“Oh look, another cape cormorant”: some trips to the museum

The last few weeks have been spent preparing samples for further identification by bone. This involved carefully sorting through each cleaned and dried scat sample to pick out the hard bits (i.e. bones, teeth, claws and nails) and package them separately. This makes it easier for comparison to reference skeletal material. Next, I decided to reorganise the samples according to prey group by date: rodents (the large majority!), other mammals, birds and reptiles. With all my samples neatly packed and organised they were ready for a trip to the museum!

I was very excited to have (finally) organised a meeting with Graham Avery, a retired museum curator and archaeozoologist at Iziko Museums of South Africa. He has expertise in identifying southern African bird bones, as well as larger mammals. With his little dog Suzy for company, we quickly got to work looking through my bird samples, using his impressive collection of reference bird skeletons. Each reference specimen has been carefully cleaned, each bone neatly labeled and placed into a brown cardboard box.

The trick is comparing a broken piece of mangled bone from the scat to a bone from the reference collection – which sometimes takes a while to find! Graham is remarkably good at this. If a bone is diagnostic, even if it’s just a fragment, we can narrow it down to a specific bird group and very often to a specific species. The best samples are those with a bit of coracoid, quadrate, furcula, tarsometatarsus or humerus.

Sometimes the sample resembles “rice crispies” (as Graham puts it), but quite often there was something identifiable. Often, we just have to use what we can get… Claws can be quite informative:

Sometimes there’s evidence of the caracal feeding on the bones:

And sometimes we have to look at a few different pieces. This gets tricky when there’s more than one species in the sample.

In the beginning we had a nice variety of birds: Cape francolin, Egyptian goose, guinea fowl, yellow billed duck and a gull here and there. However, as we started getting to the Cape Point area samples, things got a little less varied and a lot more predictable very fast. Things is, the caracals only really eat cormorants down there. Which would have been fine, except that all those samples were grouped together. So we had to look at 88 cape cormorant samples. Consecutively.

Fortunately, things have become a bit more interesting now that we’ve moved onto what I labeled as “unknown” and the larger mammals. We’re still working on those, and I’m really loving finally getting some confirmed identifications! It’s such a relief after staring at these samples for so long. The next step is to meet with Graham’s wife Margaret Avery who is the go-to expert on southern African micro-mammal cranial bones and teeth. I know most of the samples will be vlei rat, but I’m super interested to see which other species of rodents we’re going to find.

Appreciation post

This project has challenged me in many ways so far, not least because I took it on so late in the year. I feel under constant time pressure with so much to catch up on and get done. Thankfully, I have a team of wonderful student volunteers who are passionate about carnivore biology and conservation! They have helped so much with processing my samples in their breaks between lectures and practicals, fitting it all into their busy schedules. So thanks guys!

The people who have helped me out so far are: Alveena Aziz, Caton Schutte, Clara Steyn, Dayna Hegarty, Kaelin Stemmet, Katherine Chaplin, Kyra McKellar, Lindsay Powell, Megan Pockalny, Michelle Pretorius, Shakirah Rylan, Tara van Ryneveld and Vivienne Coetzee. Thanks also go to some of the UCP interns who have become involved.

Gabi Leighton

SAWMA symposium 2016

I was fortunate enough to attend the annual South African Wildlife Management Association symposium in Tzaneen, Limpopo last month.

I presented some of the preliminary findings on the Cape Town caracals’ diet, focusing on the differences between two methods (kills found at GPS clusters and scat). We had to make a poster and also give a 5 minute speed-presentation of our work.

This was a really valuable few days of interesting talks and people. Very glad that I went and was super pleased to win the prize for the best student poster!

Preview of the poster I presented at the symposium

Preview of the poster I presented at the symposium

I think the next symposium will be in the Western Cape, so hopefully I can go again, and this time do a longer talk about my work!

Gabi Leighton

Some (very) preliminary diet findings

Here are a few of the more interesting prey items found in the scat analysis so far. Most of the samples contain mammalian prey items (i.e. composed mainly of hair), and of those, most seem to be rodent. I still need to go through all those with hair and look at cross-sections under the microscope to identify the species (or at least to genus level). Nevertheless, these are the more exciting ones:

Hope you enjoy the photos!

Gabi Leighton

Caracal diet field trips

I was lucky enough to join in on some field work action earlier this year… This involves setting traps to catch the cats (much trickier than it sounds!) and investigating GPS clusters (i.e. points where the cats have been hanging out for a while) to find evidence of kills and scat, which I’m using for my diet analysis.

No such thing as a free caracal lunch

This is just a brief introduction to the caracal diet aspect of the Urban Caracal Project, which will also be documented here.

I’m an MSc Biological Sciences student in my first year of study at the University of Cape Town. My research aim is to investigate the diet of caracal (aka “rooikat”) living and hunting in the urban spaces of Cape Town, South Africa. These elusive yet adaptable medium-sized cats have managed to persist in a city with an increasingly hardening urban edge; using greenbelts, empty land as well as natural areas. The latter is mostly land forming part of the Table Mountain National Park (TMNP).

Most citizens of Cape Town are surprised to hear that caracals live in such close proximity, perhaps illustrating how good they are at going unseen! As can be seen on this website, a lot of really exciting work is being done to study the effects that urbanisation is having on these cats, from movement patterns and gene flow to rodenticide and disease exposure. My project is a small part of this larger ongoing research effort and will investigate their diet. However, I’m hoping to make it a bit more interesting for myself by putting the dietary data in a spatial context, linking what they choose to eat, where they choose to eat it and how this is influenced by urbanisation. We expect that while there might be easy pickings near the urban edge, this may draw caracals closer to the risks of the big city… There ain’t no such thing as a free lunch!

Gabi Leighton