- « "These vicious carnivores used their heavy beaks to batter obstacles and tear flesh, and left little of their victims intact. Flightless birds, these 8-foot-tall predators could none the less run 65 km/h – making them pretty difficult to take down. " »
- — Primeval: New World official description
Terror Birds possessed heavily-built bodies - with a long, curved neck, which held a large head equipped with a giant, hooked beak, and small wings which were useless for flight. They also possessed very large legs, which allowed them to run at incredible speeds and quickly chase down extremely fast prey; Titanis walleri could run at 65 km/h, and outrun a motorcycle going at full or near-full speed. Terror Birds began as two-foot younglings, maturing to be about eight - ten feet tall. Terror Birds apparently matured quickly, since Leggy grew from a small juvenile to an adult over the course of only a few months. (Angry Birds, The Great Escape)
Terror Birds apparently lived in flocks and packs, and were vicious and aggressive predators in the woods and wilderness. It would appear that how the Terror Birds attacked their prey differed somewhat between different groups: the first flock encountered by the ARC team appeared to devour and kill prey simply by chasing it down and then pecking chunks of flesh off of it with their large beaks; while the Titanis walleri encountered by the Special Projects Group were shown to kill prey by pinning it down with their large feet, and then using their large beaks to tear the prey's flesh away. (Episode 3.6, Angry Birds) One common hunting attribute between all the differing Terror Birds was that they tended to eat their prey alive.
Terror Birds were usually hunters, but one individual specimen in particular (who had grown up being brutally examined and experimented on in a laboratory) was instead a scavenger; eating and scavenging any leftover food such as human snacks he could find, although he would still attack and kill humans on sight. (The Great Escape)
Incursions and encounters
A flock of Terror Birds came through an Anomaly to a rural war cabin in the early 20th Century. They apparently killed John Mortimer's scientific team after the team encountered the Birds in the woods, and then disappeared (most likely back through the Anomaly).
When the war cabin Anomaly reopened circa 2009 - 2010, the Terror Birds came through again. One of the Birds attacked Danny Quinn, Connor Temple, Abby Maitland and Sarah Page, and chased their car through the woods until they crashed the car. The Terror Bird later returned to the crashed car and attacked Connor and Danny, but the two were able to escape and capture the Bird in a snare trap.
Shortly after, Sarah and Abby encountered the other Terror Birds in a dead crop, and the flock began attacking the team. One of the Birds was blown up when Danny tricked it into stepping on a landmine, and another attacked Ross, killing his fellow soldier, and was subsequently decapitated when Ross' car was blown up by a landmine, and the explosion sent one of the car's wheel spinners into the Terror Bird's neck.
The team then retreated to the war cabin, and the other Terror Birds attacked and began to break inside. When Danny tried to escape from the cabin to the Anomaly by climbing along a power line, several Birds tried to pull him down before Connor lured them away. Just before the Birds managed to reach the team inside the war cabin, a recording of a Terror Bird distress call drew the Birds back through the Anomaly, which closed shortly after.
A Terror Bird came through one of two Anomalies that had opened on the exact same spot in a prison circa 2011. It came into a prison cell via a satellite Anomaly and immediately killed a tourist and dragged him back through. The Terror Bird later returned through the merged pair Anomalies right in front of Connor, Abby and Hilary Becker, who scared it back through using EMDs.
The Terror Bird soon came back through a satellite Anomaly in a storage closet, but returned through before the satellite Anomaly closed. As Connor, Abby and Matt discussed the situation, the Terror Bird entered the room, having come back through another satellite Anomaly. The Bird ignored them and travelled through the original, merged pair of Anomalies.
Later, while the team were searching for Patrick Quinn in the main room of the prison, the Terror Bird came back and ran into the prison dungeon. Connor and Abby chased after the creature and located it inside a room. Along with Danny, they slowly spread out, and the Bird attacked Abby. Danny coaxed the Bird towards him and then beat it back through a satellite Anomaly with Molly. The Terror Bird was sent to another part of the prison where Matt had Patrick cornered and shot it down. The Bird was then locked away in storage cupboard.
Patrick later freed the Terror Bird from the storage cupboard and left it to kill Emily Merchant; but Emily was able to beat the Terror Bird unconscious with Molly. The Bird was presumably returned through the Anomaly shortly afterwards.
Three Terror Birds (two adults and a juvenile), specifically Titanis walleri, came through an Anomaly to the New West Warehouse district in early 2012. The juvenile was found by Blake and Skeezer in their marijuana crop aboard an abandoned train, and kept by Skeezer in the two's makeshift home aboard the train. Skeezer initially fed his cheese puffs to the juvenile Terror Bird, and then later kept it in a cardboard box; and he also dubbed it "Leggy". The adult Birds, meanwhile, prowled the area, with at least one of them prowling the nearby woods.
The adult Terror Bird prowling the woods stalked and eventually attacked a motorcyclist on the road, sending him crashing off the road. The Bird then devoured him, leaving only his leg and motorcycle gear. Later, the Bird was accidentally hit by Mac Rendell's truck, but survived and managed to flee back to the warehouse district.
