Short-term exposure to unmanned aerial vehicles does not alter stress responses in breeding tree swallows.

Recent studies suggest that visual and acoustic anthropogenic disturbances can cause physiological stress in animals. Human-induced stress may be particularly problematic for birds as new technologies, such as drones, increasingly invade their low-altitude air space. Although professional and recreational drone usage is increasing rapidly, there is little information on how drones affect avian behavior and physiology.

The effects of anthropogenic noise on feeding behaviour in black-capped chickadees (Poecile atricapillus).

Anthropogenic noise has been shown to impact animal behaviour. Most studies investigating anthropogenic noise, and the detrimental effect it has on behaviour, have been conducted in the field, where a myriad of covariates can make interpretation challenging. In this experiment, we studied the effects of an approximation of anthropogenic noise, simulated with brown noise, on the feeding behaviour of wild-caught black-capped chickadees in a laboratory setting.

Hearing is believing: Birds learn fear.

Although it is known that animals attend to the vocalizations of others (referred to as eavesdropping), what has been missing, or at least left experimentally unproven, until now is whether animals can learn new associations between a signal and a threat. Here Magrath and colleagues (Current Biology, 25(15), 2047-2050, 2015) have for the first time conducted a field experiment that demonstrates just this: superb fairy-wrens learned to associate a novel vocalization with a predator.

Anthropogenic noise decreases urban songbird diversity and may contribute to homogenization.

More humans reside in urban areas than at any other time in history. Protected urban green spaces and transportation greenbelts support many species, but diversity in these areas is generally lower than in undeveloped landscapes. Habitat degradation and fragmentation contribute to lowered diversity and urban homogenization, but less is known about the role of anthropogenic noise.

Flexibility in animal signals facilitates adaptation to rapidly changing environments.

Charles Darwin posited that secondary sexual characteristics result from competition to attract mates. In male songbirds, specialized vocalizations represent secondary sexual characteristics of particular importance because females prefer songs at specific frequencies, amplitudes, and duration. For birds living in human-dominated landscapes, historic selection for song characteristics that convey fitness may compete with novel selective pressures from anthropogenic noise.

The effect of schedules of reinforcement on the composition of spontaneous and evoked black-capped chickadee calls.

Songbirds often modify elements of their songs or calls in particular social situations (e.g. song matching, flock convergence, etc.