Herons are medium-to-large wading birds in the family Ardeidae, with 72 recognized species, including egrets and bitterns. The genera Botaurus and Ixobrychus are known as bitterns. Egrets, often white and adorned with breeding plumage, are the same biologically as herons. These birds are distinguished by their long legs, necks, and beaks, and unlike similar families such as storks or ibises, herons fly with retracted necks. They are also characterized by powder down on their plumage. Most herons nest colonially in trees, while bitterns prefer reed beds. "Siege" is the term used for a group of herons.
The English name "heron" dates back to around 1300, with French and Proto-Germanic origins. They are also colloquially known as shitepokes, reflecting their behavior when startled. The name shitepoke and other variations have historical references including in Shakespeare's work and royal decrees.
Herons have a cosmopolitan distribution, found on every continent except Antarctica, typically in lowland regions close to water such as lakes, rivers, and coasts. They exhibit partial migration habits. Their carnivorous diet primarily consists of aquatic life. Unique hunting strategies involve elements of stealth, patience, and occasional use of bait to lure prey. Heron species are generally monogamous and colonial breeders with seasonal nesting, predominantly laying glossy blue or white eggs.
Taxonomically, herons have been difficult to categorize correctly, with unresolved relationships between species and genera. Research suggests three main groups within the family: tiger herons and the boatbill, bitterns, and a combination of day herons, egrets, and night herons. The family is now classified under the order Pelecaniformes by the International Ornithological Congress. Fossil evidence has also contributed to understanding the evolution and history of herons, with several extinct species identified through remains.