Birds
Marabou Stork
Leptoptilos crumenifer · also called marabou stork, undertaker bird
The marabou stork is not a handsome bird. It is bald, hunched, scab-headed, and often streaked white with its own droppings, and it makes a living around carcasses and rubbish dumps. It is also one of the largest flying birds on Earth, an important scavenger, and — seen soaring on a thermal — genuinely impressive.
Overview
Marabou storks live across sub-Saharan Africa, in open savanna, grassland, wetlands, and lake shores, and increasingly in towns and cities, wherever there is food and large trees or cliffs for their colonial nests. They are social, gathering in flocks at feeding sites and roosts, and they soar for hours on thermals, frequently in the company of vultures.
A vulture in stork’s clothing
Although it is a true stork, the marabou has converged on the vulture lifestyle. Its head and neck are bald, keeping them clean when it plunges into a carcass; it follows vultures to kills and muscles in with its huge bill; and it soars on broad wings to cover ground looking for food. It also hunts and scavenges widely — fish, frogs, insects, small mammals, other birds’ eggs and chicks, and flamingos at their breeding lakes.
Size
A marabou stands up to 1.5 metres tall and has a wingspan of 2.6–3.7 metres, among the largest of any flying land bird, comparable to the Andean condor.
Keeping cool by fouling its legs
The marabou practises urohidrosis — deliberately excreting onto its own legs. As the fluid evaporates it cools the blood in the legs, a heat-shedding trick for a bird that stands around in the sun. It is why a marabou’s legs usually look white.
Living with people
The marabou has adapted extremely well to humans. Flocks patrol rubbish dumps, markets, and abattoirs across Africa, and by consuming carrion and food waste they provide real sanitation — while also fouling the towns they roost in and preying heavily on other birds’ colonies.
Status
The marabou stork is Least Concern, common, and possibly increasing as it exploits human food waste.
Marabou Stork: common questions
Why is the marabou stork called the "undertaker bird"?
From a distance, especially seen from behind, a marabou stork looks like a stooped figure in a dark cloak with a bald pale head — the dark grey folded wings hang like a coat over the pale underparts and the white, excrement-coated legs. Combined with its habit of standing motionless near dead animals waiting to feed, and its slow, stalking walk, the impression is of a funeral director or a hooded mourner. The name is common across English-speaking Africa.
How big is a marabou stork?
It stands up to about 1.5 metres tall, weighs up to 9 kilograms, and has a wingspan usually given as 2.6 to 3.2 metres, with exceptional individuals claimed at up to 3.7 metres. That puts it in the small group of land birds — with the Andean condor and a couple of others — that have the largest wingspans of any bird capable of flight (some seabirds like the wandering albatross have longer, narrower wings). Marabou storks soar effortlessly on thermals, often alongside vultures, using very little energy to stay aloft for hours.
Does the marabou stork really defecate on its own legs on purpose?
Yes. The behaviour is called urohidrosis, and several birds do it, including New World vultures and some storks. The bird excretes a watery mix of urine and faeces onto its legs, and as the liquid evaporates it draws heat away, cooling the blood flowing through the legs in the same way sweating cools a mammal. In the hot, open habitats where marabou storks feed and stand around for long periods, this is a useful way to shed heat. It is also why the legs of a marabou usually look chalky white rather than the dark grey they actually are.
Is the marabou stork dangerous or a pest?
It is not dangerous to people, though a bird this size with a heavy 35-centimetre bill can defend itself and will readily rob a picnic or a market stall. It is more of a nuisance-and-benefit than a pest. On the benefit side it is a major scavenger, clearing carcasses and edible rubbish that would otherwise breed disease, and around African towns marabou flocks do real sanitation work. On the downside it raids other birds' colonies — it is a significant predator of flamingo eggs, chicks, and even weakened adults — and large numbers roosting in a town foul streets and buildings.