Seabirds and shorebirds are important predators in both the subtidal (marine) and intertidal ecosystems of Southern Africa. They are not distributed randomly, their distribution patterns being determined by the availability of food and nesting sites. Seabirds feed at sea and breed on land, and so are important redistributors of nutrients. Deposition of guano raises the level of nutrient in the vicinity of seabird breeding colonies and the effects of this are evident in the plant and animal communities of the intertidal and nearshore regions. Seabirds prey on species which are of commercial importance, and this, coupled with the need to conserve decreasing populations of many seabirds, has been the stimulus for much research to date. Shorebirds also consume species of importance to man, and in some areas are important determinants of the community structure of invertebrates. Current research into sea and shorebird populations is adopting an ecosystem rather than an autecological approach. Researchers are attempting to answer such questions as whether competition between seabirds and man for food really exists, what causes coastal bird populations to decrease, and what can be learnt by studying the behaviour and ecology of coastal birds that will help towards the effective management of shared resources.