Today’s guest blogger is Lucy Hughes. Lucy lived and worked on a private nature reserve in South Africa for four years, carrying out field research that included a camera-trap study into the reserve’s leopard population and twice monthly bird surveys for Cape Town University’s Birds in Reserves Project (BIRP).
Arrhhh, that really hurts! A three inch thorn had just penetrated my, admittedly inadequate, footwear and was stuck deep in the sole of my foot. Thorns are a serious hazard of camera trap placement in the South African bushveld where plants with thorns or hooks seem to make up about 90% of species.
My colleague Michelle ran back to the landy to get a first aid kit whilst I set about extracting the thorn, there seemed to be an awful lot of blood. I watched the path eagerly for Michelle’s return but as she got near she seemed to slow down and as she opened her mouth to speak I knew exactly what she was going to say. “Luce, if it’s not too painful, what about spreading your blood around a bit?”
Callous as it may seem it wasn’t a bad idea. We had been having trouble with capturing clear night shots of leopards. They always seem to be in a hurry and the shots we had were often blurry making it impossible to id the individuals. We needed a way to get the leopards to pause for a second or two in shot of the camera trap.
We had been advised that scent was the answer and were experimenting with various different ones and now it seemed human blood was to be the next test. I dutifully hobbled out in front of the camera and scraped my bleeding foot around on a nice flat rock Michelle had procured, wondering about the sensibleness of using human blood as bait for a predator. My slight discomfort was all in the name of science.
In the end it didn’t work, It rained a couple of nights later and my efforts where washed away. We never did find the perfect scent. We were told that tinned sardines worked wonders as well as catnip and perfume. We tried them all. It seems our cats where immune to these. The only thing that stopped them in their tracks was the scent of other leopards. I did learn however that the scent of tinned sardines was particularly interesting to giraffe of all animals. My method was to bury a plastic cup up to its rim in sand and put a blob of sardines in the cup. Now you would have thought that giraffe would have walked on by but as the picture below testifies, giraffe just have to take a closer look. You always learn something new!
If you had visited the lion research house between 2008 and 2010, in addition to Fabio, the stuffed lion, the mantelpiece full of animal skulls, and the aquarium of incredibly hardy fish, you would have seen this photo of a male giraffe, which I taped to one of the bedroom doors:
For the last few years, I’ve tracked these quiet giants of the Serengeti woodlands, studying their population dynamics, the vegetation they eat, and their interactions with lions and people.
We can learn a lot by keeping track of individual giraffes. Luckily, it turns out that each giraffe is born with a unique set of coat markings that persist throughout life, like human fingerprints or lion whisker spots. So, each field season, I arrived in Serengeti stocked with the materials necessary to catalogue the many giraffes I would encounter: several hundred 5 x 8 index cards, ink cartridges for the printer, sharp scissors, and a good supply of glue sticks. My days in the field often went as follows. Morning and afternoon: meander through the woodlands locating and photographing giraffes. Evenings: work through the day’s photographs, identifying giraffes and making ID cards for any new individuals. For fun, I assigned a different first name to each individual. The female below is named Flopsy, for her deformed right ear:
Among Serengeti giraffes, which belong to the Masai subspecies, coat markings vary from blocky to highly stellate, or star-like. While the patterns do not change, the color of the markings can grow darker as giraffes age, particularly for males. The shape, color and arrangement of the coat markings are all useful for telling apart different individuals. Other traits are useful as well, such as tail length or ossicone size, shape and hairiness. (Ossicone is the name for the bony, skin-covered horns of a giraffe.) I’ve included some giraffe photos below so you can try your hand at giraffe pattern matching. See if you can match the individual on the top row with any of the individuals in the bottom two rows:
Sexing giraffes is usually easy, especially at close range or from photograph. Aside from the obvious, adult males can be distinguished from females by their larger size, skull ossification (the ossicones of males are larger and mature males acquire additional bony skull protrusions) and their more erect posture. Sexing young calves is a bit trickier. The genitals of male calves are small and calves aren’t always willing to pose for the camera.
Here is an example of a mature male giraffe with significant skull ossification:
By the end of my 2010 field season, I’d amassed a catalogue of almost 1,000 giraffes. (Identifying giraffes by eye can be a laborious and error-prone process but Doug Bolger and colleagues at Dartmouth University have now released Wild-ID, software that assists with giraffe pattern recognition.
We are hoping that we can use the plentiful giraffe images coming in from the camera trap study to maintain this giraffe database and to monitor the population. It turns out, though, that many of the camera trap images contain only giraffe legs, which are much harder to use for identification than flanks.