Creature Comforts

By Peter Ryan

To care for their plumage, birds undertake a range of activities. Feathers are dead structures that need constant attention to function effectively for flight and insulation. Birds replace their feathers regularly, but this is a costly process, so they spend considerable effort to ensure their feathers remain in good shape for as long as possible.

PREENING

The most obvious of these comfort behaviours is preening, where a bird uses its bill to groom its feathers and skin. Typically, the bill nibbles along the length of each feather from base to tip. This has several functions. First, it cleans feathers of dust and external parasites. Second, coupled with stretching and shaking, preening ensures feathers are aligned correctly.  And thirdly, it repairs any breaks in a feathers vane by reconnecting its inter-locking hooks, like sealing a zip-lock bag. In most birds, preening also serves to spread the oil from the uropygial or “preen” glands over the feathers, skin, legs and bill. A preening bird repeatedly rubs its bill and head over these glands, located at the base of the tail. This coats the bill and head with a thin film of oil, which is then transferred to the rest of the body. Preen oil helps to maintain feather integrity and flexibility, as well as enhancing waterproofing. As a result, preen glands are well developed in most waterbirds. But not cormorants and darters, which have partially or fully wettable feathers to reduce their buoyancy when diving. Preen oil might also help to deter lice, mites and other feather parasites. Birds that have a large diversity of parasites tend to have large preen glands. In a few groups, such as hoopoes and wood-hoopoes, symbiotic bacteria live in the preen gland, making the preen oil particularly pungent. Their presence gives the oil anti-bacterial properties. Which help slow feather degradation. They also make the birds distasteful to mammals such as genets, which probably helps to reduce the risk of predation while roosting in tree cavities.

DUSTING

All birds have preen glands as chicks, but they cease functioning as birds develop in groups such as the ratites (walking birds – Ed.) and bustards. These birds typically use dust to help keep their feathers clean, although this behaviour is by no-means-confined to birds without preen glands. Dusting is common in ground-dwelling birds, especially in arid areas where water is scarce, limiting the options to bathe. Among Southern African birds, it is particularly common in gamebirds, larks and sparrows. A more sophisticated approach is to grow your own “dust”. Herons and some parrots have special powder down feathers that are unique in continuing to grow year round.

ANTING

This is either done indirectly, by lying with wings and tail spread where ants are active and quivering to encourage them to “attack” the bird, or directly, by rubbing ants over the flight feathers. In most instances of direct anting, the ants are discarded after being wiped over the plumage, but some birds do eat them.

SCRATCHING

Birds cant reach all parts of their bodies with their bills, so inaccessible parts such as the head, throat and bill are groomed with the feet in ritualised scratching behaviour. In the extreme case of the sword-billed hummingbird, its bill is longer than its body, rendering it virtually useless for preening, so all grooming is done by the feet.

BATHING

Preening may occur at any time, but it is often associated with bathing. The actual process of bathing varies among birds, from wetting their bills while preening, through standing in water, to swimming and even plunging into water from the air. Some birds also bathe in the rain, or use dew on leaves and other vegetation. Bathing usually is accompanied by vigorous shaking and ruffling of the feathers, and typically is followed by a period of extended preening.

SUNNING

To care for their plumage, birds expose themselves to the heat of the sun on hot days, fluffing up their body feathers and spreading their wings. In vultures, this has been shown to help restore flight feathers to their original shape if they become stressed in flight.

SOCIALIZING

From a human perspective, perhaps the most interesting aspect of comfort behaviours is their use in social context. Birds often preen each other, recalling human couples canoodling. This allopreening does indeed serve to help establish and maintain pair bonds, or social cohesion among group-living birds. It is concentrated on the head area, where birds cant preen themselves with their bills.

