Urban environments, also known as concrete jungles, are the most rapidly growing type of environment of the current time. They force not only the landscape, but also its inhabitants, to adapt to the completely different rules that come with living in a human-made and human-populated area. The involvement of humans has historically been a very unpredictable (and sometimes destructive) element for ecosystems to deal with. Two factors that are unique to urban environments are the presence of light and noise pollution. The first is ever more apparent through the big domes of light at the horizon blocking the view of the stars, while the second can often go unnoticed by city residents until they find themselves in a more quiet environment (like the dunes or a dense forest). Here, I wanted to look at how the Black swan (Cygnus atratus) has been affected by noise and light pollution.
The Black swan is, like the name suggests, a swan with black feathers and legs. The exceptions for the black color scheme are their bills and eyes, which are orange-red with a white band across the bill near the front. The normal size of a black swan ranges between 120 and 142 centimeters, but despite their size they are able to travel great distances and do this regularly outside of their breeding season. Their diet consists mostly of algae and weeds, with grazing grass on land being a more rare practice. Most of the world’s black swans live in Australia and New Zealand, but due to their travels they can also be found in other continents like Africa and South America. One specific population of Black swans lives in the Albert Park Lake near Melbourne in Australia, and this population of between 130 and 150 individuals has been studied quite well over the years. Two of those studies are highlighted below—one about noise pollution and the other about light pollution (Black Swan, 2024).
Noise Pollution
When talking about noise pollution, a good example of an event with a lot of it is without a doubt a Formula One race. The Australian Formula One Grand Prix of 2011 took place on a race track that was constructed around the Albert Park Lake, leading to the Black swan population experiencing noise pollution between 73 and 121 dB during the event’s first week. But when researching the reaction of the swans, only some degree of physiological intolerance—measured as an increased amount of stress hormones—could be detected. No further changes in behaviour, no mass emigration or any of the sort. The research concluded that there are two most likely reasons for the black swans not having a significant reaction to the increased amount of noise. The first options is that the noise was not disturbing enough, possibly because it was not directed at the swans or because the lake was big enough to offer more quiet refuges from the tumult. The second option was that the swans had adapted to the noise, which if true is a good example of a species adapting to the elements of an urban environment, rather than being forced to relocate (Beringen et al., 2023).
Light Pollution
It is common knowledge that looking at screens can lead to sleeping less or sleeping worse in humans, which is mainly because of the higher amount of blue light being emitted by screens. Hence why there has been a push to reduce not only the amount of blue light coming from screens, but also the amount of blue light present in urban environments. But the effect of blue light on wild animals is unknown. A 2020 study researched whether Black swans were affected more by blue-rich (white) and blue-reduced (amber) LED streetlights. Eleven swans were captured, most of which originated from Albert Park Lake, and brought to Serendip Sanctuary in Lara (Australia). In the testing location six LED streetlights were installed, after which both types of light were turned on twenty consecutive nights. As a control, the light were kept off for eighteen consecutive nights before the white light and were again kept off for nine consecutive nights between the switching from white to amber light. Afterwards, the data showed that the Black swans rested 25 minutes less with white light active and 40 minutes less with amber light active compared to the night in which the lights were kept off. But interestingly enough, no significant difference was found between the amount of sleep on white light or amber light nights, meaning that apparently the filtering out of blue light did not help the black swans with getting more sleep (Aulsebrook et al., 2020).
In conclusion, when animals, specifically black swans, are present near an urban environment they feel the effects of the noise and light pollution. And it would be wise to keep investigating the different ways in which an urban environment affects animals, because it is very clear that not all animals react the same as humans do to the anthropogenic landscape.
References
Aulsebrook, A. E., Lesku, J. A., Mulder, R. A., Goymann, W., Vyssotski, A. L., & Jones, T. M. (2020). Streetlights disrupt Night-Time sleep in urban Black Swans. Frontiers in Ecology and Evolution, 8. https://doi.org/10.3389/fevo.2020.00131
Black Swan. (2024, July 18). Australian Museum. Retrieved March 23, 2025, from https://australian.museum/learn/animals/birds/black-swan/
Payne, C. J., Jessop, T. S., Guay, P., Johnstone, M., Feore, M., & Mulder, R. A. (2012). Population, behavioural and physiological responses of an urban population of black swans to an intense annual noise event. PLoS ONE, 7(9), e45014. https://doi.org/10.1371/journal.pone.0045014
Featured photo: © Bernard Spragg
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