may migrate over part of their range. This can also include regular commutes from nesting sites to feeding areas. Wood storks have been observed feeding from their breeding colony. Behaviour Feeding and diet Storks are carnivorous predators, taking a range of reptiles, small mammals, insects, fish, amphibians and other small invertebrates. Any plant material consumed is usually by accident. Mycteria storks are specialists in feeding on aquatic vertebrates, particularly when prey is concentrated by lowering water levels or flooding into shallows. On marine mudflats and mangrove swamps in Sumatra, milky storks feed on mudskippers, probing the burrow with the bill and even the whole head into the mud. The characteristic feeding method involves standing or walking in shallow water and holding the bill submerged in the water. When contact is made with prey the bill reflexively snaps shut in 25 milliseconds, one of the fastest reactions known in any vertebrate. The reaction is able to distinguish between prey items and inanimate objects like branches, although the exact mechanism is unknown. Openbills are specialists in freshwater molluscs, particularly apple snails. They feed in small groups, and sometimes African openbills ride on the backs of hippos while foraging. Having caught a snail it will return to land or at least to the shallows to eat it. The fine tip of the bill of the openbills is used to open the snail, and the saliva has a narcotic effect, which causes the snail to relax and simplifies the process of extraction. The other genera of storks are more generalised. Ciconia storks are very generalised in their diets, although Abdim's stork is something of a specialist in feeding in large flocks on swarms of locusts and at wildfires, although other storks will opportunistically feed in this way if the opportunity arises. This is why white storks and Abdim's storks are known as "grasshopper birds". Ephippiorhynchus are carnivorous though have a very diverse diet when living on human modified habitats such as agricultural landscapes. The foraging method used by the generalists is to stalk or walk across grassland or shallow water, watching for prey. Breeding Storks range from being solitary breeders through loose breeding associations to fully colonial. The jabiru, Ephippiorhynchus storks and several species of Ciconia are entirely solitary when breeding. In contrast the Mycteria storks, Abdim's stork, openbills and Leptoptilos storks all breed in colonies which can range from a couple of pairs