Welcome to Bird Brained Science’s first Amazing Species Profile!
For my first profile, I thought it only right to present my all-time favourite species of bird!
Give it up, for the fabulous secretary bird!
I had the pleasure of seeing these magnificent birds in South Africa during an undergraduate field trip and have been captivated by their unique physiology and behaviour ever since.
Taxonomy & Etymology
Along with other birds-of-prey such as hawks, eagles and vultures, the secretary bird resides in the taxonomic order Accipitriformes, but it is the only species within its family, Sagittaridae. As well as molecular evidence that separates this bird from other raptors, the secretary bird is thought to be the only extant bird-of-prey that has adapted to become a primarily terrestrial hunter. This is evidenced by their possession of the longest legs of any raptor with powerful upper leg muscles that can deliver kicks with deadly force to its most notorious prey, ssssssssssssssnakes.
The secretary bird’s latin name is Sagittarius serpentarius. ‘Sagittarius’ translates to ‘archer’, either a reference to the long arrow-like feathers in the crest or to the dexterous manner with which it hunts its prey. ‘Serpentarius’ translates, surprisingly, to ‘serpent’ which is likely to be attributed to the bird’s infamous nature of hunting snakes.
The common name, secretary bird, has a slightly more complicated history. For many years, it was thought that the bird acquired its name due to the long quills sprouting from the crown, resembling how a secretary’s quill used to rest behind the ear in more relevant times. Interestingly, in a comment in the Ibis by Professor Christopher Fry, it is noted that this perceived understanding of the name’s origin may be due a false etymological root and that the ‘secretary’ part of the name may in fact come from a French, and subsequent Anglican, corruption of the Arabic word ‘saqr-et-tair’, or ‘hunter-bird’. This would make sense as the first mention of secretary birds in European menageries occurred during 1770s, when it was thought the birds may have been traded through Egypt and North Africa by Arabs at that time.
As previously mentioned, the secretary bird is rather unique in its adaptations for terrestrial hunting and their body appears as a sort of eagle-headed crane-legged hybrid. These long legs grant the birds a height of up to 1.3 metres with a wingspan of approximately 2 metres centimetres, whilst the hooked bill adapted for tearing flesh makes the secretary bird a fearsome predator. Their plumage, a mixture of black, white and grey across the body, is adorned with elongated decorative feathers around the crest of the head and at the tail. The pure black ‘leggings’ that coat the tops of the legs give way to featherless lower legs and sharp talons for crushing and tearing at their prey.
Also, that face. Just look at that face. The transition outward from the beak between yellow and makes their faces light up like a sunset against their otherwise white facial plumage. If I was a snake, I’m sure would come to fear these colours like no other.
Ecology & Conservation
Secretary birds are endemic to sub-saharan Africa and can be found in most of the countries below this region everywhere from Senegal to South Africa. They primarily reside on the grasslands and savannahs, roosting atop Acacia trees.
As of 2011, they were reclassified on the IUCN Red List as ‘vulnerable’ due to a recent and rapid widespread decline in numbers, with the major threats stemming from habitat degradation and human disturbance, hunting and capture for trade. Hopefully, further research can enable us to predict what the future may hold for these wonderful creatures.
THIS is what secretary birds are known for. Their notorious snake hunting behaviour highlights how their physical adaptations have made them into efficient terrestrial hunters.
When a snake, or small mammal / lizard, is encountered during a hunt, the secretary bird can flush it out by stomping around and chasing it down by foot or by wing. It can then either strike with its beak, or as is more likely when dealing with a venomous snake, repeatedly and furiously stamp on the prey until it is rendered stunned or killed. Observers of this killing behaviour have noted that the secretary birds tend to aim for the upper neck or head of the snake, perhaps in an effort to snap the neck or crush the skull. Although they can easily swallow a whole snake, they may tear the snake apart with their talons before consuming it.
Here is footage of a secretary bird hunting a snake, wonderfully synchronised to music…
Although this video claims that a secretary bird’s diet is primarily snakes, they actually get most of their food energy from eating insects, small mammals and lizards. It is thought that snakes are more of an occasional treat than a dietary requirement, but can be regionally important for some populations.
The caption to this video also claims that secretary birds have no blood in their legs, which is ludicrous, but it is actually thought that the lower sections of secretary birds’ legs have developed much thicker scaly skin to reduce the risk of receiving a venomous bite. I haven’t been able to find much information regarding this trait, so there’s some interesting research to be looked into there!
That pretty much wraps it up for this Amazing Species Profile! Next time, I may stray a little further from the avian world! Thanks for reading!
— For more photos, the Arkive website has a great collection! —
Top Image Credit – Johannes Swanepoel