Gray Heron Life History

Habitat

Gray Herons are at home in shallow freshwater and saltwater habitats. Natural habitats include rivers, lakes, marshes, estuaries, tidal mudflats, and mangroves. This species also utilizes canals, rice fields, fishponds, sewage plants, and agricultural areas.

Food

Gray Herons eat mostly fish, but with adults needing 330–500 g (0.7–1.1 pounds) of food per day, they also prey opportunistically on amphibians, reptiles, mollusks, crustaceans, aquatic insects, small mammals (up to the size of squirrels and young rabbits), and other bird species (especially small ducklings). Typical foraging behavior involves standing motionless and then striking prey, but individuals also wade slowly and occasionally run. These herons usually forage alone in their own feeding territories—about 20 hectares (50 acres) in size—but birds sometimes feed in large groups when food is plentiful. Gray Herons also steal food originally caught by other birds (such as grebes, cormorants, bitterns, raptors, gulls, and crows) and even steal from Eurasian otters.

Nesting

Nest Placement

Usually built in tall trees, 25–50 meters (82–164 feet) above the ground. Sometimes placed on the ground, including on cliffs.

Nest Description

Large stick platform, lined with smaller twigs and vegetation. Herons often reuse and add to nests from the previous year.

Nesting Facts

Behavior

Gray Herons fly with slow wingbeats on heavily bowed wings; in flight, they pull in their neck like other herons (but unlike cranes and storks, which fly with outstretched necks). On the ground, Gray Herons often stand motionless for long periods of time, either resting on one leg or remaining still to surprise unsuspecting prey.

Gray Herons usually breed in small colonies with 2–10 nesting pairs, but they sometimes join larger mixed-species colonies with other herons, ibis, spoonbills, cormorants, storks, and boobies. These mixed colonies can include hundreds or thousands of nests. Gray Herons are socially monogamous, forming pair bonds for a breeding season, but usually breaking up after the season ends. Even while paired, birds often copulate with individuals other than their mate. Males bring nesting material to females, who are the primary nest builders. Both sexes incubate eggs, starting when the first egg is laid. This timing means that chicks hatch at different times, with younger, smaller chicks less likely to survive than early hatching chicks.

Conservation

The International Union for Conservation of Nature lists Gray Heron’s conservation status as Least Concern, due to a very large population (estimated at 790,000–3,700,000 individuals) and an extremely large range. The current population trend is unknown.

Credits

Cramp, S., and K. E. L. Simmons, Editors (1977). The Birds of the Western Palearctic. Volume 1. Ostrich to Ducks. Oxford University Press, Oxford, UK.

International Union for Conservation of Nature (2022). The IUCN Red List of Threatened Species. Version 2022-2. https://www.iucnredlist.org.

Jonsson, L. (1992). Birds of Europe with North Africa and the Middle East. Christopher Helm, London.

Lethaby, N. and Mclaren, I.A. (2002). The identification of Gray Heron. Birding. 34(1): 25–33.

Martínez-Vilalta, A., A. Motis, and G. M. Kirwan (2020). Gray Heron (Ardea cinerea), version 1.0. In Birds of the World (J. del Hoyo, A. Elliott, J. Sargatal, D. A. Christie, and E. de Juana, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.graher1.01

Sibley, D. A. (2014). The Sibley Guide to Birds, second edition. Alfred A. Knopf, New York, NY, USA.

Svensson, L., K. Mullarney, and D. Zetterström (2009). Collins Bird Guide. Second edition. HarperCollins, London, UK.

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