Scopidae Hamerkop
Version: 1.0 — Published March 4, 2020
Introduction
Seen near their massive nests, the crow-sized Hamerkops seem awkwardly out of scale. Single pairs build these stick nests, which are so substantial that they provide resting place and shelter for many other animals. This species is revered in many local cultures for setting a good example with its dedicated parenting. A modest brown bird, it walks and swallows like a heron, though it lacks the herons’ long neck for making more distant captures. The Hamerkop’s long tail and broad wings give it a rather heavy-tailed look, slightly balanced by its crested head. That crest, swept back like no other, together with the long triangular bill, really does give the head a hammer-like shape.
Habitat
Hamerkops are primarily found in open country near water (streams, rivers, waterholes, etc.), and most often near trees, their preferred nesting substrate.
Diet and Foraging
With its laterally compressed bill, the Hamerkop is specialized for feeding on small fish and frogs, being especially fond of clawed frogs (Xenopus). It is also known to feed on crustaceans, worms, and occasionally small birds and mammals. Though usually capturing prey heron-like from the shore, Hamerkops sometimes fly low over the water, scooping up tadpoles or small fish from the surface while in flight.
Breeding
Hamerkops are monogamous with biparental care. There is some evidence that other adults will assist the breeding pair with nest construction, although it is unclear what, if any, role these helpers have in the later breeding attempt. Hamerkops build the largest nest of any bird, a massive structure built mostly of sticks held together with mud, usually placed in a tree and often adorned with objects such as bones and scraps of fabric. Starting with a platform, the walls are then built up, and a roof, often very thick, over this central chamber tops off the construction. The only entrance hole is located on the underside of the nest and leads to the nest chamber, which is lined with mud and leaves. Females typically lay 3 to 6 eggs. Both male and female Hamerkops are active throughout much of the year in building nests, which they roost in when they are not nesting. Single pairs may build up to a handful of nests in a single year, and they have up to a dozen that they can visit at any given time. Nest predation rates are not as low as one might suspect, and multiple nests in a pair’s territory may help to reduce predation risk at any given nest. Both male and female incubate, though the female may do more than her share, and both parents feed the chicks. The downy chicks hatch, asynchronously, after an incubation period of about a month, and they remain in the nest until they fledge at about six weeks of age.
Conservation Status
The Hamerkop faces no immediate conservation concerns.
Systematics History
The Hamerkop is in Pelecaniformes, within which it is most likely sister to the Shoebill. These two taken together appear to be sister to the pelicans (van Tuinen et al. 2001, Mayr 2003, Hackett et al. 2008, Mayr 2011).
Conservation Status
Least Concern |
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Near Threatened |
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Vulnerable |
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Endangered |
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Critically Endangered |
0%
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Extinct in the Wild |
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Extinct |
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Not Evaluated |
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Data Deficient |
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Unknown |
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Data provided by IUCN (2023) Red List. More information