At the warehouse district, the second adult Terror Bird stalked Evan Cross in a warehouse filled with old trains. It then attacked and pursued Evan and Ken Leeds through the maze of trains, and managed to wound Evan in the leg while trying to reach him through the gap between two train carts. Mac then arrived and quickly tranquilised the Bird by shooting it with numerous tranquiliser darts.
The other adult then arrived and chased Evan, Mac and Leeds, cornering them in a train's cargo cart. Initially, the Terror Bird tried to break the cart's door down, but eventually started looking for other ways in. After some time, the Bird abandoned its attack on Mac, Leeds and Evan and went off. It attacked Blake in the maze of old trains, devouring flesh from his back until it was unintentionally alerted that the Cross Photonics team were watching it from nearby. The Terror Bird then pursued the team through the warehouse and outside.
Shortly after, Dylan Weir lured the Terror Bird aboard a train, and the Bird chased her through the train into a carriage filled with vapours from burning marijuana. Dylan managed to escape the Bird, and the team locked it inside the marijuana-filled carriage to be knocked out by the marijuana vapours. One of the adult Terror Birds apparently died (most likely from drug overdose). The other adult was returned through the Anomaly, and Leggy was secretly taken by Leeds.
After Leeds took Leggy, he handed the juvenile Terror Bird over to the military to get Project Magnet reactivated. Leggy was subsequently raised in a government laboratory, and was subjected to numerous painful and cruel experiments. After a few months, by which time Leggy had grown to adulthood, the Terror Bird managed to break out of his cage and escape from the lab into Vancouver when a doctor attempted to sedate him for rectal biopsy.
Leggy subsequently travelled to a parking garage, where he attacked a druggy's parked car before fleeing into an alley outside. Evan Cross, Dylan Weir and a squad of soldiers led by Major Douglas later found Leggy in the alley scavenging through a dumpster, but the Terror Bird fled and escaped when Douglas' men tried to tranquilise him.
Leggy next travelled to the Thunderbird Sports Arena and stalked the arena's underground maintenance tunnels, eating snacks he came across there and chewing off the tracking device on his leg. He also ambushed and killed Corporal Turner when the latter entered the tunnels. Leggy subsequently travelled out of the tunnels and into the arena's ice-skating area, where he attacked Major Douglas and his soldiers; killing at least one of them and injuring Douglas, before Sergeant Macready fended Leggy off by shooting the Terror Bird in the leg.
The injured Leggy then went out onto the ice rink, before fleeing back into the maintenance tunnels when Evan and Dylan shot him with tranquilisers in a failed attempt to tranquilise the Bird. Leggy hid in the maintenance tunnels until Evan and Dylan lured him out of hiding with a trail of cheese puffs and fake squawks, then shot him with a tranquiliser once he was close enough. Leggy then noticed Evan and Dylan and tried to attack, before succumbing to the tranquiliser. Upon concluding that Leggy could not be saved, Dylan shot and killed the Terror Bird as a mercy killing.
Leggy was seen in Evan Cross' flashbacks of the second Terror Bird incursion involving Leggy.
Terror Birds lived from approximately 62 to 2.5 million years ago, primarily in South America but also in North America. Terror Birds were carnivorous and were apex predators, and it is thought that they used their large feet and talons to beat and hold their prey down, while their deadly beaks were used to peck and wound the prey to the point of death before devouring it. Terror Birds vanished from the fossil record during the Pleistocene; it is thought that they went extinct due to other predators migrating into the Americas and causing a growth in competition for the Terror Birds.
- As the Terror Bird in Episode 4.7 had noticeable physical differences from the Terror Birds in Episode 3.6, and the ones in Primeval: New World had physical differences from both the kinds of Terror Bird that appeared in the original Primeval show, it is generally believed by fans that the three different-looking kinds of Terror Bird were different species to each other.
- While the Terror Birds in Primeval: New World were identified as Titanis walleri, it is unknown what species the Birds in the original Primeval show were. Some sources state that the original show's Terror Birds were Titanis, while others state that they were another species of Phorusrhacid. (however, the Pteranodon's look changed between Primeval and Primeval: New World, and this may have been happened with Titanis, too) Abby's Sketchbook identifies the original Primeval Terror Birds as Phorusrhacos (Or at least Series 3 ones meaning the Terror Bird of Series 4 may be another species different to Titanis and Phorusrhacos)
- The sound effects used for the vocalisations of the Titanis walleri in Primeval: New World were previously used for the Tree Creepers in Primeval.
- In Episode 4.2, an archive shot of one of the Terror Birds that appeared in Episode 3.6 was used for a picture of a creature on Creaturedepository.com. Due to this, some fans believe that canonically, the creature seen on the website may have been a Terror Bird.
- The Terror Birds from Series 3 bear a resemblance to the ones from the 2008 film 10,000 B.C.
- While the Terror Bird from Series 4 shared the body of the ones from Series 3, it had plumage like a condor.
- On the original Primeval website, the show's Terror Birds were mentioned living in the Miocene and Cenozoic epochs. Although Terror Birds existed in the Miocene in real life, the Cenozoic was actually an era, not an epoch.