Saturday, 25 January 2014

Coordinated Avifaunal Roadcount: the accounting of route WU08 of Summer 2014

Today's CAR route was most memorable from the least number Blue Cranes counted, but its been the trip with the most number of chicks seen, albeit only 3.

As Chris and I headed off to our monitoring route start point today, there was plenty of action which meant we nearly didn't arrive on the start point at the suggested time of one hour after sunrise. There was plenty of small game including duikers and hares on the route from Blue Hill to the Winterhoek turnoff, plus a dispersed flock of Amur Falcons and Lesser Kestrels.

We were so distracted looking up at the whirling raptors, that we were caught by surprise when a Blue Crane took off from the road in front of us. On the verge of the road, the partner slunk along rapidly, before climbing through a gate to get to the veld beyond. It was then that we noticed the chick next to us that the adults had obviously been trying to protect or distract us from.

Blue Crane climbing through a gate

But it was not long before that gangly pile of legs was freaked out by our proximity and to our surprise the Blue Crane colt wriggled its way through the jackal proof fence and into the field where mommy was. This sighting was at the same location where I recorded the display dance about a month earlier.

Blue Crane colt hiding

freaked out

through the wire unscathed and off to find mommy

Our route starts at the interface of renosterveld and Karoo, works its way through some thicket covered hills, and then into wide planes of karoo veld. Now that the ADU has us counting crows and selected raptors, one tends to be very busy.

Pale Chanting Goshawk

Not all Steppe Buzzards perch on poles

Not least because in the Western Cape one also counts a variety of antelope, of which Steenbok is Abundant. Although Kudu are not included on this list, we note them down anyway for ourselves, as this district is big game hunting country, and we feel its a species worth recording.

Four young male kudu know what's good for them and run for the hills

This female kudu looked very unhealthy

The most common animal along the route is the Angora goat, as this is Mohair producing country.

Unfortunately, many stock camps have an electrified wire very low down (ostensibly to keep out jackal). This wire is responsible for the deaths of many tortoises, which simply withdraw their legs when shocked and then suffer one of the most painful deaths imaginable drawn out over an extended period of time. We counted four dead tortoises along one particular stretch of fence.

Electrified to death Leopard Tortoise

For the first time actually on the route we recorded a pair of Secretary Birds. But our Blue Crane Count on route was only 2 – the lowest ever; and the case was the same for Karoo Korhaan – although detecting them is always at the mercy of how much they feel like calling on any particular day. At the end of the route we did spot another pair of cranes with a pair of chicks, a nice way to round off the count.

Previous Car Accountings:

This Leopard Tortoise was not amused by a Fast driver in the Slow lane

Thursday, 23 January 2014

When thunder gods fight: Lightning storm over Blue Hill

The Western and Northern Cape were in the throws of a heat wave yesterday, with the capital of the Klein Karoo – Oudtshoorn – registering 43C. Our kitchen, at 29C seemed cool compared to the 39 outside.

The consequence of the hot day was a convection thunder storm building up over the Swartberg. By late afternoon, black clouds ruled the sky to the north of us. The storms to the north normally pass us by on their tract eastwards over the country. This one was so big, we caught the edge of it.

As the sun disappeared westwards, I ventured outside to capture some shots of the regular lightning bolts coupled with the clouds glowing red from the reflected fires of a setting sun.

As the last daylight was washed from the sky, the storm edged ever closer, the lightning ever closer, distant rumblings of thunder ever closer – but the constant booming made it impossible to count seconds between strikes and thunder – the classic way to estimate storm distance. The first drops of rain fell, and we retreated inside.

By 8pm there were lightning strikes going on at a rate of at least one per second. It was light as much as it was dark. There was no single clash of thunder... the thunder was just a background concert, demons at the instruments of a discordent The Ride of the Valkyries – that classic Richard Wagner symphony. The occasional strike overhead would ring out like a rifle shot.

But it was the shapes and forms of the lightning that had Anja and I glued to the window. Streaks of jagged light were shooting from one side of the hillside to the other as though Thor and Zeus had decided now was the time for the final showdown, the battle to decide who was to reign as Lord of the Thunder Gods. Over the course of the next hour the battle raged further eastwards, with no sign that a victory would be assured for one or the other.

And all of that brought just 4mm of rain.

Saturday, 18 January 2014

Why is a Cape Sugarbird like a Cape Mountain Leopard?

