Did you ever wonder how noise might affect birds and their populations? Scientists have conducted studies that have demonstrated that

  • birds are significantly affected by noise, including while trying either to attract mates via song, establish nests, or listen for predators, and that
  • noise pollution can increase birds’ stress levels and reduce their sizes and life spans.

The citizen-scientist program FeederWatch analysed data from more than 3.4 million observations of 140 different bird species across North America. They found that most species, including common birds such as goldfinches, cedar waxwings, and white-breasted nuthatches, avoided areas of excessive noise. They even avoided backyard feeders in these areas, indicating the widespread nature of this effect. Another study, using data for reproductive success from the citizen-science NestWatch program, including 58,506 nests from 142 species of birds, showed that human noise pollution delayed nesting for birds with songs having a lower frequency. Lower-frequency songs are more difficult to hear with background noise, thus delaying mate attraction. Birds singing at higher frequencies were less affected. Also, forest birds were more affected than birds in open environments.

A study conducted in Munich, Germany examined the breeding success of zebra finches exposed to traffic noise in Munich. Chicks born in the noisiest places were smaller than those from parents who bred without noise. Fortunately, these chicks were able to catch up in size with chicks from quiet nests once they left the noisy nest to forage on their own. Unexpectedly, young birds exposed to constant traffic noise in their earliest days had lower signs of stress as indicated by lower levels of the hormone corticosterone in their blood compared to those hatched in quiet environments. This may be a way for the birds to avoid the damage to their immune systems, increased anxiety, inflammation, and disease susceptibility that chronic exposure to stress hormones can cause. Apparently, maintaining low corticosterone levels while exposed to noise is the body’s way of coping with stress so intense that it must “shut down” the stress hormones in order to protect itself. The blood samples of fledged adolescents also showed changes in their chromosomes that are associated with reduction in life span. Adolescence in birds is a crucial time for learning how to communicate with each other, which is more difficult in a noisy environment, and the associated stress affected their chromosomes. This chromosomal finding has also been reported in other studies with nesting songbirds (house sparrows and great tits).

Another large study was conducted in a woodland and shrub grassland setting in New Mexico in an area with extensive gas and oil extraction equipment. These scientists placed 240 nesting boxes at increasing distances from either wells or control sites to obtain a range of noise levels and frequencies and to attract several species of native birds, including western and mountain bluebirds, and ash-throated flycatchers. Their results confirmed the findings described above for low corticosterone levels in response to increased noise levels, which were associated with reduced fitness such as smaller body size and feather growth, and lower hatching success (for Western bluebirds). Additionally, birds under chronic stress showed higher stress hormone levels compared to those in quiet environments when both populations were exposed to sudden, acute stresses. These phenomena have been observed in other species as well as birds.

Collectively these observations confirm that noise can have negative effects on the health and reproductive success of birds. While it may be challenging to eliminate or reduce human-produced noise, there are several ideas to consider, such as:

  • using electric or human-powered lawn equipment rather than gas powered, such as raking leaves instead of using a leaf blower,
  • keeping music volumes at outdoor parties and festivals at a modest level (which is better for human ears, too),
  • encouraging your community to set aside one day a week not to mow,
  • coordinating your community for weekly garbage collection by a single provider to reduce the number of pick-ups,
  • limiting the use of fireworks to special holidays such as July 4.

 

 

What are your ideas to help create quieter neighborhoods and towns?

Less noise is less stressful and good for people too!

 

John W. Shiver, Doylestown Township’s Bird Town Committee Member

Image Credit:  Main_park,_Celebration,_Florida,_USA, by Bobak Ha’Eri,  licensed under CC By-SA 2.5 Deed

References:

Dorrado-Correa et al., “Timing Matters: Traffic Noise Accelerates Telomere Loss Rate Differently Across Developmental Stages,” Frontiers in Zoology, 15:20 (2018).

Francis et al., “Noise Pollution Changes Avian Communities and Species Interactions,” Curr. Biol., 19:1415-19 (2009).

Francis et al., “Noise Pollution Filters Bird Communities Based on Vocal Frequency,” PLOSone, 6: e27052 (2011).

Kleist et al., “Chronic Anthropogenic Noise Disrupts Glucocorticoid Signaling and has Multiple Effects on Fitness in an Avian Community,” PNAS, E468-E567 (2018).

Senzaki et al., “Direct and Indirect Effects of Noise Pollution Alter Biological Communities in and near Noise-Exposed Environments,” Proc. R. Soc. B, 287, 20200176 (2020).

Zollinger et al., “Traffic Noise Exposure Depresses Plasma Corticosterone and Delays Offspring Growth in Breeding Zebra Finches,” Conserv. Phys., 7: 10.1093 (2019).