The cooked vulture, as seen in the promo video
"Attack of the Giant Vulture" is a short film that appeared on Nickelodeon's "Short Films by Short People" series; a show that showcased short films made by kids. It aired a few times in the late 90s-early 2000s, but has never shown up online.
The short involves a giant vulture chasing a group of kids, culminating with them cooking and eating the bird. Some report that it was particularly frightening for them as children.
The Paley Center for Media are confirmed to have a copy of Nickelodeon's "Creative Lab Comp Reel", a 1:17 hour tape containing the infamous Vulture short; although it is currently unknown whether both NY and CA Paley locations have a copy, or just one of them (the location of the tape isn't specified on their website).
The only footage of the short available online are a few snippets seen in a promo video found on YouTube.
NOTICE (07/12/12)
Anyone interested in seeing Attack of the Giant Vulture should head over here, make an account, and write a comment proving the high demand for the clip. To go one further, please tweet the Paley Center for Media and/or their CEO regarding the clip. With enough numbers, they may just give it to us. See here for additional methods of contact.
The vulture can be seen at 0:10 and 0:19 in this promo.