Hyderabad: Sound pollution hits birds and animals' ability to survive. Various studies have claimed that noise pollution has physiological and behavioral impacts on animals and birds. Some of the effects of high man-made noise levels are; breeding, foraging, and stress among wildlife. Time and again, these have been highlighted by various studies largely concentrated in Europe and North America.
“Noise can damage the nervous system of animals, increase their heart rate and stress levels,” says Dr. Khanna, who advocates reducing the use of crackers during festivals, marriages, and victory processions.
A 2014 study from the University of Exeter showed how high noise affected the survival likelihood of European eels. When eels were exposed to ship noise, they were distracted and more likely to be caught by a predator. Furthermore, some had diminished spatial performance and elevated levels of stress.
The study concluded that “acoustic disturbance could have important physiological and behavioral impacts on animals, compromising life-or-death responses.”
Road and construction noise, especially in the greener fringe urban areas, is a particular source of disturbance to wildlife. Indeed, one 2005 study from the University of Virginia showed that the breeding density of birds living near roads declined.
Some animals and birds do adapt to noisier surroundings, Kehimkar notes. “They may migrate to a more peaceful place for a while, although they will have to come back eventually if they are stray dogs or birds that survive in cities,” he said. But just because some creatures can adapt to a noisy environment doesn’t mean they’re not hurt by it.
Birds do not habituate to traffic noise. Traffic noise affects normal stress reactions in zebra finches and delays offspring growth.
In zebra finches, noise affects their health and the growth of their offspring. Researchers at the Max Planck Institute for Ornithology in Seewiesen found that traffic noise suppresses normal glucocorticoid profiles in the blood, probably to prevent negative effects of chronically elevated levels on the organism. In addition, the young chicks of noise-exposed parents were smaller than chicks from quiet nests.
Now, a research team at the Max Planck Institute for Ornithology in Seewiesen headed by Henrik Brumm has studied the effect of noise on stress hormone levels, health, and reproductive success in breeding zebra finches. Two groups of birds bred in both noise and no-noise conditions. The noise groups were exposed to traffic noise recorded at several busy intersections in and around Munich during the whole breeding period. Just as in a real city, the traffic noise varied throughout the day, with the sounds of heavier traffic during the day and lighter traffic during the night.
Sometime after the end of the first breeding period, the noise conditions changed for both groups and the same pairs bred again. The researchers recorded the level of stress hormones before, during, and after the breeding period, respectively. In addition, they took measures of the immune function, and reproductive success, as well as the growth rates of the chicks.
They found that birds in constant traffic noise had lower levels of corticosterone in their blood compared to when they were breeding in a quiet environment. This was surprising because stress often results in higher levels of corticosterone, a hormone involved in metabolism regulation during stressful experiences. “In the birds breeding in quiet environments, their baseline corticosterone remained low throughout the breeding season”, says Sue Anne Zollinger, lead author of the study.
“This suggests that the birds didn’t habituate to, or get used to the noise since their hormone levels did not track the normal ups and downs that occur during the normal breeding cycle in non-noise exposed birds. Instead, the suppression of the corticosterone levels may be a way to protect from the negative consequences of chronically elevated stress on the immune system.”
The study was done with birds in aviaries in order to exclude other factors generally associated with traffic, such as chemical pollution, light pollution, and other differences found in urban areas for example in the density and composition of the bird communities, habitat structure, changes in microclimate or food type and availability.
“Our data shows that traffic noise alone, without all the other disturbances of an urban environment, changes the physiology of birds and has consequences on their growth”, says Henrik Brumm, research group leader in Seewiesen. This means that even bird species that seem at first glance to be coping well in cities may be affected by chronic traffic noise.
Chicks whose parents were exposed to traffic noise were smaller than chicks from parents that bred in quiet aviaries. However, once the chicks from noisy conditions left the nest and could feed on their own, they managed to catch up with the chicks from quiet nests.
The researchers, however, do not exclude long-term effects on the offspring. This is because a previous study showed that traffic noise exposure accelerated telomere loss in juvenile zebra finches, which is predictive of a shorter lifespan. On the number of chicks in the nest, however, traffic noise.
Biological Experts Comments
Experts claim that different species of animals and birds rely on sounds for finding desirable habitat and mates, avoiding predators, protecting offspring, and establishing territories. However, the man-made noise pollution hampers animal communications by disrupting their crucial communication cues, claims the study.
Experts said the noise generated by activities in the city, such as vehicular movement, bursting of firecrackers, and blasting at construction sites, can create several problems for animals. They said it can lead to animals going into a state of panic, increase their blood pressure drastically, and can also interfere with the mating calls of some birds and animals.
“Loud noise can affect reproduction and even the social behavior of animals. They panic and run to escape the noise. In this process, their body releases adrenaline due to which the blood pressure shoots up drastically. This can also lead to cardiac arrest and death due to shock,” said a senior veterinary expert, associated with the forest department.
“Animals go into a state of fear when there is continuous exposure to loud noise. They hide and do not come out to socialize or mate. For some animals, the noise can drown the mating calls and other communication signals,” the expert added.
The Wildlife expert further said that exposure to loud noise can also cause loss of hearing among animals. “Long-lasting exposure to loud and sudden disruptive noise can also impact the hearing ability in many animals. Some birds and animals are extremely sensitive and susceptible to high decibel sounds. Even if it is for a short while, a sudden blast can cause real harm to the wildlife,” said Adwait Kumar, a wildlife conservationist.
According to the recent data gathered from Telangana State Pollution Control Board, in Hyderabad, all the 11 noise monitoring stations across the city recorded higher noise levels than the stipulated.
Blaring sound from loudspeakers during weddings, festivals, political processions, and the continuous honking in cities lead to noise pollution, which can result in severe health issues. But, this man-made noise pollution is not only affecting humans, but it also has adverse effects on wildlife as well, claims a study.
Meanwhile, newly published research in Global Change Biology has found that noise pollution is not just hampering human ears but also posing hurdles for animal communications. .31 species affected badly by blaring noises. The study, looked at 31 different animal species, including frogs and birds that were affected by noise pollution. The lead author of the research Dr. Hansjoerg Kunc, from the School of Biological Sciences at Queen’s University, said: “There are important implications to consider around the protection of wildlife.
This research proves that man-made noise is disrupting them from hearing and understanding each other clearly, which would have an impact on their future survival.”
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