Old World Warblers: Sylviidae

These birds have a wide distribution, including the subarctic, Europe, Asia, Africa, North and South America, Australia, and Pacific islands.

Old World warblers occupy a variety of habitats from arid scrubland to islands in the ocean, and every habitable niche in between, ranging from sea level to as high as several thousand feet (meters). Many species occupy specific levels within a habitat, with one species claiming the higher portions, as in the forest canopy, and others claiming lower regions such as bushes or the forest floor.

Generally, this family of birds lives on insects and spiders. Some species eat snails and small crustaceans. Others, such as the golden-crowned kinglet and some African species, feed on nectar and sap. Some large reed warblers eat fish and frogs. Young hatchlings eat insects and occasionally berries. Migratory birds change their diets to berries and fruit in order to have enough stored fat for flying long distances.

Since Old World warblers are insect eaters, they hold the potential to be effective pest control for farmers and timber producers. Some nectar-eating species may also act as pollinators for cultivated plants.

Several species are threatened, or at high risk of becoming extinct, or dying out. Fifteen species of marsh warbler are at high risk of becoming extinct. These species are experiencing population declines due to their isolation on oceanic islands where their habitats are being reduced.