Noise and light pollution have mixed effects on bird reproduction, reports a paper in Nature. The findings, based on data from a citizen science project across the United States, suggest that noise and light pollution need to be considered alongside other environmental factors in conservation efforts.
Noise and light from human activity is becoming an increasing conservation concern. Previous studies have identified physiological and behavioural responses to these stimuli but how they affect reproductive success, and how effects might vary in different species is not well understood.
Clinton Francis and colleagues examined the influence of noise and light pollution on 142 bird species in the United States, using data collected from 58,506 nests between 2000 and 2014 by a citizen science project. They examined the date of first egg-laying, clutch size, partial hatching success, clutch failure and nest success, which they combined with geospatial data on anthropogenic noise and light pollution. The authors found that birds exposed to more light began laying eggs around three or four weeks earlier than those exposed to less light. They also found that birds that prefer closed habitats, such as forests, produced clutches approximately 16% larger in well-lit versus darker areas. Birds in closed habitats experienced a decline in clutch size with noise exposure, but this effect was not observed in birds from open habitats such as grasslands and wetlands.
The authors conclude that human-generated noise and light can impact bird breeding and fitness with closed habitat birds showing greater sensitivity to noise and light than those in open habitats, underscoring the need to consider these pollutants when implementing biodiversity conservation.
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