The rapid growth of commercial and military aviation across cities has resulted in large-scale air traffic (Barber et al., 2010). As birds dwelling in urban areas and even protected areas become increasingly exposed to these extreme levels of anthropogenic noise, they are forced to adapt to their new acoustic environments, influencing their behaviour, occupancy of existing habitats, and population numbers (Francis et al., 2011; Schroeder et al., 2012). 

A study conducted in Europe reveals how particular species of city birds living near airports resort to alternative ways of maintaining and increasing communication amidst loud periods of aircraft noise (Gil et al., 2015). One prominent way is through the shifting of song activity schedules so as to avoid coinciding with noise from aircraft traffic (Gil et al., 2015). For example, European blackbirds were observed to begin their morning chorus based on traffic noise levels (Nordt and Klenke, 2013). The results showed that bird communities living nearer the major Madrid airport advanced their dawn singing times, with those whose singing time coincided the most with aircraft noise displaying the greatest shifts in song timing (Gil et al., 2015). 

In the United States, a study highlighted how birds living across 48 national parks produced more vocalisations (Vyawahare, 2019), singing louder and more frequently in the presence of aircraft noises (Kobilinsky, 2020).

As birds rely on these songs to assert their territories or attract potential mates, these behavioural changes that move away from ideal singing times, frequencies and amplitudes could incur higher energetic and foraging costs, affecting reproductive rates, especially during breeding seasons (Gil et al., 2015). For instance, brent geese that are interrupted by aircraft noises every half an hour took 30% more time to feed (Vyawhere, 2019). 

Aircrafts could also be viewed as “looming predators” to escape and seek shelter from, potentially increasing the stress levels of birds and diminishing their ability to protect their territories (Vyawahare, 2019). Furthermore, the loud engines of airplanes can cause hearing impairment amongst bird populations. For instance, Chiffchaffs living near Manchester Airport in England displayed signs of hearing loss in relation to airplane take-offs (Vyawhere, 2019). 

Moving forward, it is important for wildlife researchers and conservationists to further examine the types of bird species that are most vulnerable to air traffic and design protected, wildlife areas that consider the wide-spreading nature of aircraft noise (Kobilinsky, 2020). 

 

References: 

Barber, J.R., Crooks, K.R. & Fristrup, K.M. (2010). The costs of chronic noise exposure for terrestrial organisms. Trends Ecol. Evol. 25: 180–189.

Francis, C.D., Ortega, C.P. & Cruz, A. (2011). Noise pollution filters bird communities based on vocal frequency. PLoS One. 6: e27052.

Gil, D., Honarmand, M., Pascual, J., Pérez-Mena, E., & Macías Garcia, C. (2015). Birds living near airports advance their dawn chorus and reduce overlap with aircraft noise. Behavioral Ecology, 26(2), 435-443.

Kobilinsky, D. (2020). Birds sound off when aircraft fly by. Retrieved 4 March 2022, from https://wildlife.org/birds-sound-off-when-aircraft-fly-by/

Nordt, A. & Klenke, R. (2013). Sleepless in town: drivers of the temporal shift in dawn song in urban European blackbirds. PLoS One. 8:e71476.

Schroeder, J., Nakagawa, S., Cleasby, I.R. & Burke, T. (2012). Passerine birds breeding under chronic noise experience reduced fitness. PLoS One. 7: e39200.

Vyawahare, M., (2019). Do birds try to shout down airplanes? The evidence suggests they do. Retrieved 4 March 2022, from https://news.mongabay.com/2019/12/do-birds-try-to-shout-down-airplanes-the-evidence-suggests-they-do/