Secretary bird

The secretary bird (Sagittarius serpentarius) gets its name from its crest of long plumes which resemble a clutch of quill pens stuck behind the ear of an old-fashioned clerk. It is a bird of prey within the order of Accipitriformes but it has been given its own family (Sagittariidae) and genus (Sagittarius) because of the differences between it and all other members of the order.

The secretary bird is a hawk that ranges throughout sub-Saharan Africa except for the tropical forests. It inhabits the plains and veldt, wandering large distances in search of food. It is thought to be partly migratory. 

Appearance

It is a large, long-legged bird, some 45 inches in length but standing up to four feet tall. Its wingspan is six and a half feet. It is the world’s largest diurnal bird of prey. The head is eagle-like, with a hooked bill. The plumage is mainly white, although the wings are grey and black, the face is red and the thighs are covered in dark grey feathers. The plumage of males and females is similar, although female secretary birds are slightly smaller (which is unusual for raptors) and have shorter plumes and tail feathers.

Behaviour

The secretary bird is renowned for killing and eating snakes, which is why it has the designation “serpentarius”. It hunts on foot, approaching its prey in a zigzag fashion and flapping its wings so as to confuse its victim. 

When a snake is encountered the secretary bird will thrust its wing towards the snake, so that this is where the snake will strike. As the wings contain no blood vessels, the secretary bird cannot be harmed, but this action by the snake makes it easy for the bird to hold the snake down with one foot and grab the back of its neck in the beak. If this does not kill the snake, the secretary bird will fly aloft and drop the snake on to the hard ground in the manner of a seabird dropping a crab or clam to break its shell.

Apart from snakes, secretary birds will take other reptiles, small mammals, large insects such as locusts, and the eggs and young of other birds. Some African farmers encourage secretary birds to patrol their land so as to keep it clear of snakes, but they must also take care to protect their own domestic fowl.

Secretary birds usually hunt alone, but a pair may hunt as much as half a mile apart, calling to each other with loud reedy calls that can easily carry for such a distance. Groups of secretary birds are sometimes seen when a grass fire has driven small animals in one direction, thus providing easy prey.

Breeding

Secretary birds are believed to mate for life. The pair will build a rough nest of sticks in a bush or tree and will reuse it year after year, adding new material so that nests can grow to quite large sizes over time, perhaps as much as six feet across. The usual clutch is two eggs, which take around seven weeks to hatch. Both partners share the duties of incubation and of feeding the young, which is done by regurgitating half-digested food. The young birds take about two months before being fully fledged.

© John Welford