Pangolin ‘Safety Tags’ | Stingless Bee Bounty | Super Hawk Vision | Pitta Country
Leopards grab rescued pangolins by the tags
Scientists keeping an eye on pangolins rescued from traffickers in Zimbabwe and released into national parks are having to modify the satellite tags they attach to the animals to save them from another threat -- leopards and other predators.
Over a six-year-period, dozens of devices fitted and in some cases refitted to 36 released pangolins were ripped off by predators on up to 33 different occasions, though the removal of the devices was non-fatal.
"Given the size of tooth marks found on devices, removal by large predators, such as spotted hyenas, lions and leopards is likely, although it is difficult to confirm the exact species," the authors state.
Given fears some tags could provide an easy hook to a pangolin meal for these carnivores, the study by researchers from the University of Gothenburg and their Zimbabwean colleagues showed the importance of having well-designed tracking devices that incorporate ‘breaking points’ in the event a predator gets hold of them.
It means the pangolin isn't at risk of ending up on the menu.
Typically tags and transmitters are attached near the margin of an individual pangolin scale, so that the scale isn’t damaged or ripped off in the event of an attack, leaving the pangolin with a potentially fatal chink in its armour.
The team behind the study says it’s also important to avoid using tracking devices that are brightly coloured, or which emit lights or sounds that could attract attention from natural predators, or from poachers.
A pangolin at a game reserve in South Africa | David Brossard | Wikimedia Commons
Honey of stingless bees could help keep Kenyan forest standing
Luhya honey hunters in Kenya’s Kakamega Forest, near Lake Victoria, recognize at least seven different species of stingless bee known to modern science.
The Luhya distinguish between the various species based on their physical traits, nest-building habits, and honey, say the authors of a new ethnobotanical study. This knowledge is ancestral, and shared orally across the generations, the study finds.
Stingless bees are found throughout the tropics, and produce honey that is renowned for its health properties.
The Luhya have at least 26 different non-food uses for stingless bee honey. For example, the honey of Meliponula togoensis, a species known to the Luhya as iwera, is used to treat dysentery; that of Meliponula lendliana (indakala) is used in circumcision ceremonies.
Traditionally, when Luhya honey hunters found nests of stingless bees, they harvested the honey and let the colonies perish. Now, however, the colonies are sold to local stingless beekeepers to raise in small wooden hives. It’s an example of how stingless bee honey production in Kakamega is diversifying.
Kakamega Forest is estimated to have shrunk by 50% between 1978-2016. Harvesting stingless bee honey, which fetches up to 30 US dollars per kilogramme in Kenya, could provide an economic incentive to help keep the forest standing.
Kakamega Forest, in western Kenya | Nao Iizuka | Wikimedia Commons
Africa's ‘super hawk’ has two secrets: no eye ridges and double-jointed legs
Most hawks hunt from above, stooping down upon and striking their unsuspecting prey using the element of surprise.
To do this, they need binocular vision, and ridges above their eyes to prevent them from being blinded by the sun. But one very unique hawk bucks this trend. It is the African harrier-hawk, or gymnogene.
The gymnogene hunts for eggs and nestlings by hanging upside down and pushing its feet into nests that hang from branches or are tucked inside tree cavities. It does this with the help of long, double-jointed legs.
A new study reveals it has another superpower – binocular vision that extends way into the upper portion of the visual field. To facilitate this, the gymnogene lacks eye ridges. It also has a narrow head, allowing it to peer into cavities and nests.
British and French scientists used the ophthalmoscopic reflex technique to compare the eye reflexes of the gymnogene with 20 other birds of prey, including vultures, eagles, hawks and kites.
While the width of the gymnogene’s binocular vision was found to be similar to those birds, it differed by being able to perceive objects located 120 degrees above the bill tip.
Compare that to the bald eagle, which can only perceive things for 60 degrees above the bill; or the Cooper's hawk, whose perception extends to 80 degrees.
The authors say their study provides a clear example of "fine-tuning between sensory ecology and foraging strategies” by this unique African bird of prey.
The gymnogene has a visual field that outperforms other raptors | Ryan Truscott
Nature Notes: Dry forests full of life
Across the Angwa River, and into the dry sandy forests of the Dande Safari Area. These deciduous woodlands and thickets of northern Zimbabwe are known locally as "jesse".
They are the hiding places of buffalo and elephants. After a long, harsh dry season, most of the trees and shrubs are stripped bare of leaves.
Still, there are some splashes of colour: the russet winged fruit of climbing combretums; the fresh scented leaves of wild citrus; the green shoots of the valley paddle-pod.
The latter is a thick creeper that creates the favoured nesting sites of African pittas.
These breathtakingly beautiful birds, with electric-blue wing spots, arrive with the summer rains. They draw birders to remote forests, where the baobabs and manketti trees grow tall and wide.
That trees should prosper on such infertile, acidic soils is a testament to their resilience.
At the fluted base of a torchwood tree I fail to find a single one of its oil-rich seeds. That is a good sign. When torchwood seeds accumulate, it means there are no elephants around to eat them.
Sure enough, close to the road, there is recent elephant dung. It contains the empty husks of the coveted fruit.