These are omnivores and opportunists like most "Larus" gulls, and scavenge from garbage dumps, landfill sites, and sewage outflows, with refuse comprising up to half of the bird's diet. It also steals the eggs and young of other birds (including those of other gulls), as well as seeking suitable small prey in fields, on the coast or in urban areas, or robbing plovers or lapwings of their catches. European herring gulls may also dive from the surface of the water or engage in plunge diving in the pursuit of aquatic prey, though they are typically unable to reach depths greater than due to their natural buoyancy. Despite their name, they have no special preference for herrings — in fact, examinations have shown that echinoderms and crustaceans comprised a greater portion of these gulls' stomach contents than fish, although fish is the principal element of regurgitations for nestlings. European herring gulls can frequently be seen to drop shelled prey from a height to break the shell. In addition, the European herring gull has been observed using pieces of bread as bait with which to catch goldfish. Vegetable matter, such as roots, tubers, seeds, grains, nuts, and fruit, is also taken to an extent. Captive European herring gulls typically show aversion to spoiled meat or heavily salted food, unless they are very hungry. The gulls may also rinse food items in water in an attempt to clean them or render them more palatable before swallowing.