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Does noise or urban living affect tree sparrow growing patterns?

Noise pollution is widespread and includes traffic noise (both terrestrial, aerial, and maritime), industrial and recreative activities. There are few places free from this invisible form of pollution. Besides humans, animals also have to cope with noise, especially those that rely on acoustic signals for communication such as birds.

It is known that noise can alter bird’s behaviour ranging from frequency modification of the songs to modification of activity patterns. However, noise firstly interacts with our physiology, disrupting glucocorticoid secretion or even causing oxidative damage inside cells. Chronic exposure to stressors such as noise can ultimately compromise individual’s health.

One of the loudest and most disturbing noises is the generated by aircrafts, which can exceed 110 decibels. Birds living close to airports have been shown to shift their song timing to avoid aircraft noise and have also been found to increase their vigilance time over time spent in foraging. However, little is known about the physical and physiological state of birds being born and growing under the airport influence. In this study, we compared the body condition, corticosterone levels and oxidative status of 3 subpopulations of tree sparrow (Passer montanus) nestlings living in 3 different areas: a rural riverine zone, the same rural habitat adjacent to the Barajas airport and an urban area located in Madrid city.

Our results showed that airport nestlings did not differ from their rural counterparts neither in body condition nor in stress levels. Indeed, they showed greater levels of antioxidants. On the other hand, urban tree sparrows were in lower body condition and showed reduced antioxidant levels. The abundance and great variety of pollutants in cities along with a poorer quality diet are likely to be behind these results.

Our work suggests that exposure to multiple stressors and an impoverished habitat, like cities, contribute synergically and negatively to tree sparrow’s condition. Birds in the airport, mainly exposed to aircraft noise, did however as good as their rural counterparts. It is likely that the type of noise (gradual and predictable) and the absence of other pollutants together with an overall better diet did not compromise airport sparrow’s health. To disentangle the relationship between noise and its influence on wildlife is necessary to expand this type of study to more airports by replication and go for an experimental approach.

We hope our study serves as a motivation to puzzle out the relationship between anthropogenic landscapes and their inhabitants.



  • Tree sparrow
  • Tree sparrow discovering the world it's born to