Herons fly with necks coiled, then spear by refraction
Herons—seventy-five species of long-legged Ardeidae, including egrets and bitterns—retract S-shaped necks in flight unlike storks or cranes. At the water's edge they sway their heads to correct for light bending, then harpoon fish with bills built like spears.
Sizes span the dwarf bittern at 25–30 cm to the goliath heron standing up to 152 cm. Twenty or twenty-one specialized cervical vertebrae let them fold the neck tight; day herons wear longer necks than night herons and bitterns. Bills run from the agami's needle to the boat-billed heron's broad scoop—the former Cochlearidae family now folded into Ardeidae. Powder down, colonial tree nests for many species, and reed-bed solitude for bitterns further set them apart. English "heron" arrives around 1300 from Old French; folk names include shitepoke, and a group is a "siege."
Distribution is cosmopolitan except Antarctica, avoiding only high Arctic, extreme alpine cold, and driest deserts. Almost all hug water margins yet barely swim. Grey herons stay put in Britain but migrate from Scandinavia; post-breeding dispersal often precedes night migration in small groups. Diets cover fish, amphibians, crustaceans—yellow-crowned night herons favor crabs—plus opportunistic birds, rodents, and rare plant matter. Sit-and-wait hunting alternates with slow walks under sixty paces a minute, foot-stirring, and the black heron's full wing canopy. Little egrets and grey herons have used bait, even Amazonian striated herons dropping seeds and insects; cattle egrets gain about 3.6 times the capture success by following grazers.
Most are monogamous; day and night herons often colonial, bitterns solitary. Clutches usually three to seven glossy blue or white eggs (olive-brown in large bitterns). DNA work overturned an old skull-based split into purely diurnal versus nocturnal groups, showing convergent feeding skulls instead.
Patience, optics, and a folded neck: the wetlands' spear is a study in delayed motion.
Source: Heron
