Grey Heron Fact File
The grey heron is a large species of heron found across much of Europe, Africa and Asia. Occasionally they will also visit Australia and a record exists from New Zealand.
These birds use their long neck to seize prey and their pointed bill to stab it. They will wait motionless at the water's edge for fish to swim past. Small mammals, reptiles and other small animals are also consumed.
Up to 10 eggs are raised in a nest built out of sticks.
Their population is threatened through persecution due to their predation of fish stocks, habitat destruction and disease.
Read on to learn more about these brilliant birds.
The grey heron is covered with grey feathers across the back and wing with white feathers along the neck and head. Running back from the eye across the head is a black stripe. Black patches of feathers are also located on the shoulders. This terminates with a black crest hanging behind the head. On the chest are ruffles of white feathers.
The bill is long and pointed at the tip. It is colored orange. They eye is yellow with a round black pupil.
Grey Herons are well adapted to spend much of their life near water. Their long legs end with long, thin toes. Often they are seen resting while on just one leg. The legs are colored grey-green or yellow-brown.
Their color varies during the breeding season. The iris, bill and legs turn orange or red.
An adult will stand at between 84cm and 1m (33in and 3.3ft) tall with an average weight between 1 and 2kg (2.2 and 4.25lbs). They have a wingspan of 1.5-1.7m (4.9-6.5ft) across.
Males and females look similar but males tend to be slightly larger than females.
Grey herons are carnivores. Their diet includes fish, invertebrates, birds, reptiles and small mammals.
They will wait by the water's edge until the prey comes within striking range. When it does they will extend the neck and stab it with the bill. Small fish are swallowed whole, with larger prey carried back to land to eat.
Their sixth vertebrae is elongated and this makes their neck extend further than that of other birds.
In parts of their range they visit fish vendors and take scraps.
Prey is swallowed whole but the bones and fur cannot be digested so will be regurgitated later.
Grey herons are the most widespread heron in Europe with their range also covering Africa and Asia. Populations also exist in Australia but their origin is uncertain. A single record of the species exists from New Zealand.
Their range covers much of Europe, Asia and Africa.
Grey herons are considered habitat generalists. They will make their home in forests, grasslands, wetlands and any other habitat which provides shallow water and enough prey to eat.
Inland they make use of swamps, rivers, streams, marshes, flood plains and oxbows. They will also make use of man-made habitats such as rice-fields, reservoirs and other irrigated areas.
Along the coast they use mangroves, deltas, estuaries, mudflats and sand-spits.
Occasionally they will visit suburban backyards where they may steal fish out of ponds. Some people place decoy herons to discourage this but if anything this is thought to encourage more to visit.
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Breeding occurs in January or May in the northern areas of their range. In temperate areas they will breed during spring and summer while in Africa and the tropics breeding can occur year round with this event concentrated during the rains.
To breed successfully they require four months of warm weather.
Males will call call to advertise their presence to females. They will also point their bill upwards and stretch their wings to initiate preening.
Nesting colonies may include thousands of pairs though some choose to nest singly.
Their nest is formed from sticks and used for multiple years. Often it is located high in a tree though it may be on the ground or a cliff edge.
In to the nest they will deposit between 1 and 10 eggs. Only 1 brood is raised each year. These eggs are incubated for between 25 and 26 days. If this brood is unsuccessful they may lay a second.
These chicks are fledged within 45 and 55 days of hatching. Hatchlings may cannibalize their nest mates. The fledglings do not become independent till 9 or 10 weeks old.
Both the male and female are involved in providing care to the young. Parents begin by feeding the chicks directly but eventually regurgitate food in to the nest and all the chicks compete for this.
Juveniles can be distinguished from adults as they have a tatty looking appearance to their plumage.
Sexual maturity is reached between 2 and 3 years old.
Populations in the palearctic region will migrate after the breeding season in September or October and return in February. In the south of their range the populations remain in one place year round.
Feeding tends to be undertaken singly. Where food is abundant groups of them may congregate. It may occur anytime of the day or night.
In flight they tuck the head against the body and take slow wing beats.
During cold weather these birds will sleep longer each day.
A range of vocalizations are produced by the grey heron. They will also clap their bills together during mating or to greet another.
Predators and Threats
Foxes are the main threat to adult grey herons while the eggs are hunted by birds such as crows.
Previously the species has faced heavy persecution as they feed on fish which were viewed as important to local fisherman. This would lead to persecution through shooting, drowning or poisoning. They may also be hunted for the bushmeat trade.
Habitat alteration is an emerging threat across their range with timber hunting removing their nesting sites.
Virus outbreaks such as avian influenza and botulism have reduced their populations and future outbreaks pose an ongoing risk.
Previously roast heron was considered a delicacy in parts of their range though this is now uncommon.
I, Luc Viatour, CC BY-SA 3.0 <http://creativecommons.org/licenses/by-sa/3.0/>, via Wikimedia Commons
Basile Morin, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0>, via Wikimedia Commons
Middle Two and Bottom
Charles J. Sharp, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0>, via Wikimedia Commons
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