A Terror Bird ( Titanis) appeared in Series 3 to Series 4. They first appear in episode 3.6. They first came through the anomaly in the 1950's, and attacked and killed scientists that were studying the anomaly. When the anomaly reopened in the present day, they came through again, and one was drawn to a cabin the team were hiding it due to a distress call they had accidentally played. It chased the team in their car, and Danny Quinn fought it off with a pipe before tey crashed. Abby Maitland and Sarah Page fled while Danny used Connor Temple as bait to draw in the bird, trapping it by hooking its leg into the car's tow cable. Abby and Sarah were chased by several more and chased to a minefield along with Danny and Connor, and Danny lured on onto a mine, killing it. Another attacked and killed one of Captain Ross's soldiers and was killed as the car exploded on a mine and the shrapnel cut through the bird's neck. The rest of the flock attack the cabin, and Connor distracted them so that Danny could play the distress call recording to lure them back to the anomaly.
A single terror bird attacked in a prison in episode 4.7, coming through a "satellite anomaly" and killing a tourist. It returned through the main anomaly and was driven back by the team, however it appeared through another satellite anomaly Abby and Becker found. It was allowed to go through the main anomaly, but it returned again to distract the team as they were attempting to capture Ethan Dobrowski. Connor and Abby chased after it, and Danny arrived to help knock it through a satellite anomaly. Again the terror bird returned, this time being brought down by Matt Anderson's EMD. Abby contained it in a storage closet, but it was set free by Ethan/Patrick to menace Emily merchant, but luckily used a club to bring it down again. It was presumably returned back to its own time after that.