Rapid population growth and the urbanization of modern environments are
markedly increasing human-wildlife conflict. Wild animals in urban landscapes
can benefit from exploiting human resources, but are also exposed to
increased risk of human-caused injury, which should favor the ability to
perceive and respond to human cues. ...
Rapid population growth and the urbanization of modern environments are
markedly increasing human-wildlife conflict. Wild animals in urban landscapes
can benefit from exploiting human resources, but are also exposed to
increased risk of human-caused injury, which should favor the ability to
perceive and respond to human cues. Although it is well known that
domesticated animals use human cues that may indicate threats, less is
known about wild animals living in urban environments. Herring gulls (Larus
argentatus) in urban landscapes have adapted kleptoparasitic behaviors to
obtain human food, often resulting in negative interactions with humans.
Here we quantified both the behavioral and physiological responses of freeliving urban herring gulls to human shouting. We presented urban gulls
with a fake human food item and played back recordings of either a
man shouting, a natural stressor (i.e., conspecific alarm call), or a neutral
stimulus (i.e., robin song). We recorded behavioral responses and used noninvasive infrared thermography to measure eye-region surface temperature
changes associated with the avian physiological stress response. We found
that gulls exposed to shouting and to conspecific alarm calls showed similar
changes in behavior (indicating high levels of vigilance) and eye-region
surface temperature (indicating physiological stress). Both responses were
significantly stronger than the responses to robin song. Additionally, the
behavioral and physiological responses were positively correlated across
individuals. Our results demonstrate that urban-dwelling gulls respond to
human shouting and conspecific alarm calls in a similar way, and suggest that
infrared thermography is a viable technique to monitor stress responses in
free-living birds.