South Africa is home to approximately 850 bird species of which 50 are found nowhere else on earth. Bird watching is extremely rewarding and is a great additional activity to any bush or 4×4 outing. For anyone interested in photography, birds are excellent – if somewhat flighty – subjects (pun intended!).
Being so spoilt for choice makes deciding which ones to write about something of a challenge. However, the Bee-eaters are in my ‘top five; of beautiful birds, the others being Rollers, Sunbirds, Kingfishers and the African Green Pigeon. Bee-eaters are skilled in flight and excellent hunters. Prey – predominantly in the form of bees as their name suggests – is caught in flight and then taken back to a perch to be beaten. The tail end of the bee is rubbed against the perch until the sting and venom are discharged. The epitome of ‘fast food’ consumers, bee-eaters complete the entire process of immobilising and de-venoming in 5-10 seconds. They then toss the insect into their mouth and swallow. Any parts of the prey that are indigestible are regurgitated in the form of pellets.
Whilst we tend to associate sociality with mammals, birds such as the White-fronted Bee-eater are strongly gregarious and have a complex social organisation. A breeding unit comprising one pair and one to five helpers joins up with another breeding unit of similar structure. Together they comprise a ‘clan’ that will actively defend their feeding territory. These clans remain stable over long periods of time and will move between their feeding territory and the colony in which they reside.
The Rollers obtain their name from a unique courtship behaviour practised by the male. In this feat of aerobatics, he will climb to approximately 20-50m at which time he tips forward and dives earthwards with closed wings. In the latter part of the dive – which may be repeated multiple times – he rolls from side to side, hence the common name of Roller. All are stunningly beautiful birds with various shades of green, blue, purple and cinnamon in their plumage. Unfortunately, their voice does not emulate their beauty, being a harsh, raucous call which is most frequently heard during the breeding season. They are hole nesters but do not excavate their own holes, preferring natural tree cavities or large woodpecker holes.
Woodpeckers, on the other hand, create their own nesting holes in (generally dead) trees. They have anatomy designed to prevent head injury during hammering into wood, including a straight bill, specialized microstructure of the skull (cranial) bones to increase their strength, a modified hinge between the skull and bill that redirects the force away from the brain, and modifications to the structure of the eye. Most notably, this involves a particularly thick nictitating membrane – sometimes referred to as the third eyelid – which helps to keep the bird’s eye in its socket during the period of rapid deceleration that occurs as the bill strikes the wood. Other adaptations that facilitate their lifestyle include tail feathers that have evolved to provide support and a zygodactylous foot structure (two toes facing forward and two backward) which aids clambering. The two middle tail feathers are especially strong and stiff, much stiffer than a dove’s or starling’s tail feathers. This rigidity is essential, providing a prop of sorts that helps to brace the bird as it works its way up a tree. The extra backwards-pointing toe – perching birds have three toes forward and one backward – which the woodpecker can turn sideways on thinner trunks – affords it better purchase on the tree bark whilst climbing.
Despite their ubiquitous presence across the globe we tend to focus far less attention on our avian inhabitants, turning the majority of our attention upon our mammalian cousins. Yet birds possess so many extraordinary features, and are so perfectly adapted to their environment that the famous aviator – Charles Lindberg – said: “I realised that if I had to choose, I would rather have birds than aeroplanes”…
By Lorraine Doyle – Wildlife Manager, Thanda Safari