Species Details

Details of Grey Heron will be displayed below

Grey Heron   

Common Name: Grey Heron
Scientific Name: Ardea Cinerea
Local Name: Maakanaa
Dhivehi Name: މާކަނާ
Animalia  (Kingdom)
Chordata  (Plylum)
Aves  (Class)
Ardeidae  (Family)
Ardea   (Genus)

Grey Heron's description

The grey Heron, with an outstretched neck, is 84-102 cm in length. It has a long neck and strong pink-yellow bill. When flying, its neck is retracted (S.shaped) And its wings are bowed. Its plumage is grey above and whitish below. Adult grey herons have a white head with ablack supercilium and black crest. The grey heron feeds on fish, eels, turtle hatchlings, Small rodents and birds, molluscs, crustaceans, insects and plant matter.It catches prey by standing patiently for it to approach before striking rapdily either catching it in its bill or spearing it. It construct a flat nest of sticks in the crown of a tree. Both parents share incubation of eggs and take care of young.The grey heron breeds solitarily or in colonies called heronries. Successive generations often use the same breeding sites.

Grey Heron's facts

  • Herons are sociable birds when nesting, invariably nesting in long-established heronries.
  • Most heronries are in trees, with the majority of nests at least 25m above the ground. However, reed-bed heronries are not unusual, and they will also nest on cliffs, bushes, sometimes even on buildings of bridges.
  • It mainly eats fish, using three different hunting techniques: it can wait at one spot for prey to come within striking distance; it can walk carefully through shallow water before ambushing prey, or it just drops into the water from the air. 
  •  Grey herons egg-laying season is year-round, peaking from July-January.
  • It lays 1-4 eggs, which are incubated by both sexes for about 23-28 days.
  • The oldest chick is treated the best, as the younger siblings are often malnourished, in fact the youngest almost invariably dies before fledging. The chicks are brooded by both parents for roughly 18 days, and are still guarded 24/7 for another 11-12 days. They leave the nest at about 50 days old, becoming fully independent 10-20 days later.

Grey Heron's Behavior & Ecology

The grey heron has a slow flight, with its long neck retracted (S-shaped). This is characteristic of herons and bittern, and distinguishes them from storks,cranes, and spoonbills, which extend their necks. It flies with slow wing-beats and sometimes glides for short distances. It sometimes soars, circling to considerable heights, but not as often as the stork. In spring, and occasionally in autumn, birds may soar high above the heronry and chase each other, undertake aerial manoeuvres or swoop down towards the ground. The birds often perch in trees, but spend much time on the ground, striding about or standing still for long periods with an upright stance, often on a single leg.

Grey Heron's Feeding

The Grey Heron usually hunts solitarily, but in situations where food is more concentrated, birds may feed in loose aggregations or even mixed species flocks. If conditions are especially favourable, quite large feeding aggregations may form, particularly after the breeding season. Herons feeding alone defend their feeding territories. Defence may be vigorous, and killing of intruders is known. Aggression varies seasonally being most intense when young are being fed. Sites may be near to the colony site or as many as 38 km away. When available feeding areas are poor and/or more distant from the colony, adults use two or three feeding areas and are no longer territorial.

Depending on prey availability and distance, herons use three types of feeding sites

  • The individual defended feeding area composed of a single patch of about 20 h.
  • Individual nonterritorial feeding areas composed of 2 or 3 patches in poor habitats or in typical habitats more distant from the colony.
  • Neutral feeding sites used by many herons, where individual site appropriation is not possible. 

It mainly eats fish, using three different hunting techniques: it can wait at one spot for prey to come within striking distance; it can walk carefully through shallow water before ambushing prey, or it just drops into the water from the air. Once it catches something, it manipulates the first to a head-first position before swallowing it.

Grey Heron's Reproduction

This species breeds in colonies known as heronries, usually in high trees close to lakes, the seashore or other wetlands. Other sites are sometimes chosen, and these include low trees and bushes, bramble patches, Reed beds, heather clumps and cliff ledges. The same nest is used year after year until blown down; it starts as a small platform of sticks but expands into a bulky nest as more material is added in subsequent years. It may be lined with smaller twigs, strands of root or dead grasses, and in reed beds, it is built from dead reeds. The male usually collects the material while the female constructs the nest. Breeding activities take place between February and June. When a bird arrives at the nest, a greeting ceremony occurs in which each partner raises and lowers its wings and plumes. Courtship involves the male calling from the chosen nesting site. On the arrival of the female, both birds participate in a stretching ceremony, in which each bird extends its neck vertically before bringing it backwards and downwards with the bill remaining vertical, simultaneously flexing its legs, before returning to its normal stance. The snapping ceremony is another behaviour where the neck is extended forward, the head is lowered to the level of the feet and the mandibles are vigorously snapped together. This may be repeated twenty to forty times. When the pairing is settled, the birds may caress each other by attending to the other bird's plumage. The male may then offer the female a stick which she incorporates into the nest. At this, the male becomes excited, further preening the female and copulation takes place.

The clutch of eggs usually numbers three to five, though as few as two and as many as seven eggs have been recorded. The eggs have a matt surface and are greenish-blue, averaging 60 mm × 43 mm (2.36 in × 1.69 in). The eggs are normally laid at two-day intervals and incubation usually starts after the first or second egg has been laid. Both birds take part in incubation and the period lasts for about twenty-five days. Both parents bring food for the young. At first the chicks seize the adult's bill from the side and extract regurgitated food from it. Later the adult disgorges the food at the nest and the chicks squabble for possession. They fledge at seven to eight weeks. There is usually a single generation each year, but two broods have been recorded.

