Table 1. Consequences of acoustic masking and predictions of how these non-mutually exclusive mechanisms may impact behavior under both long and short-term noise exposure in Western Bluebirds.

Mechanism	Prediction
Increased vigilance	Because noise increases the perception of risk (Meillere, Brischoux & Angelier, 2015; Quinn et al., 2006), birds should approach the nest more slowly, spending more time within 10 m of the nest during the approach and provision less. Similarly, birds should provision less and have a longer latency to resume provisioning under continuous noise exposure.
Reduced foraging	Because increased visual vigilance in noise comes at a cost to foraging rate (Sweet et al., 2022) and noise can reduce foraging efficiency by masking prey sounds (Montgomerie & Weatherhead, 1997; Mason, McClure & Barber, 2016; Senzaki et al., 2016), there should be a decline in provisioning rate, but not necessarily time spent within 10 m of the nest box.
Missed detections	Because noise contributes to chicks failing to hear the arrival of parents (Leonard & Horn, 2012; Lucass, Eens & Müller, 2016), there should be more failed provisioning attempts with short-term experimental noise exposure and/or increased sound levels.