They first appear in Burger Beard's ship playing cards while Burger Beard was off on the island above Bikini Bottom. When Burger Beard got knocked from the island to his ship with a book that portrayed the beginning part of the movie, they wanted him to read the book to them. He stopped the book at the post-apocalyptic Bikini Bottom calling it "THE END" until the seagulls made him continue reading (by threatening to poop all over him).
As he continued reading, they eventually washed up on land where they found out that his ship was also a food truck where he would be selling Krabby Patties. The Seagull Crew refused to leave until he finished the story. He answered he would but offered up a snack, which turned out to be Hot Wings. That led to the others to point out that Kyle wasn't there (he had been in a port-a-potty that was bird size at the moment), which scared the others off. Meanwhile Kyle came out of a port-a-potty and was scared the wings off by Burger Beard too. Kyle called a cab since he couldn't fly.
They are seen a few times when Burger Beard was fighting against SpongeBob/Invincibubble, Patrick/Mr. Superawesomeness, Squidward/Sour Note, Mr. Krabs/Sir Pinch-A-Lot, and Sandy/The Rodent.
At the end after Burger Beard landed back on the same island, the birds caught up with him having him to sing the Theme Song with them. He finally agreed to it (since he could not find a way to say no to Kyle.)
It the U.K. the seagulls have different voice actors. This even carries over into the Rap Battle
The seagulls who had word speaking dialogue all have male voices except for Stacey Solomon, that is an actress.