora and fauna requires science-based, case-by-case assessments that are updated regularly. (AT)

1. Mevissen M, Schürmann D (2021). Gibt es Hinweise auf vermehrten oxidativen Stress durch elektromagnetische Felder? Eine Zusammenfassung neuerer relevanter Tier- und Zellstudien in Bezug auf gesundheitliche Auswirkungen. Bern and Basel Universities, on behalf of Federal Office for the Environment (BAFU), Switzerland.

2. Engels S, Schneider N-L, Lefeldt N, Hein CM, Zapka M, Michalik A et al. (2014). Anthropogenic electromagnetic noise disrupts magnetic compass orientation in a migratory bird. Nature 509: 353–356. https://doi.org/10.1038/nature13290

Leberecht B, Kobylkov D, Karwinkel T, Döge S, Burnus L, Wong SY et al. (2022). Broadband 75–85 MHz radiofrequency fields disrupt magnetic compass orientation in night-migratory songbirds consistent with a flavin-based radical pair magnetoreceptor. Journal of Comparative Physiology, 208(1), 97–106. https://doi.org/10.1007/s00359-021-01537-8

3. Sakraoui D, Ziane N, Ghalem R, Boukheroufa M, Habbachi W (2023). Is there an effect of electromagnetic waves from base stations on the breeding success of Ciconia ciconia in Algeria? Biosystems Diversity, 31(4), 493–499. https://doi.org/10.15421/012358

4. Balmori A (2009). Possible effects of electromagnetic fields from phone masts on a population of white stork (Ciconia ciconia). Electromagnetic Biology and Medicine, 24(2), 109–119. https://doi.org/10.1080/15368370500205472