Bio Facts: Heron, Goliath
Africa south of the Sahara; Pakistan; Syria; Iraq
Shallow water of rivers & lakes, both salt and fresh; marshes & swamps; tidal estuaries; reefs, mangrove creeks.
Size 4 to 5 feet (1.2 to 1.5 m) tall; weight averages 9.5 to 9.6 lbs. (4.31 to 4.345 kg). Our male has weighed up to 11 lbs. (5kg), and he still feels thin. Males are usually larger than females. Voice is a loud croak, grunt or hiss. Many are silent outside the breeding season, but in colonies of breeding birds, the general hubbub of sound is quite loud. Coloration is a mixture of gray and chestnut, with some black streaking on the white front of the neck. Males and females look alike. The bill is black, and almost yellow on the keel. The legs are black. The eyes are yellow.
In the wild, they eat eels, crustaceans, large fish, amphibians, reptiles, small mammals, birds and insects. In the Zoo, they are fed fish, mice, chicks, and bird of prey meat, a scientifically, commercially prepared bird of prey diet.
These birds are extremely shy and wary of humans. The birds are fairly sedentary and research indicates they do not migrate. These large herons have strong bills. When they fly, they tuck in their long necks and let their long legs trail out behind them, but not on the horizontal as other herons. Legs in flight are held at an angle below the body. Their wing beat is slow, and they are capable of flying very long distances.
These birds tend to be solitary hunters. They hunt by waiting and watching patiently, or by walking slowly forward with the head held horizontally and the neck characteristically crooked, ready for a lightning thrust.
Long plumes on the head, neck, breast and back develop well before the breeding season, assuming their most luxurious color, length and texture when courtship commences. The courtship ritual is unknown. This species is a monogamous, solitary breeder that occasionally forms loose colonies, sometimes with other species.
The breeding season seems generally to coincide with the start of the rainy season. The nest is about 3 feet in diameter, and is usually placed on flattened ledges 2 or 3 feet above the water. Clutches average between 2 to 4 eggs. Incubation begins with the first egg laid, and both parents share in incubating the eggs (24 – 30 days). Sibling rivalry is very intense and siblicide has been observed. Siblicide is an aggressive act or series of aggressive acts towards a sibling that results in the death of that sibling. Siblicide is not the death of a sibling due to natural selection via scramble competition. At first glance this may seem like a maladaptive strategy, but siblicide can benefit both the parents and the offspring. This behavior benefits the parents because their progeny that are “best able to provide a return on parental investment” will survive (Alcock, 1998). Offspring benefit because they will receive a greater proportion of the resources provided by the parents .
When nesting is complete the young of the year fly off in all directions, although northern birds do no remain long in their summer breeding areas before moving further south in search for food.
Its height is an adaptation. This long-legged bird wades into deeper waters to get large fish that other birds cannot handle. By doing so, it reduces its competition for food with other similar birds.
The Goliath Heron is the largest living heron at 4.9 feet (1.5 m) tall.
Herons lack oil glands that are so prominent in other kinds of water birds. Instead, “powder down”, produced when down feather barbs start to break down, is the substance used for insulation and waterproofing.
The oldest heron ever recorded lived over 23 years.
This heron is susceptible to kleptoparasitism (the habitual stealing of food from another organism) by fish eagles or wood storks in our collection.
The name “heron” is related to the Greek word “krizein.” which means, “to cry out or shriek.”
Not endangered, but regional populations are relatively small. Exposure to pesticide residue in prey may be a threat to its survival.