| Anthropogenic noise is an increasingly prevalent global disturbance. Animals that rely on the acoustical environment, such as songbirds, are especially vulnerable to these sounds. Traffic noise, in particular, overlaps with the frequency range of songbirds, inducing masking effects. Because of this, I expected anthropogenic noise exposure to interrupt parent-offspring communication and lead to potential changes in vigilance behaviors. I investigated the effects of chronic traffic noise on the breeding success of nesting western bluebirds (Sialia mexicana) and ash-throated flycatchers (Myiarchus cinerascens). I was able to eliminate any self-sorting among individuals and other possible effects of traffic, such as collisions and pollution, by experimentally introducing playback systems into nest boxes after clutch initiation. Preliminary results indicate no effect of traffic noise on S. mexicana clutch size, brood weight, or fledgling success. However, preliminary results suggest that M. cinarascens may experience fitness consequences from chronic anthropogenic noise exposure. I contrast responses by these two species in light of recent observational work on both species in New Mexico and other studies that have examined fitness consequences of noise.
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