Vultures are an overlooked wonder of the bush. Vultures are often thought of as dirty birds – and they were definitely not blessed with good looks. But good looks and table manners do not make a species successful. Vultures’ looks have evolved as a result of function and have assisted them in becoming as successful as they are.
Their huge wingspan allows them to soar to amazing heights, scouring the earth below for any signs of a potential meal. Vultures will often group together in areas where there are hot air thermals, which they will use to rise to heights exceeding three kilometres above the earth’s surface. The highest recorded flight of any bird, that being the Ruppell’s Vulture, was recorded at 11,000 feet (3,35 kilometers).
Just think about the evolutionary adaptations vultures had to make in order to reach these altitudes where there is next to no oxygen and the temperatures can be as low as -60°C (-76°F). In order to combat the cold they have developed a layer of down feathers that are able to insulate them. The low oxygen levels are countered by having an amazing lung system, which is able to utilise even the smallest amount of oxygen effectively. You might ask, ‘why do vultures fly so high?’ It is to use jet streams in order to cover greater distance.
When it comes to feeding these birds of prey are supreme and will deal with the most rotten flesh without so much as a complaint. Their job as the cleaners of the bush means that they can consume this rotting flesh without doing themselves any harm. Most vultures have antibacterial agents in their stomachs which can deal with the rancid flesh. White-backed and Cape Vultures have unique groove and serrated tongues which allow them to access soft flesh which may not be accessible with their beaks. They can fill their crops within 5 minutes allowing them to quickly exit the feeding frenzy and digest the food they have just taken in.
This may all sound simple but the hardest part about getting a meal is finding it. With the vultures soaring at dizzying heights above the earth’s surface, they can still see a dead body lying waiting for them on the ground. At the first sign of a victim the initial spotter will start to drop from the sky toward its meal ticket. The other vultures see this body language and they immediately start heading in to take a closer look. Within minutes vultures from far and wide make their way towards the carcass. Most of the time they will have to sit and wait for the predators to finish feeding before they get their chance at the dinner table but on the rare occasion they will spot an animal that may have died in a fight or from disease before the predators get there. This is where the pecking order kicks in. In the case of an animal that has died naturally or of disease and not been killed by a predator, there will be no open access into the carcass. The smaller vultures have to sit and hope that someone with the correct “cutting” tools will arrive soon so that they can all start to feed. The bird with the hide cutting beak comes in the form of the Lappet-faced Vulture, which dominates at the carcass. Its 2.9 metre wingspan outdoes most of its rivals, with the Cape Vulture coming in second with a 2.6 metre wingspan. The larger birds get the prime feeding positions with the smaller Hooded vultures stealing bits and pieces and moving off to enjoy them.
Large carcasses offer a great opportunity for mating to take place and in between all the feeding the vultures will take the opportunity to mate with their counterparts who have flown in from far and wide for the bounty. This allows for a great mixing of genetics. Those vultures that already have chicks will fly hundreds of kilometres back to their nests and will feed their young by regurgitating food from their crops. The longest recorded flight of a vulture over 24 hours was approximately 1400 kilometres (the distance from Johannesburg to Cape Town).
This amazing species has been persecuted, slated in movies and given a bad reputation in general, but it plays a key role in the effective maintenance of the environment. The birds here at Sabi Sabi are phenomenal and to showcase the variety we have we will be posting pictures every Twitchers Tuesday on our Facebook page.