This week’s animal is a bird that my mum has become enamoured with since she first learnt about it and it is easy to see why. Looking almost prehistoric with an ability to stay almost deathly the shoebill is a strange but fascinating bird too weird to make up.
Taxonomy and Evolution
It is unsurprising that shoebills are not only the only member of their genus, scientific name Balaeniceps rex, but also their family. Their closest living relative is another strange bird called the hamerkop. For a while where shoebills fit in the bird family tree had been up in the air with zoologists historically placing them in the order that storks belong to, of course they look and act like storks. However, from the 1990s zoologists commented that their eggs resemble the eggs of a different order of birds called Pelecaniformes – the order that pelicans belong to and also herons, ibises, and spoonbills. DNA tests done in 2003 and later 2008 confirmed that these strange birds were indeed a member of Pelecaniforma. We do have some fossil relatives of shoebills known from a few fossils – Goliathia from Egypt 30 million years ago and Paludiavis from Pakistan around 8 million years ago.
Biology and Behaviour
Standing 1 to 1.5 metres (4-5 feet) tall, with long gangly legs and salty-grey feathers shoebills are a strange looking bird. Males are larger than females. The most iconic thing about them has to be their bill. As you can tell it looks like a clog that ends with a hook, something that helps them catch prey. These bills are incredibly strong being able to decapitate fish when they plunge into the water, and the thickness in the bill allows them to communicate. Although normally silent shoebills will clatter their bill to make loud noises in order to alert their chicks or partners. The YouTube video below compares it to the sound of a machine gun.
Shoebills are mostly solitary, only coming together to mate, build a nest, and raise a chick. Active during the day they are seen wading through the water, their bill pointed downwards, looking for food. While wading they can be graceful but going for food is far from graceful. They effectively collapse on the spotted prey with them ideally catching it in the giant bill. Imprecise, detritus and vegetation get caught in the bill which the shoebill shakes out, however, this also serves as a purpose to kill the prey caught by the shoebill. Much like herons and storks shoebills have good eyesight in order to spot their prey, something which limits them to daytime wading (as mentioned above).
Shoebills form monogamous pairs during the breeding season where together they work to make a nest and forge a territory. Aggressive to rival pairs their territory covers a 3 square kilometre range which they protect via hard bill snaps and deep calls. The birds trample a 3 metre diameter area which in the centre they build a floating nest out of aquatic vegetation. In that nest they lay two eggs around the start of the dry season which hatch within 30 days. Shoebills take care of their chicks for a very long time, exceeding 90 days, although the young birds are unable to fly upon leaving their parents. Albeit shoebills are non-migratory so flying is not as essential as compared to other birds. Shoebill parental instincts only extend to the strongest chick. When one chick starts bullying the other the parents will give all their attention to that chick leaving the smaller chick to die. Other than that the parents are devoted, even scooping up water in their bills which they drop on the chicks to cool them down. Parents also make deep calls to alert their chicks, or potentially drive off threats.
Distribution and Habitat
Shoebills are found in east Africa stretching from northern Zambia, eastern Democratic Republic of the Congo, western Tanzania and Kenya, across Uganda, and finally up to South Sudan and southern Ethiopia. As expected from what we’ve discussed already shoebills are found in wetlands and riverbanks where they can wade looking for food. Archaeological evidence suggests that shoebills had a wider distribution being depicted in ancient Algerian and Egyptian art. Tens of thousands of years ago North Africa was far wetter which would have provided the ideal habitat for shoebills before the Sahara underwent desertification.
Diet and Threats
Shoebills are carnivorous with a particular preference for fish, namely catfish and lungfish. They prefer poorly oxygenated water as this forces fish to the surface to get oxygen making it easier for them to hunt. Other than fish they also eat frogs, baby crocodiles, water snakes, and snails. Adult shoebills do not really have predators, although a crocodile would not say no to chomping down on one. Chicks and eggs are at greater risk with monitor lizards, monkeys, and storks going after them. Shoebills have been spotted hissing and snapping at marabou storks which normally patrol wetlands and grasslands for smaller animals to snap up. This indicates that shoebills might recognise marabou storks as threats to their chicks.
Conservation and Threats
It is another sad case that these strange birds are endangered, being rated as ‘Vulnerable’ by the IUCN. The main threat to them is habitat destruction as wetlands are drained for agriculture and dam construction. Relying on these wetlands for food and building nests the destruction of this habitat leaves them nowhere to go. Furthermore, shoebills are known to entirely abandon their nests if overly disturbed leaving chicks to die. Poaching has also hurt their numbers, mainly as collectors in wealthier countries offering large amounts of money to impoverished communities for smuggling birds for private zoos. Finally, there is the issue of climate change. For east Africa the climate catastrophe is already here causing wetlands to vanish as rising temperatures lead to desertification. Once again the wealthier countries have the responsibility to act. Much of the expansion into their habitat is to make room for farming to fit the global north; private collections demand the birds; and we in the north are consuming resources destroying the south. By changing how we interact with nature is the only way to save shoebills.
Bibliography:
- BirdLife International, ‘Balaeniceps rex (Shoebill)’, IUCN Red List, (13/08/2018), [Accessed 19/06/2024]
- Angie Steffen, ‘Balaeniceps rex‘, Animal Diversity Web, (2007), [Accessed 24/06/2024]
- Gerald Mayr, ‘The phylogenetic affinities of the Shoebill (Balaeniceps rex)’, Journal of Ornithology, 144, (2003), 157-175
- Acácio Marta, Mullers Ralf H E, Franco Aldina, Willems, Frank J, and Amar Arjun, ‘Changes in surface water drive the movements of Shoebills’, Scientific Reports, 11:1, (2021)
- Ralf Mullers and Arjun Amar, ‘Parental Nesting Behavior, Chick Growth and Breeding Success of Shoebills (Balaeniceps rex) in the Bangweulu Wetlands, Zambia’, Waterbirds: The International Journal of Waterbird Biology, 38:1, (2015), 1-9
- Don Wilson, (ed.), Wildlife of the World, (New York, NY: DK, 2015)
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