Negative impact of traffic noise on avian reproductive success

Abstract

Summary 1.Traffic affects large areas of natural habitat worldwide. As a result, the acoustic signals used by birds and other animals are increasingly masked by traffic noise. Masking of signals important to territory defence and mate attraction may have a negative impact on reproductive success. Depending on the overlap in space, time and frequency between noise and vocalizations, such impact may ultimately exclude species from suitable breeding habitat. However a direct impact of traffic noise on reproductive success has not previously been reported. 2. We monitored traffic noise and avian vocal activity during the breeding season alongside a busy Dutch motorway. We measured variation in space, time and spectrum of noise and tested for negative effects on avian reproductive success using long-term breeding data on great tits Parus major. 3. Noise levels decreased with distance from the motorway, but we also found substantial spatial variation independent of distance. Noise also varied temporally with March being noisier than April, and the daytime being noisier than night-time. Furthermore, weekdays were clearly noisier than weekends. Importantly, traffic noise overlapped in time as well as acoustic frequency with avian vocalization behaviour over a large area. 4. Traffic noise had a negative effect on reproductive success with females laying smaller clutches in noisier areas. Variation in traffic noise in the frequency band that overlaps most with the lower frequency part of great tit song best explained the observed variation. 5. Additionally, noise levels recorded in April had a negative effect on the number of fledglings, independent of clutch size, and explained the observed variation better than noise levels recorded in March. 6. Synthesis and applications. We found that breeding under noisy conditions can carry a cost, even for species common in urban areas. Such costs should be taken into account when protecting threatened species, and we argue that knowledge of the spatial, temporal and spectral overlap between noise and species-specific acoustic behaviour will be important for effective noise management. We provide some cost-effective mitigation measures such as traffic speed reduction or closing of roads during the breeding season.

A phantom road experiment reveals traffic noise is an invisible source of habitat degradation

“…Observational studies of birds near roads implicate traffic noise as a primary driver of these declines (3). Road ecology research has also shown negative correlations between traffic noise levels and songbird reproduction (4,5). Birds that produce low frequency songs, likely masked by traffic noise, show the strongest avoidance of roads (6).…”

“…In addition, although these studies implicate noise as a causal factor in population declines, many individuals remain despite noise exposure (3), but at what cost? Proposed causes of decreased fitness for birds in noise include song masking, interference with mate evaluation, nonrandom distribution of territorial individuals, disruption of parentchick communication, reduced foraging opportunities, and/or alterations in the foraging/vigilance trade-off (3,4).…”

Anthropogenic noise is associated with changes in acoustic but not visual signals in red-winged blackbirds

“…This is a subject that has started to be studied in a few bird species (Mockford and Marshall 2009;Ripmeester et al 2010;Halfwerk et al 2011b), but much more research is necessary to establish whether or not noise induced shifts in vocalization (and in other channels of communication) confer benefits and costs (Read et al 2014) to animals in terms of, for example, communication efficacy, sexual selection, and reproduction.…”

“…These and other noise-related changes in acoustic signals may improve the efficacy of communication in noise (Lohr et al 2003;Halfwerk et al 2011b;Pohl et al 2012Pohl et al , 2013. Because most energy of urban noise is found at low frequencies, an increase in song frequencies may reduce noise masking.…”

Vibratory noise in anthropogenic habitats and its effect on prey detection in a web-building spider

“…Anthropogenic noise sources such as automobile traffic and construction create low-frequency substrate-borne vibrations that may overlap with frequencies commonly used by arthropods, and may propagate with only moderate attenuation (for example, the 16e250 Hz vibrations from underground rail systems; Kurzweil, 1979). Impacts of such noises may parallel those of acoustic noises such as traffic, wind turbines, shipping and seismic exploration (Hildebrand, 2009), which influence vocalization (Di Iorio & Clark, 2010;Lampe, Reinhold, & Schmoll, 2013;Lampe, Schmoll, Franzke, & Reinhold, 2012;Slabbekoorn & Peet, 2003), antipredator (Rabin, Coss, & Owings, 2006), foraging (Croll, Clark, Calambokidis, Ellison, & Tershy, 2001;Leonard & Horn, 2012;Schaub, Ostwald, & Siemers, 2008) and reproductive behaviours (Bee & Swanson, 2007;Halfwerk, Holleman, Lessells, & Slabbekoorn, 2011). …”