North America's biggest heron hunts fish, frogs, voles and even rabbits
The great blue heron stands taller than a metre, yet usually weighs little more than two kilograms. Fish are its staple, but this patient wader of North American wetlands will spear frogs, snakes and voles, swallow its catch whole, and occasionally choke on something too big.
No heron native to North America is larger, and worldwide only the Goliath heron and the white-bellied heron beat it. Adults measure 91 to 137 cm from beak to tail, with wings spanning up to about two metres. Males are slightly bigger than females but otherwise look alike: slate-blue flight feathers, rusty thighs, a nearly white face and black plumes sweeping back from above the eye. At the start of the breeding season, the dull yellow bill and grey legs briefly turn orange. In flight it folds its neck into an S, the easiest way to tell it from a crane, which flies with its neck straight.
It lives from Alaska and southern Canada in summer down through Mexico and the Caribbean to the Galápagos. Northern birds east of the Rockies migrate, though tough individuals stay through winter wherever running water stays unfrozen. Almost any wetland will do, including busy city waterways with fish in them. In South Florida and the Caribbean lives an all-white form, the great white heron, which is heavier and may even be a separate species, a view David Sibley has lent some support.
Most hunting happens in water under half a metre deep, especially at dawn and dusk. The heron wades slowly and strikes with its sharp bill, but it also hovers, dives headfirst, drops feet-first from perches and even floats. Diets vary by place: in Nova Scotia flounder made up 98 percent of meals, while one Idaho study found voles supplied between a quarter and two-fifths. Snakes more than a metre long, young cottontail rabbits and the occasional small bird have also been recorded.
Breeding pairs gather in colonies called heronries, usually in trees near water and often on islands safe from predators. Colonies range from five to 500 nests, averaging around 160, and usually sit within a few kilometres of good feeding grounds.
Source: Great blue heron
