Feeding behaviour of Ivory Gulls

On a recent trip to Svalbard I had the opportunity to watch Ivory Gulls feeding. They would follow the ship as it made it's way through the ice and plunge down into the water to snatch up small fish from just below the surface. They appeared to be much more agile than the accompanying Fulmars and Kittiwakes and seemed to have a higher catch rate than the other birds.