Doi: https://doi.org/10.13157/arla.71.2.2024.sc1
Authors: Gianluca DAMIANI and Mario POSILLICO
E-mail: gianlucadamianiph@gmail.com
Published: Volume 71.2, July 2024. Pages 359-368.
Language: English
Keywords: central Apennines, competition, griffon Vulture, Gyps fulvus, scavengers, shepherd dogs, tourism and wolf
Summary:
Vultures are obligate diurnal scavengers, albeit nocturnal feeding has been reported a few times. The temporal expansion of the trophic niche could potentially offer relief from intraspecific competition, yet at night vultures become more susceptible to predation by mammalian scavengers. We report the first documented case of nocturnal feeding by Griffon Vultures Gyps fulvus in the central Apennines, Italy, a seasonally human-disturbed environment. We monitored a horse carcass for 84 hours, observing 12 feeding attempts: events, whether or not successful, in which vultures tried to feed on the carcass. These attempts ranged from landing around the carcass and approaching it to actually feeding. We also observed ten interactions (occasions in which two or more species came into contact) between vultures and: hikers, wolves and/or shepherd dogs. On average, fewer vultures gathered and eventually fed at night (15.3 ± 16.7, SD) than in daytime (34.5 ± 13.7, SD), when human disturbance and dogs disrupted 43% and 29% of vultures’ feeding attempts, respectively. feeding by vultures occurred in only 20% of interactions. At night, 60% of feeding attempts succeeded, whereas only 14% did so during daytime-twilight. Nocturnal feeding in vultures is influenced by interconnected factors, in a complex costs and benefits framework. Although we observed that human disturbance had a role in daytime-feeding disruption, apparently causing a night shift in feeding activity, given the limited sample size we recommend further research to fully clarify conservation implications and management alternatives. To proactively address these challenges, effective management of domestic dogs and the strategic relocation of carcasses away from frequently used trails should be considered and implemented, whenever feasible.
