BIRD OF THE MONTH; by Doreen McColaugh
Bird of the Month by Doreen McColaugh
The Marabou Stork, Leptoptilos crumenifer, is the largest of the 8 species of storks that have been recorded in Botswana ( Abdim’s, African Openbill, Black, Marabou, Saddle-billed, White, Wooly-necked and Yellow-billed Storks) and is even the largest of all the world’s 20 species of storks. It stands up to 152cm and can weigh 9 kg. With a wingspan of 3 – 4 m it is known as the land bird that has the second largest wingspan – the California Condor holds the wingspan record. The Marabou Stork is also known for being “the world’s ugliest bird”. Although considered ugly by many due to its reddish bald head (most often bald although it sometimes has a tuft of white hair-like feathers on top of its head) and with a bare neck, huge bill, and the large, pink gular sac that hangs from its throat, long black legs that are often seen white as it defecates on its legs to keep cool, and the way It stalks or strides around - it is still an interesting bird. The obvious gular sac is a unique large, pink to orange, 25 cm long sausage-shaped pouch that is an air sac functioning as a cooling mechanism that can be inflated and also used to show dominance over a food source, a nesting site or a perch. There is another red air sac at the base of the back of its long neck that can also be inflated. The second part of its scientific name, crumenifer, is based on the appearance of the pendulous front air sac and means “çarrier of a pouch for money”. Sometimes people mistake the gular sac for an external crop where the Marabou Stork would store food, which is not the case. The wings and the back are dark grey to black and the underparts are white. The white feathers where the wings join the body and under the tail are short, soft and fluffy. When the Marabou has its wings folded against its body as it is standing upright and walking around slowly it gives the appearance from the back as wearing a dark cloak, also giving it the name of the ”Undertaker Bird”. Certain Marabou Stork feathers, in times past, were collected to decorate hats and various clothes and even to make scarves.
Although there are reports of the Marabou being aggressive against people, especially children; that is not always the case. It also is considered a social bird that interacts with people and my husband and I experienced that when we lived in Kenya. There was a hotel we frequented on the shores of Lake Naivasha that had a large outdoor eating area with many tables at the edge of the lake. There were several Marabou Storks that would slowly stalk through the dining area and would help themselves to food from your plate if it interested them. Due to their size and demeanour you didn’t resist as perhaps if you did they could become aggressive, although we never witnessed that. It was always an interesting experience!
Marabou Storks are primarily scavengers but will eat just about anything and will gather in large numbers at floodplain pools that are drying up and catch the stranded fish. As a small dam on the southern side of Mokolodi Nature Reserve was drying up over 100 Marabous were seen there one day. They must have cleaned out most of the fish as the next day most had moved on and only 3 Marabous remained. One of the best places to see Marabous up close in Botswana is at rubbish dumps where they can gather in large numbers. They also compete with vultures at kills. They do not have a raptor’s type of bill to tear open a carcass but use their large bill to go inside a carcass and pull out large pieces of meat and reportedly can swallow a chunk of meat that weighs a kilo. But often at a kill they might just pick up scraps dropped by vultures. They are known to feed on outbreaks of certain insects as well as frogs, snakes, rats, crocodile eggs and baby crocs and even feed on other birds’ eggs and raid quelea flocks that gather in huge numbers. They can decimate a colony of flamingo chicks. Although most stork species depend on water habitats and food found there Marabou Storks are less dependent on that habitat and will also be found in savannah grasslands as well as at areas of shallow water where the water is drying up. There they feast on their prey that is easy to catch. They are also attracted to bush fires where they feed on the fleeing insects and small animals.
The male and the female look just alike although there is sexual dimorphism in size with the male being noticeably larger than the female. It takes approximately 4 years to reach maturity and the juveniles can be recognized by being brown in colour with smaller bills. Once mature they seek mates that they normally stay with for life. Although they may breed singly, the largest communal breeding site in Southern Africa is in the Okavango Delta where hundreds can be seen in the winter breeding season from May to August with June and July usually good times to see them. They may nest among other stork species and even herons and cormorants. However, their large platform nests are always built in the tops of the largest trees that are usually surrounded by water. The platform of the nest which is built of sticks may be a metre in diameter and fairly thick but it has a shallow cup-like structure on top that they line with grass where the 2-3 eggs are laid. Incubation is shared by the monogamous pair for approximately 30 days. Both parents also care for the nestlings over a period of 4 months, however usually only one chick will survive to the fledging stage. Once mature, a Marabou Stork can live as long as 25 years in the wild but has been recorded living as long as 41 years in captivity.
The name Marabou comes from Arabic, meaning ‘quiet’ or ‘hermit-like’ but although mostly quiet and thought to not have a voice box Marabou Storks do make a variety of mooing and grunting sounds along with a lot of bill clattering. They really aren’t hermit-like as they do gather in large groups and have been seen gathering in the thousands in summer in the Kalahari in Botswana. After breeding they move around a lot and can be seen using air thermals to travel large distances. An adaptation to help such a large bird to fly, its leg and toe bones are hollow. When flying, they unlike other storks, bend their neck to keep it close to their body and not outstretched in front of them. Although a Marabou can travel to great heights and vast distances using thermals once it is airborne, it is considered a relative poor flyer in that it must take a laborious short run with its head and neck lowered to be able to take off and is dependent on thermals. On days with no thermals it might just remain on its roost all day rather than try to fly about. Marabous are called lazy birds as they are not early risers and call it a day a couple of hours before other birds do. They are reported to just stand around a lot not doing much of anything.
Recently a group of over 300 Marabou Storks was seen at Gaborone Game Reserve. If you miss a sighting such as the hundreds at Gaborone Game Reserve, rubbish dumps around the country or disposal sites such as the one on the road to Lobatse are good places to see Marabous up close and to be able to observe their behaviour. Marabou Storks, like vultures, help to keep environments clean and control diseases because they feed on rotting carrion and also consume edible refuse in garbage dumps. Don’t miss this amazing bird!
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