Black Heron

Egretta ardesiaca

SUBFAMILY

Ardeinae

TAXONOMY

Ardea ardesiaca Wagler, 1827, Senegambia. Monotypic.

OTHER COMMON NAMES

French: Aigrette ardoisée; German: Glockenreiher; Spanish: Garceta Azabache, Garceta Gorgirroja.

PHYSICAL CHARACTERISTICS

Medium-sized (17–26 in [42.5–66 cm]), all-black plumaged African heron with yellow feet, usually seen feeding in open shallow water.

DISTRIBUTION

Occurs in Madagascar and Africa south of the Sahara.

HABITAT

Prefers shallow open waters, especially margins of fresh water lakes and ponds. Also uses marshes, river edges, rice fields, and seasonally flooded grasslands. Along the coast it feeds along

tidal rivers and creeks, mangroves, alkaline lakes, and tidal flats.

BEHAVIOR

Exhibits distinctive feeding behavior called canopy feeding. It spreads its wings over its head in a full umbrella, with the tips of its primaries touching the water and erect nape plumes completing the canopy. The heron forms the canopy above the potential prey over the course of a few steps. It peers under the canopy for a few seconds, perhaps also stirring with its feet. The heron then moves on a few steps to form another canopy, usually within a few more seconds. It frequently pauses to shake itself.

FEEDING ECOLOGY AND DIET

The functioning of the canopy feeding behavior remains unclear, although the canopy reduces reflection and provides better visibility in addition to obscuring the silhouette of the heron. Fish are likely attracted to the shadow or are attracted to or flee the foot stirring. Some resident black herons feed solitarily in well-defended feeding territories. They also feed in groups of up to 50 individuals, with over 200 being reported. Feeds by day, especially around dusk. Roosts communally at night and, on the coast, at high tides. Eats small fish, but also takes aquatic insects and crustaceans.

REPRODUCTIVE BIOLOGY

The nest is a solid structure of twigs placed over water in trees, bushes, and reed beds. Nests at the start of the rainy season, in single or mixed-species colonies that may number in the hundreds. Eggs are dark blue and the clutch is two to four eggs.

CONSERVATION STATUS

Threatened on Madagascar, where human interference and habitat change have led to massive population reductions. Elsewhere, the heron is patchily distributed but not uncommon. Its greatest threats are human disturbance, predation at nest sites, and threats to aquatic habitats.

SIGNIFICANCE TO HUMANS

The distinctive feeding behavior and its feeding in open areas makes it easily noticed where it occurs.

For the steamship, see SS Black Heron.

Black Heron
Conservation status
Least Concern (IUCN 3.1)
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Aves Order: Ciconiiformes (disputed) Family: Ardeidae Genus: Egretta Species: E. ardesiaca
Binomial name
Egretta ardesiaca (Wagler, 1827)

The Black Heron, Egretta ardesiaca, also known as the Black Egret, is an African heron. It is a medium-sized (42.5–66 cm in height), black-plumaged heron with yellow legs and feet. It is found south of the Sahara Desert, including Madagascar, and prefers shallow open waters, such as the edges of freshwater lakes and ponds. It may also be found in marshes, river edges, rice fields, and seasonally flooded grasslands. In coastal areas, it may be found feeding along tidal rivers and creeks, alkaline lakes, and tidal flats. Its breeding range is between Senegal and Sudan and to the south. It is found mainly on the eastern half of the continent.

The Black Heron has an interesting hunting method called canopy feeding — it uses its wings like an umbrella, and uses the shade it creates to attract fish. This technique was well documented on episode 5 of the BBC's The Life of Birds. Some Black Herons feed solitarily, while others feed in groups of up to 50 individuals, 200 being the highest number reported. The Black Heron feeds by day but especially prefers the time around sunset. It roosts communally at night, and coastal flocks roost at high tide. The primary food of the Black Heron is small fish, but it will also eat aquatic insects, crustaceans and amphibians.

The nest of the Black Heron is constructed of twigs placed over water in trees, bushes, and reed beds, forming a solid structure. The heron nests at the beginning of the rainy season, in single or mixed-species colonies that may number in the hundreds. The eggs are dark blue and the clutch is two to four eggs.

References

• BirdLife International (2008). Egretta ardesiaca. 2008 IUCN Red List of Threatened Species. IUCN 2008. Retrieved on 9 February 2009. Database entry includes justification for why this species is of least concern.
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