Department of Forestry and Natural Resources, Purdue University, West Lafayette, Indiana, United States of America.
Heeke Animal Disease Diagnostic Laboratory, Dubois, Indiana, United States of America.
PLoS One. 2024 Aug 14;19(8):e0307610. doi: 10.1371/journal.pone.0307610. eCollection 2024.
Scavenging is critical for nutrient cycling and maintenance of healthy ecosystems. While there is substantial research into the identification of taphonomic signatures from facultative mammalian scavengers, early stage scavenging signatures by vultures remain unknown. Further, some vulture species are opportunistic predators, highlighting the need to define signatures observed in the course of normal scavenging behavior. We placed stillborn neonatal calves in an unoccupied pasture and used motion-trigger camera traps to quantify scavenging effort, then conducted necropsies to evaluate the effect of black vulture (Coragyps atratus) and turkey vulture (Cathartes aura) scavenging effort on carcass consumption. We measured the order of consumption of different tissue types to delineate which anatomic structures vultures consume first. Scavenging trials with higher numbers of vultures feeding on the carcass for longer were associated with decreased remaining tongue and abdominal viscera, and a larger umbilical wound. Greater maximum flock sizes were associated with decreased remaining tongue and abdominal viscera, a larger umbilical wound, and greater biomass consumption. Black vultures targeted the perineum and tongue earlier, while turkey vultures targeted the eyes, perineum, and tongue. These results are consistent with the idea that vultures prefer tissues that are easy to access and contain high nutrient content. These patterns form a distinctive taphonomic signature that can be used to identify early scavenging by black and turkey vultures. Our results demonstrate that criteria commonly used to identify livestock depredation by black vultures only document vulture presence and not predation. This distinction implies that new and more definitive criteria need to be developed and put into practice for more accurate decision criteria in livestock depredation compensation programs.
清道夫活动对于营养物质循环和维持健康的生态系统至关重要。虽然已经有大量研究致力于鉴定兼性哺乳动物清道夫的化石特征，但秃鹫早期清道夫的特征仍不清楚。此外，一些秃鹫物种是机会主义捕食者，这突出表明需要定义在正常清道夫行为过程中观察到的特征。我们将死产的新生牛犊放置在无人居住的牧场上，并使用运动触发相机陷阱来量化清道夫的努力，然后进行尸检以评估黑秃鹫（Coragyps atratus）和火鸡秃鹫（Cathartes aura）清道夫努力对尸体消耗的影响。我们测量了不同组织类型的消耗顺序，以划定秃鹫首先消耗的解剖结构。有更多秃鹫在更长时间内以更高的数量在尸体上进食的清道夫试验与剩余的舌头和腹部内脏减少以及更大的脐部伤口有关。更大的最大鸟群大小与剩余的舌头和腹部内脏减少、更大的脐部伤口和更大的生物量消耗有关。黑秃鹫更早地瞄准会阴和舌头，而火鸡秃鹫则瞄准眼睛、会阴和舌头。这些结果与秃鹫更喜欢容易获取且富含营养的组织的观点一致。这些模式形成了独特的化石特征，可以用来识别黑秃鹫和火鸡秃鹫的早期清道夫行为。我们的结果表明，通常用于鉴定黑秃鹫对牲畜掠夺的标准仅记录秃鹫的存在，而不记录捕食。这种区别意味着需要制定和实施新的、更明确的标准，以便在牲畜掠夺赔偿计划中制定更准确的决策标准。
