Neophobia and explorative behavior in Milvago chimango: a comparative analysis across a gradient of urbanization

Here, we analyzed the variability of neophobia and exploratory behavior of Milvago chimango in function of the level of environmental urbanization, as well as the relationship between these two behaviors. In addition, we analyzed the behavioral types present in these birds according to their environment of origin. During non-breeding period, we capture urban (n=13), suburban (n=10) and rural (n=10) birds. These individuals were then housed at individual outdoor aviaries. Two consecutive tests were given to each bird: In the neophobia test we compared the time until feeding in presence or absence of a novel object next to the food. The exploration test consisted in the exposure of each bird to 6 different objects. The latency to approach, contact and the total time spent exploring the objects were recorded. The rural birds showed the highest levels of neophobia. Exploration latency was lower in urban than rural birds, and intermediate in suburban individuals. The highest values of exploration time were found in both urban and rural birds. Neophobia level correlated negatively with exploration time. The differential expression of neophobia and exploration allowed the characterization of birds in three behavioral types according to their environment: suburban as less neophobic, as well as fast and superficial explorers; rural as more neophobic, as well as slow and exhaustive explorers; and urban birds as less neophobic, as well as, fast and exhaustive explorers. The presence of these behavioral types would be related to the structural complexity, resource predictability and predation pressure of each environment.