Noise Pollution: The Enemy Of Birds

For city-dwelling birds, noise pollution can cause more than hearing loss. According to new studies, it is believed that this aspect can shorten the lives of these animals.
Noise pollution: the enemy of birds

Noise pollution is a reality in all fast-growing and expanding cities. Undoubtedly, with each new urban planning project a new headache arises, perhaps especially for the birds.

Urban planning and industrialization not only change the landscape and food sources, they also affect bird nesting and many other vital parameters.

The difficulty of studying noise pollution in birds

It is important to note that, in the real world, studying the effect of noise pollution is difficult. This is because it is necessary to distinguish which stressor is most harmful to birds among all the hustle and bustle of urban life.

Furthermore,  bird reactions to noise depend on the type of noise produced,  including frequency, volume, consistency and duration.

Some bird species react more negatively to noise than others. For example, birds that form colonies are highly susceptible to noise: when a bird reacts, its companions imitate it.

Noise pollution induces changes in reproductive success

Noise can affect egg production, hatching, rearing and flight response to nest predators. It also influences the ability to find or attract a mate and the parent’s effectiveness in listening to and responding to their pups’ pleading appeals.

Noise pollution induces changes in reproductive success

Noise can mask communication between birds

In all avian taxa, social relationships are based on sound communication. Typically, vocalization dominates much of first-order contact.

Background noise can obscure or interfere with communication or threat detection, producing what scientists call “masking”.

The importance of masking is that it makes it difficult for birds to communicate vocally in order to attract their companions, defend territories and flee from threats, as the noise can also mask calls for help and alerts.

Also, it is important to note that contact calls help maintain group cohesion. For this reason, masking can potentially result in the  loss of individuals or the breakdown of group cohesion.

To make this problem even worse, it is common for the “dawn chorus” of birds to coincide with the peak time of the heaviest traffic. For all these reasons, noise can determine habitat quality and reproductive success.

Noise pollution produces changes in song components and redundancies

According to field studies, male finches that inhabit naturally noisy areas sing some song components for longer periods than their counterparts in quieter areas. In addition, the finches produced rapid trills in shorter episodes.

The researchers suggest that these changes could be a trade-off  between attracting females with the trills and, at the same time, reducing neuromuscular fatigue.

Intense noise can induce changes in singing hours

There are reports that, in the city, nightingales manage to adjust the maximum time of their singing to avoid acoustic interference.

In other research, it was documented that the small flycatchers ( Empidonax minimus ) and the juruviaras ( Vireo olivaceus ) changed their storytelling schedule to avoid overlapping their songs.

Noise pollution seems to be an  influencing factor in the changes from daytime to nighttime singing among robins ( Erithacus rubecula ) in some cities. Interestingly, changes in song timing in frogs associated with loud noises have also been reported.

Birds under stress due to noise pollution may live less

According to a recent report, exposure to noise pollution in mandarins ( Taeniopygia guttata ) induces stress that may be related to rapid aging and shorter life expectancy.

It should be noted that scientists use the size of pieces of DNA called telomeres as an indicator of longevity. This piece of DNA forms the end of chromosomes, similar to the plastic that protects the end of a strand.

In that report, the authors found a substantial shortening in the telomeres of young birds subjected to 100 days of acoustic exposure. It is not yet known whether these birds will actually live shorter than the group that was not subjected to the noise.

Birds under stress may live less

beyond the ear

Noise pollution affects birds in a number of ways, including physical damage to the ears. It also induces changes in your stress, avoidance, and avoidance responses.

In addition, changes in their vocal communication, food-seeking behavior and reproductive success were observed. In general, all of these variations can result in reductions in exposed bird populations.

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