Presence of Bone Remains in the Ossuaries of Bearded Vultures (Gypaetus Barbatus): Storage or Nutritive Rejection

[摘要] Ossuaries, or bone-breaking sites, are used by Bearded Vultures (Gypaetus barbatus) to prepare and store bone remains. The different nutritive values of different parts of the skeleton and bones and the fact that many remains stay in the ossuary for long periods without being consumed suggest that they may have another use besides storage. I tested whether the presence of bone remains in ossuaries may result from selection ("nutrient concentration" hypothesis) and rejection of bone remains on the basis of nutritive value. Of the remains found at the study sites, 84.9% belonged to medium-sized ungulates, 11.6% to large mammals, 2.5% to carnivores, and 1% to Suidae. Bone remains found were principally scapulas (14.9%), vertebrae (13.2%), skulls (12.5%), tibias (10.7%), mandibles (9.3%), ribs (8.3%), and humeri (7.2%). The larger proportion of less-nutritious skeletal parts (i.e., containing less oleic acid) and the significantly smaller proportion of distal epiphyses, which are more nutritious, support the nutrient concentration hypothesis. On the other hand, the scarce presence of remains of large mammals and Suidae and the high presence of scapulae, vertebrae, and skulls suggest that handling efficiency can also influence food selection. Bone selection based on nutritive value may allow Bearded Vultures to optimize parental foraging effort and maximize fitness.

[学科分类] 动物科学

[关键词] Bearded Vulture;bone-breaking sites;food preferences;foraging theory;Gypaetus barbatus;nutritive selection;ossuaries