Ambient anthropogenic noise but not light is associated with the ecophysiology of free-living songbird nestlings

Abstract

Urbanization is associated with dramatic increases in noise and light pollution, which affect animal behaviour, physiology and fitness. However, few studies have examined these stressors simultaneously. Moreover, effects of urbanization during early-life may be detrimental but are largely unknown. In developing great tits (Parus major), a frequently-used model species, we determined important indicators of immunity and physiological condition: plasma haptoglobin (Hp) and nitric oxide (NOx) concentration. We also determined fledging mass, an indicator for current health and survival. Associations of ambient noise and light exposure with these indicators were studied. Anthropogenic noise, light and their interaction were unrelated to fledging mass. Nestlings exposed to more noise showed higher plasma levels of Hp but not of NOx. Light was unrelated to Hp and NOx and did not interact with the effect of noise on nestlings’ physiology. Increasing levels of Hp are potentially energy demanding and trade-offs could occur with life-history traits, such as survival. Effects of light pollution on nestlings of a cavity-nesting species appear to be limited. Nonetheless, our results suggest that the urban environment, through noise exposure, may entail important physiological costs for developing organisms.

Surviving in the city: higher apparent survival for urban birds but worse condition on noisy territories

“…Chronic noise is known to elevate haptoglobin immune response, which can be energetically costly (Raap et al. ), although a recent study found no correlation between decreased body size and nutritional stress (Meillère et al. ).…”

“…, Raap et al. ). Animals may also have to change their territorial behaviors in noisy urban conditions, such as approaching more closely to be able to hear an acoustic signal, which could lead to aggressive territorial interactions and potentially affect body condition, reproduction, and survival (Phillips and Derryberry ).…”

Artificial light pollution: Shifting spectral wavelengths to mitigate physiological and health consequences in a nocturnal marsupial mammal

“…However, these studies have been conducted under controlled laboratory conditions with restricted application to free‐ranging mammals. To our knowledge, only four studies have examined the effect of artificial light on oxidative status using experimental field studies on the great tit ( Parus major) (Casasole et al., ; Raap et al., ; Raap, Casasole, Pinxten, & Eens, ; Raap, Pinxten, Casasole, Dehnhard, & Eens, ) and no study has examined the impacts on a mammal under similar field conditions (Isaksson, ).…”

Cavities shield birds from effects of artificial light at night on sleep

“…There are, however, also indications that suggest that nest boxes may shield animals from direct effects of ALAN. Experimental ALAN inside a nest box affected nestling physiology (Raap, Casasole, Pinxten, & Eens, ), but ambient light pollution at the nest box was unrelated to nestling physiology (Raap, Pinxten, Casasole, Dehnhard, & Eens, ). Whether ambient light pollution leads to altered sleep behavior of birds inside nest boxes (cavities), similar to what has been found in experiments with ALAN inside a nest box using free‐living blue and great tits (Raap et al., , , ; Sun et al., ), needs to be examined.…”

“…Furthermore, during winter, our previous experiments with ALAN inside nest boxes also showed most effects to occur during the morning (Raap et al., ; ). We used a light intensity for our experimental treatment that was similar to intensities measured at nest boxes located near street lights (≤16 m; average 1.6 ± SE 0.6 lux, N = 16; Casasole et al., ; Raap et al., ), with street lights themselves often having intensities of around 10–40 lux (Gaston, Davies, Nedelec, & Holt, ). The intensity that we used may therefore be experienced by animals near street lights.…”