Chronic traffic noise is increasingly recognised as a potential hazard to wildlife. Several songbird species have been shown to breed poorly in traffic noise exposed habitats. However, identifying whether noise is causal in this requires experimental approaches. We tested whether experimental exposure to chronic traffic noise affected parental behaviour and reproductive success in zebra finches (Taeniopygia guttata). In a counterbalanced repeated-measures design, breeding pairs were exposed to continuous playback of one of two types of highway noise previously shown to be either neutral (control) or aversive. Parental nest attendance positively correlated with feeding effort and was higher for the aversive than the control sound and this effect was more pronounced for parents attending larger broods. However, neither noise condition affected offspring number, growth or body mass. The absence of an effect held when we combined our data with data from two other comparable studies into a meta-analysis. We discuss whether the increased nest attendance could be a compensatory strategy that alleviated detrimental noise effects on the chicks, and whether it could be caused by impaired parent-offspring or within-pair communication. Future work should test these hypotheses and investigate potential long-term costs of increased parental engagement.

Chronic traffic noise is increasingly recognised as a potential hazard to wildlife. Various songbird species, for example, have been shown to breed poorly in traffic noise exposed habitats. However, identifying whether noise is causal in this requires experimental approaches. We here tested whether experimental exposure to chronic traffic noise affected parental behaviour and reproductive success in offspring number and growth in an important model of avian development, the zebra finch (Taeniopygia guttata). In a counterbalanced repeated-measures design, breeding pairs experienced continuous playbacks of one of two types of highway noise that previous spatial choice tests had shown to be neutral (control) or aversive. We monitored offspring development and parental feeding rates and nest attendance. Parental nest attendance was positively correlated with feeding effort and was higher in the aversive than in the control sound treatment and this effect was more pronounced for parents attending larger broods. However, neither noise condition affected offspring number, growth or body mass. There was also an absence of an effect of noisy conditions on these reproductive parameters when we combined our data with two other comparable studies in the same species in a meta-analysis. We discuss whether the increased parental engagement is a potential compensatory strategy that alleviated direct noise effects on the chicks. However, impaired parent-offspring or within-pair communication could also have increased parents’ nest attendance time. Future work is required to test these possible explanations and investigate potential long-term costs of increased parental engagement.