Maybe they were American white pelicans? The one in the quiz is a great white pelican also simply called a "white pelican" (I chose this name so as not to reveal the answer). You made me doubt though. According to Wikipedia and other sources it is 140-180 cm in length, but it does not specify how the length is actually measured and it may vary depending on the position of the pelican in the picture I used. So I went with the beak length for a more accurate measurement and it's actually a bit smaller. I updated the quiz :)