Urban caracals sometimes feast on raptors

05 July 2017 | STORY Ian Dickinson, EarthTouch News

In the shadow of Cape Town's famously flat-topped mountain lurks a russet-coloured hunter. If you're lucky, you might glimpse the outline of a stealthy cat darting across one of the congested highways that carve the city's white beaches from the remaining pockets of fynbos fringing the metropolis.
 

As secretive as they are resilient, caracals are rarely seen by the residents of the Mother City, but research data from collared cats paints a picture of adaptation and survival. The ability of these elusive predators to live alongside humans in one of South Africa's most populated places comes down, at least in part, to their varied diets. Cape caracals are unfussy eaters, and even birds of prey occasionally feature on the menu. 

For the last year or so, graduate student Gabriella Leighton , in the Department of Biological Sciences, has been sifting through tiny fragments of mouse bones, or carefully scanning blurry photos of feathers to decipher their origins – all in order to learn more about the diets of the tuft-eared wild cats that roam the Cape Peninsula. Working with the Urban Caracal Project – a scientific supergroup that's partnered with the University of Cape Town, the Cape Leopard Trust, the Universities of California (Santa Cruz and Los Angeles), South African National Parks, the City of Cape Town as well as private landowners – Leighton hopes to find out not just what the cats eat, but also how urbanisation has influenced their meal choices.

So far, she's discovered that these lynx-like felines will scoff down just about anything.

Introduced species like goats, sheep, chickens and peacocks have all wound up on the wrong end of caracal claws, and even domestic cats occasionally fall victim to their wilder feline cousins. Cape Town's pet-owners need not worry too much, though – the predators much prefer other small mammals and, particularly in the Cape Peninsula populations, feathered prey.

For Leighton, this means examining scat, stomach contents and carcass remains at caracal kill sites before sleuthing which species the bits and pieces belong to. GPS data from tracking collars help to identify when a caracal has made a kill. "If a cat stays in an area long enough, a collection of GPS points form in that location, which is known as a GPS cluster," explains Leighton when asked how data are collected for the project. "These clusters were then investigated for signs of a kill, scat or resting beds." 
 

Protea is a healthy female who was humanely captured and collared by the Urban Caracal Project earlier this year. Her main stomping ground is the Cape Point Nature Reserve, a 7,750-hectare strip of prime wildlife habitat that juts into the Atlantic south of Cape Town. While she mostly moves along the coast, possibly preying on sea birds, Protea does occasionally venture north to slink undetected past residential homes – much like the more urban-adapted cats of nearby Table Mountain National Park. 

Protea is one of 26 individuals that have been fitted with tracking collars since the Urban Caracal Project started in 2014. Although some of the cats have since succumbed to the pressures of urban living, Protea and others continue to provide the project with vital intel about just how these animals have adapted to their role as apex predators in an expanding cityscape.

Further north, in the suburb of Noordhoek, another case of raptorcide was opened. And this one was a bit more complex. Grisly photos of the crime scene revealed a raptor's head and a smattering of feathers obscured by leaves and dappled light. Stumped, Leighton called on Jessleena Suri, a bird nerd with a degree on urban black sparrowhawks under her belt. The verdict? It turned out the victim was a juvenile, its reddish-brown feathers identified by Suri as belonging to a young jackal buzzard (Buteo rufofuscus). Locals have probably seen these small raptors perched on roadside telephone poles – a good vantage point for parachuting down on rodents and birds below. Perhaps inexperience was this young buzzard's downfall.

While caracal poop yields a smorgasbord of dietary intel, the remains observed at kill sites in the field are mostly limited to those of birds. "Feathers are easy to find and not consumed by the caracals," says Leighton. Identifying the avian kills doesn't usually present too much of a challenge: spotty black feathers belong to guineafowl, while Egyptian geese sport greenish, brown-and-white quills with fluffy barred down. For less distinctive plumage, however, Leighton outsources expertise from the more ornithologically inclined.

She didn't need help cracking her first case of caracal-caused raptor death, though. Photos of dark feathers edged with teeth-like strips of white were enough to go on: they once belonged to a rock kestrel (Falco rupicolus). These slender raptors are common throughout South Africa, but are known to breed on the rocky slopes of the Cape Point area. The birds hunt on the ground and prefer foraging in open fields, where it's easier to spring a surprise attack on an unsuspecting rat or pigeon. It's possible that this kestrel was preoccupied with just such a hunt when a caracal named Protea (TMC24 if you prefer her more formal title) pounced from the undergrowth and dispatched it for an afternoon snack.

Despite their opportunistic and incredibly adaptive nature, caracals in the Cape are not immune to the threats of city life. Many cats perish in collisions with vehicles as they dart across busy highways. Rat poison is also a major threat. Anticoagulant rodenticides used to control mouse and rat populations often work their way up the food chain, with devastating effects on an array of predatory species. More research is vital for understanding the unique set of circumstances facing these urban cats.

An unfussy diet is not necessarily enough to sustain the caracals' into the future. Their taste for raptors is more likely the result of circumstances, not an innate preference. "Caracals are opportunistic, generalist predators and will take what they can get," explains Leighton. Indeed, her research has documented only three raptor kills so far. But the final example is perhaps the most captivating.

Once again puzzled by the evidence, Leighton called on professional birder Campbell Fleming. With a bit of help from an online feather quiz, Leighton and Fleming were able to identify the prey as a spotted eagle owl (Bubo africanus). This time, a juvenile male caracal named Strandloper ("Beach-walker") was responsible.

A showdown between secretive city-prowler and nocturnal, winged assassin is about as juicy as urban predation gets. But the late-night fight also offers us a glimmer of optimism. Despite some steep odds, perhaps versatile wild cats like caracals can still eke out an existence amid urban development. Perhaps there is hope that while the city sleeps, the tawny ghosts of the Cape Peninsula can continue to prowl the top of the food chain.


This story was originally published by EarthTouch News Network


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