The Basics
Shoebill storks (Balaeniceps rex) are large, broad birds found in swamps and wetlands of Central and East Africa. It has a large body, huge wings, and a shoe-shaped bill. There is also some evidence that this prehistoric-looking bird is related to the now-extinct dinosaurs!
Their plumage consists of a dark grey, blue-grey, or slate color with a white belly. Its piercing yellow or white/grey eyes are piercing and piercing. Their wings can span up to eight feet, which they use for soaring.
The bird prefers papaya swamps, where water is flowing slowly towards a lake in the overspill areas. Fish are the primary food source for shoebill storks in this area.
Although Shoebill storks are diurnal, they will hunt at night if the moonlight is bright enough. In addition to fish, they also prey on water snakes, frogs, monitor lizards, and young turtles. Even baby crocodiles have been eaten by them!
In or near water, these birds can be found. Using plant material from the surrounding area, they even build their nests on top of floating vegetation. A nest is usually located in the deeper parts of a swamp, where the tall grasses and dense vegetation provide cover from predators.
It takes three to four years for a shoebill stork to reach sexual maturity. Their parental responsibilities are shared by monogamous birds. Two to three eggs are laid by the female, and they are incubated for 30 days. Using their feet or their bills, both parents will turn the eggs frequently.
The shoebill chick has a wide gape and is covered in silvery-grey down. These birds are known for their large bills, but they don’t show them until a month old. When the chicks are born, their parents feed them mashed up food. After a month, the parents start leaving prey items in the nest for the young birds to swallow. Chicks are independent by 125 days after flinging.
Interesting Insights from the Shoebill Stork!
The shoebill stork has been known to humans for a very long time. As far back as ancient Egypt, they were described in writing. The fact that we know relatively little about them compared to other species is surprising. Nevertheless, what we do know demonstrates some amazing biological principles!
Shoe-shaped Bill
A bird’s beak is designed to eat certain types of food and gives a lot of insight into what the primary food source is. A shoebill bird has a large bill shaped like a shoe that is an adaptation for catching and holding large, slippery fish. Its large bill measures 7.8 – 9.5 inches (20 – 24 cm) in length and 4 – 4.8 inches (10 – 12 cm) in width. It also has a razor-sharp, curved hook at the end for spearing prey.
These birds strike their prey with a unique technique called a ‘collapse.’ They stand motionless in the water, looking for food. When birds spot their prey, they lunge or fall forward onto it with their wings spread. After diving down, the bird ambushes its prey with its bill first.
In order to decapitate its prey, the shoebill bird holds up its head and grinds the sharp edges of its bill together. Water and vegetation that were absorbed along with the prey item spill out of the bill’s edges.
Urohidrosis
Shoebills, like pelicans and other storks, practice urohidrosis to keep cool. Urohidrosis is a cooling method, much like sweating, that enables the bird to cool down. Shoebill storks will defecate on their legs to lower their body temperature.
The liquid waste that these birds excrete from there cloaca is a mixture of feces and urine. The waste covers the birds’ legs, and as it evaporates, it cools the birds’ skin, much like sweat evaporating cools down our skin.
Unlike sweat, this method of cooling also involves a preventative measure. The evaporating liquid leaves behind a white, powdery substance that can reflect sunlight and prevent the legs from getting warm in the first place. How amazing is that!
Siblicide
An animal’s primary goal is to survive and pass on their genes, and there are several examples of how animals do this in nature. The mechanisms that birds use can range from focusing their energy on a small clutch of eggs, or having a large brood to increase the probability of survival.
Some birds are monogamous and work as a team to raise their chicks, while others are polygamous or promiscuous and prefer to mate with as many partners as possible.
Once fascinating yet grim example of animal survival is that of siblicide. Siblicide is when one of the offspring kills its sibling. There are several examples of birds that practice this behavior, including egrets, herons, pelicans, boobies, and shoebill storks.
Shoebill storks eggs hatch asynchronously. The first chick to hatch has no siblings to fight with over food, so it is well fed and develops quickly. When the second chick hatches, the parents do not make an effort to distribute food equally, and so it competes with its elder, well-developed sibling. The elder chick will bully and batter its sibling, and often the youngest chick will die due to its wounds or from starvation.
By focusing on the strongest chick, the parents increase the chances of at least one of their offspring reaching maturity and passing on its genes. From a survival point of view, it is better to have one healthy chick than several that are weak and unlikely to survive.
You may be wondering why the birds choose to lay more than one egg if only one chick is going to survive. The second and sometimes third egg is more like an insurance policy. If the first egg is infertile or lost to predation, the adults are still able to produce offspring. If food is plentiful, then there is limited aggression between the chicks, and it is more likely that all the chicks will fledge.