Experimental anthropogenic noise impacts avian parental behaviour, nestling growth and nestling oxidative stress

Human-produced noise, from transport, urbanization and industry, is widespread. Studies of noise pollution show a wide range of effects on birds, such as alterations in communication, parental behaviour, physiology and reproductive success. These human-induced changes are likely to have long-term impacts, such as altered nestling physiology and survival, as well as reduced local population size. Further experimental field studies that simultaneously investigate the effects of noise exposure on avian behaviour, physiology and reproductive success are needed. Here, we used an experimental field study to investigate impacts of short-term traffic noise exposure on parental behaviour (i.e. vigilance and feeding rate), nestling body size and oxidative stress (as measured by oxidative status) and nestling fledging success in tree swallows, Tachycineta bicolor. Our results show negative consequences of traffic noise exposure, despite a relatively modest playback regime (6 h, every other day). Adults in noise-exposed territories were less vigilant earlier in the nestling period and fed at a higher rate later in the nestling period, compared to controls. However, increased feeding rate in noise-exposed nests did not compensate for noise impacts on nestlings: noise-exposed nestlings were smaller and had higher oxidative status, compared to control nestlings. Noise-exposed nestlings took longer to fledge, but we found no effect of noise on fledging success. These results highlight the potential long-term consequences of short-term noise exposure (decreased nestling size and increased oxidative status) and add to a growing body of literature, showing that noise pollution can negatively impact birds through both direct and indirect pathways.