Primeval: Episode 6

Lester's rival, Christine Johnson, and a small military force invade the ARC in search of a mysterious artifact, Escaping to a mysterious old hut, the team thinks they've found refuge—until an anomaly opens nearby. Phorusrhacids, 10-foot-tall killer birds from the Pliocene Epoch, emerge.The team uses all its ingenuity to keep the rapacious birds at bay. Without any technology at their disposal, they rely on nothing more than bare hands and whatever they can find in the hut, which has been empty since the 1930s.