Wild Magazine Autumn 2013 
  

What Lies Beneath

By Dr Ian Whyte

I was only ever chased up a tree by an animal once in my 37 years in the Kruger National Park, by a hippo that had come to graze on the lawn in my garden. Though there is little data to corroborate the reputation hippos have as being the mammal that kills more humans than any other in Africa, and i do wonder heather this reputation is deserved, I wasn’t taking any chances. It may well have been the case when humans and hippos tended to live along-side one another and potential for conflict was far greater. Hippos attacking fish boats, raiding crops or simply grazing around villages are all situations with the potential for fatal consequences to humans. These days I suspect elephants have taken over this role.  Humans and elephant populations are growing rapidly in many parts of the continent and conflict is on the rise. Be as it may, hippos remain dangerous animals capable of inflicting fearsome injuries and have been responsible for many human deaths. In most instances attacks on boats or people on the edge of the water are by mothers with small calves.  You only have to look at their teeth to understand why hippos are so fearsome.  Their huge canine teeth, measuring up to 300 millimetres in the lower jaw and 150 millimetres in the upper, grow continuously. These teeth protrude from the skull in such a way that they wear off against each other, keeping them razor sharp. The jaws open wide enough to encompass a human torso. In a bite from a hippo the upper and lower canines would probably meet inside the body, punching two huge holes right through it, almost certainly a fatal injury. Most field guides will tell you that hippos can stay submerged for up to six minutes, but rangers in the Kruger have recorded times of up to eight minutes. Once alarmed, the animals are wary of exposing themselves and will breath by cautiously allowing only the tip of the nostrils to break the surface of the water. So as not to give their position away, they do this in almost complete silence, compared to the explosive release of air normally heard from relaxed animals in the water. Hippo bulls are very territorial. They maintain a territory, usually consisting of a good pool with sandbanks for sunbathing, for many years. The territory is confined to a stretch of river and its immediate embankments, and does not extend to the grazing areas away from the river. Each territory has its associated females and calves that return to the same pool during the daylight hours. This status quo remains while the bull holds tenure, which he does for as long as he can fend off rivals. Displacement by a younger, more vigorous bull results in a upheaval in which the new contender may kill the calves sired by the previous bull. This behaviour ensures the new bulls genes are passes on into future generations and not those of his predecessor. Fighting is generally ritualised with much posturing and open-jawed displaying of the canines.  But sometimes more serious fights erupt in which males may inflict serious wounds by slashing at each other with their sharp canine teeth. These may last for several hours and are accompanied by weird vocalisations such as squeals, grunts and roars. Such battles can result in the death of one, or sometimes both, of the protagonists. Given their size, hippos have an extraordinarily short gestation period of eight months. Growth of the foetus in the womb is incredibly fast. Black rhinos, which are similar in size to hippos, have a gestation time almost twice as long, yet rhino calf weighs less at birth, about 40 kilograms, compared to a newborn hippo at about 50 kilograms. Calves may be born at any time of the year but the majority are born during the mid-summer, rainy months. When the time comes to give birth, female hippos move away from the herd and remain separated for about a fortnight. The calves are capable of going into deep water and can suckle underwater within minutes of being born. Initially the calf stays in shallow water near a shore while the mother grazes nearby. Growth of the first 10 years of life is also rapid. The average increase in weight is in the order of 100 kilograms a year, so that at 10 years old, a hippo can weigh in excess of 1200 kilograms. Males and females are similar in size, the male being only slightly larger than the female.

Wild magazine summer 2013/2013

Wild Lions Near Extinction

News24

Follow the link for the full story on lions near extinction http://www.news24.com/Green/News/Wild-lions-near-extinction-20130415

Photos While On Safari



Herd of baffalo in the water



Cheetah walking in the bush



Zebra's on the road



Foreign Tourists Involved In An Accident In The #KNP

Foreign tourists involved in an accident in the #KNP.. Follow the link for the full story http://www.sanparks.org/about/news/default.php?id=55496

All About Lions

*Lions are the dominant members of the food chain, but it remains a mystery why they kill all other members of the carnivore family as well as several less-competitive species such as baboons, monitie lizards and crocodiles. The logical answer is that this removes potential competitors, but its hard to imagine how a mongoose could compete with a lion or provide a fit meal. Leopards differ from lions in this regard, eating whatever they kill.

*The boisterous rough and tumble of lion cubs not only teaches hunting behaviour, but also develops social skills. lions are uniquely social among all cats, living in prides without dominance hierarchies.

*Cubs and lionesses feed primarily on Zebra, wildebeest and buffalo.

*Male lions eat more buffalo than females do. Their size accounts for their increased hunting success.

*Thanks to their strategy of hunting in a group, lions can kill prey much larger than themselves. Species such as wildebeest are vulnerable to attack by lionsand thus highly preferred. Lionesses co-ordinate group hunts of prey that can run fast and are medium to large in size. Once the prey is detected, it is encircled. Each lioness waits to either rush at or chase down the quarry. Cubs and subadults ait eagerly. When they hear the knock-down they rush to assist and join the feast.

*As they spend most of their time patrolling their territories, typically as a coalition of to, males have had to learn other hunting skills. Male lions in Kruger are successful hunters in their own right, largely killing buffalo, impala and warthog, but not with the same co-ordinated skill as the lionesses.

*Males are not above scavenging from the pride kills of wildebeest, zebra, kudu and waterbuck. When these kills are large adults (above 150kg) males feed with the pride, sometimes pushing the lionesses off the kill but tolerating the cubs.

*When the kill is smaller, one male will pick it up and steal it for himself.

*Lions tend to hunt adult giraffe in terrain where they might slip and fall when chased. This includes mud near the water's edge, rocky areas or the steep banks of rivers.