Gavin is first seen in the underground Dinosaur World, stealing an egg from a Triceratops along with his children, only to be stopped by Buck the weasel who manages to fight all three of them and defeat them. Later, after Buck goes to the surface and finds his friends - the Herd. They listen to their conversation and hear that an enormous asteroid is going to crash on Earth and kill all life and Buck plans to stop it. After they leave, Gavin tells his children the must stop Buck from stopping the asteroid.
Concluding that due to their ability to fly, they will be able to survive, whilst the mammals will not. Afterwards, they track down the Herd and he reveals he is going to kill them, so they will not save all lives, and so he can rule the Earth later. Thankfully, Buck manages to lead the Herd to the forest and once again defeat Gavin and his children. They try to repeat their attack later during a storm, but end up getting electrocuted, sending all three of them paralleling towards the ground and into the trees, crashing into the ground.
During nighttime, Gavin orders his son Roger to kidnap Buck, but he accidentally takes Granny, Sid the sloth's grandmother. Gavin tries to eat her, but fails and Granny starts dragging around inside his abdomen. Gertie instead help Gavin barf up Granny and throws her off the ledge they were on, where she finds Geotopia. Finally, the Herd realize that the reason the meteor is coming is because of a magnetic attraction between the remains of the previous meteors that crashed on Earth, so they try to fill a volcano with the remains in order to blast it off to space and pull the meteor away.
Gavin, Roger, and Gertie intervene by grabbing and throwing the largest part off the mountain. Gavin then orders Roger to kill Buck, and reveals him his scheme. However, Roger realizes that they will not be able to survive the meteor's crashing. So he finally stands up to his father and manages to talk him into helping the Herd. So Gavin, Gertie and Roger help throw the meteor parts in the mountain. Suddenly Gavin saw a giant meteor flies coming towards Roger and Gertie and bravely jumps in the way to protect them. The rock knocks them all to the ground. However none of them are hurt. Afterwards, they appeared dancing to Brooke's song in Julian and Peaches' wedding.
Gavin is a brave, tough, valiant, and courageous dino-bird who loves his children. However, his unsparing and ruthless nature often keeps him from thinking clearly as he was more concerned on getting revenge on Buck than helping the herd stop the asteroid. However, with some convincing from his children, Gavin spares the weasel's life, so they could save the planet.
Despite the fact he is named “Gavin” in the film's promotion and in the credits, his name is never said in the film.
Gavin is the second main antagonist of an Ice Age movie who does not die at the end of his movie, behind Rudy, or the third if Gutt survived his ordeal with the sirens.
Gavin is the fifth main antagonist of a Blue Sky movie who doesn't die at the end of his film, after Sour Kangaroo from Horton Hears A Who!, Rudy, and Nigel from Rio.
Gavin is also the fourth main antagonist of a Blue Sky film to be a parent after Madame Gasket in Robots, Sour Kangaroo, and Mandrake in Epic.
Gavin is the first main antagonist of an Ice Age movie who redeems himself.
He is also the second main antagonist of the Blue Sky film who redeems himself after Sour Kangaroo.
Gavin is the third Ice Age villain who can fly, behind The Lone Gunslinger and Silas, one of Gutt's henchmen.
Gavin's voice actor, Nick Offerman occasionally co-stars with Aziz Ansari, who voiced Squint, another one of Gutt's henchmen from, on Parks and Recreation.
He, Soto and Captain Gutt are also the only three main villains in the Ice Age franchise to be anthropomorphized, unlike Cretaceous and Maelstrom, and Rudy.
Gavin is the third main antagonist of the Ice Age franchise to be actually evil, with the first being Soto and the second being Gutt. However, unlike his predecessors, Gavin is more of a comedic villain and later redeems himself for the sake of his family.
Gavin is the first main antagonist of the fifth film of a computer-animated series.