Anthropogenic noise alters parental behavior and nestling developmental patterns, but not fledging condition

Abstract

Anthropogenic noise is a ubiquitous feature of the American landscape, and is a known stressor for many bird species, leading to negative effects in behavior, physiology, reproduction, and ultimately fitness. While a number of studies have examined how anthropogenic noise affects avian fitness, there are few that simultaneously examine how anthropogenic noise impacts the relationship between parental care behavior and nestling fitness. We conducted Brownian noise playbacks for 6 h a day during the nesting cycle on Eastern Bluebird (Sialia sialis) nest boxes to investigate if experimentally elevated noise affected parental care behavior, nestling body conditions, and nestling stress indices. We documented nest attendance by adult females using radio frequency identification (RFID), and we assessed nestling stress by measuring baseline corticosterone levels and telomere lengths. Based on the RFID data collected during individual brood cycles, adult bluebirds exposed to noise had significantly higher feeding rates earlier in the brood cycle than adults in the control group, but reduced feeding rates later in the cycle. Nestlings exposed to noise had higher body conditions than the control nestlings at 11 days of age, but conditions equalized between treatments by day 14. We found no differences in nestling baseline corticosterone levels or nestling telomere lengths between the two treatment groups. Our results revealed that noise altered adult behavior, which corresponded with altered nestling body condition. However, the absence of indicators of longer-term effects of noise on offspring suggests adult behavior may have been a short-term response.

An experimental test of chronic traffic noise exposure on parental behaviour and reproduction in zebra finches

“…Observations in other birds are similar to the findings we reported here: in white-crowned sparrows, for example, paternal nest attendance and feeding rate were found to be higher for nests closer to a road ( Crino et al, 2011 ). Since our setting allowed us to exclude confounding factors like food availability and parental quality, the combined results from our study and other field studies ( Injaian et al, 2018b ; Pandit et al, 2021 ) support that traffic noise affects parents and that increased feeding rates could be one way to mitigate negative effects of noise. However, we do not know whether zebra finches can compensate the negative effects of noise in the long-term, or how such behaviour would affect the parents.…”

“…These results are in line with the parental compensation hypothesis that posits that parents may flexibly adjust their parental care to more demanding circumstances and thus buffering negative environmental impacts ( Rehling et al, 2012 ; Vitousek et al, 2017 ). Increased nest attendance (and feeding rate) may have compensated direct negative effects (see also Pandit et al, 2021 for a similar result in bluebirds). Leonard et al (2015) also found that insect-eating tree swallow parents fed their chicks more often with elevated noise levels, although this appeared not sufficient to prevent a detrimental impact of noise on offspring body condition in this species ( Injaian et al, 2018c ).…”

“…These observed physiological and behavioural effects of noise exposure, surprisingly, are not associated with a clear pattern of knock-on effects on reproductive outcomes across studies (neither within nor between species). As listed in Table 1 , some studies reported negative effects of noise exposure on clutch size ( Injaian et al, 2018b ), hatching and fledging success ( Mulholland et al, 2018 ) and offspring body condition ( Injaian et al, 2018a , b , c ; Ferraro et al, 2020 ), while others reported an absence of effects ( Meillère et al, 2015b ; Angelier et al, 2016 ; Halfwerk et al, 2016 ; Injaian et al, 2019 ; Williams et al, 2021 ) or even mixed effects ( Ferraro et al, 2020 ; Pandit et al, 2021 ) for some of the same measurements. The overall picture suggests a slew of physiological and behavioural parameters to change if birds are exposed to anthropogenic noise, but rarely, if ever, an effect on the net outcome of reproduction during the experimental period.…”

Cognition mediates response to anthropogenic noise in wild Western Australian magpies (Gmynorhina tibicen dorsalis)

“…Focal birds in our study spent significantly more time vigilant during loud anthropogenic noise conditions, suggesting they may be trading off foraging with vigilance under these conditions. Such a trade‐off can potentially reduce body condition and provisioning rates to young during breeding (Cresswell, 2008; Kern & Radford, 2016; Pandit et al, 2021), with negative consequences for reproductive success, and population viability in the long‐term.…”

An experimental test of chronic traffic noise exposure on parental behaviour and reproduction in zebra finches

“…These observed physiological and behavioural effects of noise exposure, surprisingly, are not associated with a clear pattern of knock-on effects on reproductive outcomes across studies (neither within nor between species). As listed in Table 1, some studies reported negative effects of noise exposure on clutch size (Injaian et al, 2018b), hatching and fledging success (Mulholland et al, 2018) and offspring body condition (Injaian et al, 2018a,b,c; Ferraro et al, 2020), while others reported an absence of effects (Meilleŕe et al, 2015b; Angelier et al, 2016; Halfwerk et al, 2016; Injaian et al, 2019; Williams et al, 2021) or even mixed effects (Ferraro et al, 2020; Pandit et al, 2021) for some of the same measurements. The overall picture suggests a slew of physiological and behavioural parameters to change if birds are exposed to anthropogenic noise, but rarely, if ever, an effect on the net outcome of reproduction during the experimental period.…”