Cautious Crows: Neophobia in Torresian Crows (Corvus orru) Compared with Three Other Corvoids in Suburban Australia

摘要

Corvids (Family: CORVIDAE) are a clade of some 120 species widespread throughout much of the world that have attracted the interest of researchers due to their impressive cognitive abilities. The group is, however, also generally described as neophobic, a trait that increases the difficulty of undertaking such research. In Australia, Torresian crows (Corvus orru) have, like corvid species worldwide, thrived in urban environments, sharing this habitat with a number of other corvoid (Superfamily: CORVOIDEA) species. While each of these species has successfully colonised urban areas, the extent to which neophobia is present is not known. This study empirically tested the extent to which neophobia is exhibited in wild urban Torresian crows by measuring the delaying effect of a novel object to obtaining food and any changes in neophobic behaviours displayed. This was then compared with the other urban corvoid species that inhabit similar niches. This study confirmed that Torresian crows are significantly wary of a novel objects, displaying more neophobic behaviours and taking longer to attain the food. Crow behaviour provided evidence in support of both the dangerous niche hypothesis and the two-factor model of neophobia and neophilia. Crows also displayed these behaviours to a significantly greater extent than the three other corvoids studied. However, the individual variation in crow behaviours when exposed to a novel object was extensive. This variation may be attributed to differing behavioural types between individuals, or different experiences with novel objects or humans in the bird's past.