anecdote now believed of dubious authenticity regarding a 63-year-old bird. Distribution Black-headed gulls can be found over much of Europe. It is also found in across the Palearctic to Japan and east China. Small numbers also breed in northeastern Canada and can be seen in winter in northeast North America as far south as Virginia, often with the similar-looking Bonaparte's Gull and also in some Caribbean islands. Behaviour Eggshell removal Eggshell removal is a behaviour seen in birds once the chicks have hatched, observed mostly to reduce risk of predation. Removing the eggshell acts as a way of camouflage to avoid predators seeing the nest. The further away egg shells are from the nest, the lower the predation risk. Black-headed gull eggs experience predation from different species of birds, foxes, stoats, and even other black-headed gulls. Although mothers show some form of aggressiveness when a predator is near, in the first 30 minutes, wet chicks can be easily taken by other black-headed gulls after hatching when the parents of the wet chick are distracted. Black headed gulls also carry away other objects that do not belong in the nest. The removal of eggshells and other objects is important not only in the incubation period but also during the first few days after the eggs hatch. However, the removal process seems to increase as time goes on. The removal is done by both the male and female parents, normally lasts a few seconds and is done three times a year. A black-headed gull is able to differentiate an egg shell from an egg by acknowledging its thin, serrated, white, edge. Therefore, the weight of the egg or eggshell does not play a role when determining its value. Earlier eggshell removal hypotheses Other hypotheses have attempted to explain the survival value of black-headed gulls removing their eggshells from the nest, including: The sharp edges of the shells after hatching could harm the chicks The eggshell could somehow intrude during the brooding The eggshell could slip over the unhatched egg, creating a double shell Some of the moist organic material left from the shell could lead to a production of bacteria and mould Breeding Begging coordination between siblings Black-headed gulls feed their young by regurgitating onto the ground, rather than into each chick one at a time. The parents tend to accommodate their regurgitation amounts for how intense the nest begging is, from