Behavioral responses of crows to anthropogenic cues for food (Experiment 1 & 2)

Behavioral flexibility and the ability to respond appropriately to
anthropogenic cues that signal potential threats or rewards may promote
success of wild animals in the urban environment. Here, we examine the
behavioral responses to anthropogenic cues of free-living American crows
(Corvus brachyrhynchos), an opportunistic scavenger and common urban
exploiter. Specifically, we tested the hypotheses that crows would more
readily approach (1) novel objects and anthropogenic food when in close
proximity to trash cans, and (2) paper bags with hidden food rewards when
closer to a McDonald’s restaurant, due to their associations of food with
these cues. In addition, we examined the preference of crows for bags
marked with a McDonald’s logo versus unmarked bags, hypothesizing that
crows closer to McDonald’s would be more likely to approach the labeled
bag because of its familiarity. Consistent with our expectations, crows
exhibited a lower approach latency to anthropogenic food and novel objects
in close proximity to trash cans. Likewise, they were more likely to
approach paper bags when in proximity to a McDonald’s restaurant, but they
showed no preference for bags with a McDonald’s logo. Overall, we found
evidence that the foraging behavior of crows varied in the presence of
specific anthropogenic cues and that these responses depended on their
probable cue familiarity. Their ability to use anthropogenic cues specific
to the local environment, combined with their exploitation of human food
resources, likely contributes to the success of the American crow in the
city.