The oldest recorded bird lived for twenty-three years but the average life expectancy in the wild is about five years. Only about a third of juveniles survive into their second year, many falling victim to predation.

Grey Heron's Conservation

The IUCN red list currently classifies the grey Heron under least concern. It has suffered population decline in the past due to competition with fishermen and fish farmers. It is vulnerable to habitat loss and loss of breeding sites.

In Maldives it is illegal to catch or to pet.

Grey Heron's Relationship with Humans

Roast heron was once a specially-prized dish in Britain for special occasions such as state banquets. 

Incredible tourist attracting bird.

 

Grey Heron habitat

Behaviour Most Palearctic populations of this species are fully migratory, dispersing widely in September-October after the breeding season and returning to breeding grounds in February (Kushlan and Hancock 2005). Further south, populations tend to be sedentary or only partially migratory. Most migratory movements occur nocturnally, with birds moving in small parties or larger flocks of 200-250 (Brown et al. 1982). The species breeds January-May in the Palearctic Region, and in spring and summer in temperate areas, but mainly during the rains in Africa and the tropics(although here it may also breed in any month of the year) (Kushlan and Hancock 2005). It breeds in mixed colonies of hundreds or thousands of pairs (the largest colony in Europe is 800-1,300 pairs), although it may also nest solitarily or in small groups of 2-10 nests (Kushlan and Hancock 2005). The species is typically a solitary feeder but at abundant temporary food sources, or where available feeding areas are restricted, large congregations may occur (Snow and Perrins 1998, Kushlan and Hancock 2005). It feeds at any time day or night, but is most active at dawn or dusk, typically roosting communally or solitarily (Brown et al. 1982) during the middle of the day and at night (Kushlan and Hancock 2005) in trees and on cliffs, low rocks, islets or along shores (Brown et al. 1982). Habitat This species is a generalist in its habitat use, although shallow water, relatively large prey, and four or five months of ice-free breeding season are among the essential characteristics of its habitat (Kushlan and Hancock 2005). It occurs from sea-level up to 500 or even 1,000 m, occasionally breeding much higher (Snow and Perrins 1998) (2,000 m in Armenia, 3,500-4,000 m in Ladakh, north-west India), inhabits any kind of shallow water, either fresh, brackish or saline, both standing or flowing, and shows a preference for areas with trees as it is commonly an arboreal rooster and nester. Some degree of isolation and protection are also typical of places chosen for roosting and nesting (Kushlan and Hancock 2005). The species is found inland on broad rivers, narrow streams, lake shores, ornamental ponds, fish-ponds, marshes, flood-plains, reeds swamps, rice-fields and other irrigated areas (Brown et al. 1982, Snow and Perrins 1998, Kushlan and Hancock 2005), river oxbows, reservoirs, ditches, canals, sewage farms, inland deltas, and on islets and emerging rocks (Snow and Perrins 1998). On the coast the species also frequents deltas, salt-marshes, mangroves (Brown et al. 1982, Kushlan and Hancock 2005), estuaries, tidal mudflats, muddy and sandy shores, and sand-spits (Snow and Perrins 1998). Diet Its diet consists predominantly of fish and eels 10-25 cm long, as well as amphibians, crabs, molluscs, crustaceans, aquatic insects, snakes, small rodents, small birds (Brown et al. 1982, Snow and Perrins 1998, Kushlan and Hancock 2005) and plant matter (although this may be incidental,or only to aid in pellet formation) (Brown et al. 1982, Snow and Perrins 1998, Kushlan and Hancock 2005). Breeding site The nest is a stick platform that is often re-used over successive years (Kushlan and Hancock 2005), usually positioned high in a tall tree up to 50 m, but also on the ground or on cliff edges, in reedbeds or in bushes. In reed-beds nests may be built of reeds, and ground nests may be reduced to a slight scrape, ringed with small stones and debris (Snow and Perrins 1998). The species commonly nests in colonies, and nesting sites are typically situated 2-38 km (convenient flying distance) from preferred feeding areas (Kushlan and Hancock 2005).

Grey Heron threats

In Europe the species was heavily persecuted in the nineteenth century due to its consumption of fish, which resulted in competition with fishermen and fish farmers (Kushlan and Hancock 2005). Although killing at aquaculture farms has not reduced the global population so far (possibly because it is young birds that are mostly killed) (Kushlan and Hancock 2005), 800 herons are estimated to have died per year at Scottish fish-farms between 1984 and 1987 (Carss 1994, Kushlan and Hancock 2005) by being shot, drowned or poisoned by fish farmers (Carss 1994). Renewed hunting poses a threat to Bavarian populations by decreasing numbers to levels that inhibit recovery following severe winters (severe winters increase mortality rates for juveniles) (Kushlan and Hancock 2005). The species is vulnerable in Madagascar owing to its restricted range, exceedingly high levels of habitat alteration (from siltation and the need for agricultural land for rice and grazing) (Kushlan and Hafner 2000, Hafner and Kushlan 2002), hunting, and predation at nesting colonies (Kushlan and Hafner 2000, Kushlan and Hancock 2005). Timber harvesting is a threat throughout much of the species's range by removing trees used by nesting colonies and/or disturbing nearby colonies (Kushlan and Hancock 2005). The species is also susceptible to avian influenza (Melville and Shortridge 2006) and avian botulism (van Heerden 1974), so may be threatened by future outbreaks of these diseases.

Utilisation The species is hunted and traded at traditional medicine markets in Nigeria (Nikolaus 2001).

Grey Heron's status