Poisoned Reunion Harriers | Mountains Worth Billions | A Zimbabwean Phoenix
Rat poison threatens endangered Reunion harriers
New research out of Reunion shows that endangered and endemic Reunion harriers are dying or becoming impaired after eating rats and mice poisoned by inhabitants of the Indian Ocean island — and now scientists say the birds of prey risk becoming extinct.
The researchers spent 10 years studying harrier nests on foot or with drones, to monitor clutch sizes, hatching success and the fledgling rates of chicks.
The team found that these "breeding parameters" were low, not only compared with other harrier species around the world, but also with Reunion harriers studied 40 years ago.
The team placed GPS tags on a number of adult birds to confirm they too were hit by low survival rates.
Rat poison is used outdoors by islanders to protect their crops and prevent outbreaks of leptospirosis, a bacterial disease spread by rodents that is a growing public health concern on the island.
Harriers have adapted to eating rodents — introduced to the island centuries ago — to supplement their usual prey of insects, birds and reptiles.
If rat poison doesn't kill the adult harriers outright (earlier studies show that 93% of harrier carcasses contain rat poison), small doses dull their senses, making them less effective at hunting, or vulnerable to collisions with cars or power lines.
The low hatching success and low adult survival rates are a double whammy, and the Reunion harrier population is forecast to decline by 11% per year.
"Our population projections showed a very high risk of quasi-extinction within the next 30–50 years," the authors state.
Egg clutch sizes of the Reunion harrier were also found to be lower than in the 1970s. That could be an adaptation to a “slower pace of life” — a bird equivalent of ‘island time’ — that is also seen in the closely-related Madagascar harrier.
It’s an adaptation that could ultimately prove costly for the species.
A male Reunion harrier | François Dorothé | Wikimedia Commons
Tanzania’s Eastern Arc Mountains valued at more than $8 billion
For the first time, scientists and conservationists have valued the ecosystem services provided by a large mountain range in Tanzania, and they are estimated to be worth billions of US dollars.
The Eastern Arc Mountains (EAMs) consist of a chain of a dozen isolated mountain blocks that extend across the east of the country. They are covered in montane evergreen rainforest, whose trees are believed to be among the most effective in the world at storing carbon.
After 10 years of research the team behind the latest study published in the journal Environmental and Resource Economics, says that the EAMs provide nature-based benefits to the world, including climate regulation, worth a staggering $8.2 billion.
Local Tanzanians, however, receive no incentive to protect the mountain forests.
In places where the forests are officially designated as reserves they receive no compensation for the loss of income they could receive if they felled the trees to make way for crops or for commercial timber, the study notes.
The scientists say the international community must play a bigger role in protecting the forests and ensuring they continue to deliver their vital ecosystem services.
They estimate conservation investments worth $2 billion would need to be made in the EAMs over the next 20 years. Without this, they predict there will be “continued diminution of the region’s biodiversity and carbon stores.”
International funding could, for instance, help small-scale farmers living close to the mountains to increase production on their existing farms, and reduce the need for them to clear more trees.
The EAMs are rich in plants and animals found nowhere else on earth, including dozens of chameleons, frogs and toads that are unique to each mountain block.
Overall, the mountains are estimated to have lost more than 70% of their original forest cover.
Nguru – one of the 12 massifs within the Eastern Arc Mountain chain | Ryan Truscott
Nature Notes: a Zimbabwean phoenix
At this time of the year — the height of Zimbabwe’s dry season — it’s not uncommon to find areas of freshly-burnt grass.
In Harare’s Haka Nature Reserve, east of the city, carefully controlled burns are done once a year by staff in sections of the park to maintain the ecological balance of its grasslands.
On a visit a few days ago, our family drove past one of these burnt patches. I told my son, who was behind the wheel, to stop the car. I looked through binoculars. It didn’t take me long to find what I was looking for.
Two diminutive figures — alternately walking, stopping and bobbing — made their way through the ashes. It was a pair of Temminck’s coursers. These long-legged, plover-sized birds are nomads that arrive at burnt patches of grasslands within days of a fire.
The blackened ground makes it easier for them to hunt for their insect prey. Much to the joy of birdwatchers like me, it also enhances their striking plumage, which consists of a rich reddish-brown crown, dark-tipped wings and a snow-white belly.
To me these birds always resemble beautiful phoenixes rising out of the ashes.
The Temminck’s courser is a close relative of another seasonal visitor to Haka Park: the bronze-winged courser.
We occasionally disturb these in their day-time roosts on the edge of Haka’s deciduous woodlands.
When they take flight, they flash white, black and beige underwings. Having similar food requirements, the two courser species appear to partition resources by foraging at different times: the Temminck’s by day; the bronze-winged by night.
The late Zimbabwean ornithologist, Michael Irwin, noted that the nocturnal habits of the bronze-winged coursers come at a terrible price: many frequent dirt roads at night, and are sometimes killed by unwary motorists.