Yes, laughing gulls (Leucophaeus atricilla) do indeed appear to laugh! I included them in my Staten Island Beach Party video from 2019, and you really get to hear them squawking at each other. I saw my first laughing gulls on a Rockaway beach near Beach 116 a few years back, and have enjoyed seeing them all over New York City and Long Island.
Laughing gull, Nickerson Beach, Long Island, July 2, 2019
Laughing gull, Great Kills Park, Staten Island, April 14, 2022
Laughing gull, Nickerson Beach, May 17, 2019