From July through September 2007, three pig carcasses (Sus scrofa), weighing
between 60 and 140 pounds were placed outside in a grassy area in central Texas. A
surrounding fence was built to prevent entrance by terrestrial scavengers, while allowing
avian scavengers unrestricted access. Modification of the pig carcasses was recorded
through the use of two motion-sensing digital cameras and daily on-site observations.
Two species of vultures, the American black vulture (Coragyps atratus) and turkey
vulture (Cathartes aura), both waited approximately 24 hours before beginning to
scavenge and did not feed at night. They completely skeletonized the pig carcasses in 3
to 26 hours of feeding. Vultures were observed manipulating the carcasses, and their
activity left scratches on the bones, which can be utilized as specific indicators of vulture
scene modification and body alteration. The accelerated rate of decomposition and the signature markings on the bones are important factors to consider when interpreting
taphonomic events and determining an accurate postmortem interval at vulture modified scenes.