Coral Cave Bats | Ants Protecting Birds | Threatened Raptors | A Kind of Magic
Protecting coral caves to save endangered bats
Kenya’s coral caves are important roosting sites for endangered Hildegarde’s tomb bats, near-threatened striped leaf-nosed bats, among others.
The caves’ proximity to the coast, however, puts bats in competition with real estate developers.
Kaboga Cave, near the coastal town of Watamu, is situated on what was previously privately-owned land. The owner recently died and developers parcelled out the land to build a shopping centre and apartment complex.
In August, conservationists led by Bat Conservation International (BCI) stepped in to secure the land that remained around the cave. The cave will now be managed and protected by a Kenyan NGO, says BCI.
The entire population of Hildegarde's tomb bats lives in only a dozen known cave roosts dotted along the coasts of Kenya, northern Tanzania and Zanzibar, according to the International Union for Conservation of Nature.
Most of the Kenyan caves are on private or community-owned land where they have little or no protection. Many people associate bats with witchcraft or bad omens, according to Kenyan researchers, despite the animals’ vital role in spreading the seeds of forest trees and eating insect pests that harm crops.
The work to save Kaboga Cave reveals what needs to be done at other known roosting sites, and quickly.
Hundreds of bats live in Kenya’s Shimoni Slave Caves | Maina Kiarie | Wikimedia Commons
Why some Kenyan savanna birds choose to nest in trees occupied by feisty ants
Nesting birds in a Kenyan savanna choose trees occupied by aggressive acacia ants because the tiny insects offer the birds and their young protection from predators.
Jesse Alston, from the University of Arizona, and his colleagues at Kenya’s Mpala Research Centre and Conservancy, recently discovered that superb starlings, grey-headed sparrows and grey-capped social weavers nested almost exclusively in whistling thorns occupied by the two most aggressive species of acacia ants.
Out of 60 nests built by the three species and two unknowns, only one was built in a whistling thorn occupied by a less aggressive ant species.
Acacia ants bite elephants that disturb the whistling trees’ foliage (in return for nectar exuded by the tree and shelter in swellings on the trees’ branches). They also attack snakes or mongooses that shake the branches of the trees when they try to steal eggs or chicks from birds’ nests. But they don’t attack the birds.
One species of acacia ant is also a “tree architect” — pruning the buds of whistling thorns, providing denser leaf cover that probably helps to keep birds’ nests hidden.
Jesse told me that on the surface whistling thorn savannas appear to be unusually species-poor.
“The tree canopy layer is almost a [whistling thorn] monoculture and the grass layer is dominated by very few species as well,” he says. “But hidden in this seeming simplicity is a complex relationship that connects ants, trees, elephants, songbirds, and a whole host of nest predators.”
Hollow tree swellings offer shelter to acacia ants | Christiaan Kooyman | Wikimedia Commons
Africa’s birds of prey at risk of extinction, says a new study
A new study documents the rapid decline of African birds of prey in West, East, southern and Central Africa.
Some of the 42 species studied were found to have declined by more than 90% over the past 20-40 years.
The study, published in the journal Nature, Ecology & Evolution, says two-thirds of these birds now qualify as globally-threatened due to habitat loss and direct or indirect persecution like poisoning and electrocution.
Affected species include iconic and charismatic ones like secretarybirds, martial eagles and bateleurs. Secretarybirds were found to have declined by 85% over three generation lengths — around 30.3 years. Slightly longer-lived bateleurs were found to have declined by 87% over 44.7 years.
The researchers say that birds of prey, especially larger ones, face a “double jeopardy" because in addition to experiencing population declines, they are increasingly dependent on protected areas.
Estimated declines of the surveyed birds were more than twice as high in unprotected areas than in protected ones.
The authors say the reliance of African birds of prey on protected areas substantiates recent international calls to effectively conserve and manage at least 30% of the world’s surface by 2030.
The world also needs to wake up to the importance of African wildlife that doesn’t walk on four legs.
As co-author Darcy Ogada told me: “We want to see African raptors recognised and appreciated for their importance, adding to Africa's image as the home of large, charismatic mammals.”
Secretarybird on the wing in Maasai Mara Game Reserve | Lip Kee | Wikimedia Commons
Nature Notes: A kind of magic
My Dad has been caring for my mother, who’s not been well these last few months. Recently he made some adjustments to the position of the bird bath in the corner of their tiny garden in eastern Zimbabwe. This is so that my Mum can watch it when she’s feeling well enough to sit up.
The bird bath is white, waist-high, sturdy and at least as old as me. Wonderfully, its new position appears to have boosted bird visits.
Along with the usual brimstone canaries, golden weavers and red-throated twinspots, there have been ornately-decorated finches with bright red faces known as green-winged pytilias, and fast-winged olive sunbirds normally only seen a fair distance from my parents’ home.
The biggest surprise of all, however, arrived just before Christmas. My Dad recorded it on his local birders’ chat group: “Visitor to our birdbath at 15:30 -- an eastern bronze-naped pigeon.”
The eastern bronze-naped pigeon is a reclusive forest bird, more often heard than seen.
“When you can’t go looking for them, they come to visit,” Dad wrote.
