title: Responses of urban crows to con- and hetero-specific alarm calls in predator and non-predator zoo enclosures.
abstract: Urban animals and birds in particular are able to cope with diverse novel threats in a city environment such as avoiding novel, unfamiliar predators. Predator avoidance often includes alarm signals that can be used also by hetero-specifics, which is mainly the case in mixed-species flocks. It can also occur when species do not form flocks but co-occur together. In this study we tested whether urban crows use alarm calls of conspecifics and hetero-specifics (jackdaws, Corvus monedula) differently in a predator and a non-predator context with partly novel and unfamiliar zoo animal species. Birds were tested at the Tiergarten Schönbrunn in the city of Vienna by playing back con- and hetero-specific alarm calls and control stimuli (great tit song and no stimuli) at predator (wolf, polar bear) and non-predator (eland antelope and cranes, peccaries) enclosures. We recorded responses of crows as the percentage of birds flying away after hearing the playback (out of those present before the playback) and as the number of vocalizations given by the present birds. A significantly higher percentage of crows flew away after hearing either con- or hetero-specific alarm calls, but it did not significantly differ between the predator and the non-predator context. Crows treated jackdaw calls just as crow calls, indicating that they make proper use of hetero-specific alarm calls. Responding similarly in both contexts may suggest that the crows were uncertain about the threat a particular zoo animal represents and were generally cautious. In the predator context, however, a high percentage of crows also flew away upon hearing the great tit control song which suggests that they may still evaluate those species which occasionally killed crows as more dangerous and respond to any conspicuous sound.
authors: Faculty of Science, University of South Bohemia, Branišovská 1760, 37005, České Budějovice, Czech Republic.
authors: Kateřina
authors: K
authors: Bílá
authors: Faculty of Science, University of South Bohemia, Branišovská 1760, 37005, České Budějovice, Czech Republic.
authors: Jana
authors: J
authors: Beránková
authors: Faculty of Science, University of South Bohemia, Branišovská 1760, 37005, České Budějovice, Czech Republic. petr-vesely@seznam.cz.
authors: Petr
authors: P
authors: Veselý
authors: Department of Cognitive Biology, University of Vienna, Althanstrasse 14, 1090, Vienna, Austria.
authors: Thomas
authors: T
authors: Bugnyar
authors: Department of Cognitive Biology, University of Vienna, Althanstrasse 14, 1090, Vienna, Austria.|Comparative Cognition, Messerli Research Institute, University of Veterinary Medicine Vienna, Medical University of Vienna and University of Vienna, 1210, Vienna, Austria.
authors: Christine
authors: C
authors: Schwab
mesh_terms: D000818:Animals; D000836:Animals, Zoo; D001717:Birds; D002947:Cities; D046368:Crows; D014828:Vocalization, Animal
keywords: Alarm call; Carrion crow; Communication; Conspecific signal; Hetero-specific signal; Inter-specific signalling; Predator avoidance