So what do Cape Sugarbirds and Cape Leopards have in common? Both are able to survive in the sometimes very inhospitable Cape Fold Mountains, which often experience freezing temperatures and very high winds. They inhabit the Fynbos biome, which despite being nutrient poor, supports a vast array of unique plant species. This biome is under threat from land use change, alien plant invasion and climatic changes which are resulting in warmer temperatures and increased fire danger indices.
The Fynbos is important not just for South Africa’s biodiversity, but for that of the world – covering just 2% of the planet it is one of five Mediterranean climate ecosystems which account for 20% of all plant biodiversity. Apart from being home to 7000 plants species found nowhere else in the world, it is also home to six endemic species of bird (a third of South Africa’s endemic bird species). Cape Sugarbirds and Orange-breasted Sunbirds are some of the most emblematic of these. Cape Sugarbirds are important pollinators of many kind of protea, and rely on these plants for food and nesting sites. Cape Sugarbirds are abundant in areas with a diverse array of proteas, but are all but absent from areas converted to agriculture or which are too frequently burnt – they are vulnerable to increasing fire frequencies.

In addition, both Cape Sugarbirds and Cape Leopards are being monitored using camera traps. While Cape Sugarbirds do not have the unique spots that the leopards have, they can be given unique identifying features in the form of coloured ring combinations placed on their legs. This is being undertaken by the Fynbos Endemic Birds survey at study sites around Cape Town and towards Baviaanskloof. The Cape Leopard Trust were very kind to loan us some remote sensing cameras to aid us in our quest to find out more about these important birds of the Fynbos. Using the cameras we are busy monitoring visitation rates to proteas, and hoping to detect clues as to bird movements by obtaining resightings in different locations. We are trying to determine how far the birds are moving on a regular basis. Like Cape Leopards, Cape Sugarbirds defend breeding territories – but they have to leave these if the territory does not host a range of food plants that flower all year round.
These Cape Sugarbirds were captured using camera traps. Note the rings on the bird on the right.

Understanding movements is one of the key reasons why we ring birds. It is important to know how far and when birds move, as we can then make habitat management plans in order to ensure the survival of a species – as indeed we must as they are very much part of our South African biodiversity heritage. By understanding the bird movements we will better be able to understand if they will be capable of overcoming the threats to the biodiversity of the region. For example, can they cross a large area of modified landscapes, or areas that have experienced frequent fires that may be threatening local protea populations? What happens if it gets drier and hotter for longer periods?

These are some of the questions that the Fynbos Endemic Bird Survey is attempting to answer. The project is supported by South Africa’s leading bird conservation organisation – Birdlife South Africa, the South African National Biodiversity Institute (SANBI) and the Percy FitzPatrick Institute of African Ornithology (University of Cape Town).

And finally, Cape Sugarbirds and Cape Leopard haunt the urban fringe, perhaps attempting to visit ancestral homelands now so irrevocably replaced by expanses of human domicilia. And of course, encounters with both Cape Sugarbirds and Cape Leopards are welcomed by anyone interested in the natural history and biodiversity of our beautiful country.

This article was originally published in Environment - People and Conservation in Africa Issue 17, Summer 2013, for the Cape Leopard Trust, entitled Cape Sugarbirds and Leopards - the semantics 

Friday, 17 January 2014

Cuddeback vs Bushnell: camera traps pros and cons

Camera Traps are cameras that trigger due to movement, and are commonly used for monitoring wildlife. They are also called Remote Sensing Cameras, Trophy Cams or Trail Cameras. There are a variety of brands – but choosing a camera can be tricky – going by 'specs' can be misleading and lead to disappointment.

I started using camera traps for a project in the Amazon in 2003. Back then it was still film that had to be developed,and a poorly placed camera triggered by a hot waving branch could be very expensive as well as frustrating. Camera traps have come a long way since then in our digital and video dominated world. At least a waving branch is only frustrating now – unwanted images are easily deleted.

During 2006 I saw Cuddeback Capture camera in use for the first time – great quality images in the dingy forest environment. At Blue Hill Nature Reserve we invested in Cuddeback Capture camera traps in 2010 and were not disappointed. The cameras revealed the presence of a range of creatures from genets to leopards, and much of this wildlife we have not yet even seen as these animals are nocturnal and shy.

Cuddeback Capture night time capabilities were excellent - pixelation of this image of an Aardvark were caused by image processing

Cuddeback Capture were good at capturing action in the right light - here a Grey Rhebok on the run

This post on Jaguars is illustrated with photos from the Cuddeback Capture cameras:

A few years later, after drowning one camera in a flood and loosing another (baboons ripped it off the mount) it was time to get some news ones.

One faulty camera had been replaced by the 'improved' Cuddeback Attack that featured video capabilities. This overexposed images at night, but we thought this might be just a camera fault. We ordered 5 more – but even after updating firmware we remain disappointed with the flash of the new generation of Cuddeback cameras. While flash strength can be adjusted, this doesn't seem to help. Night photos are often whited out from over exposure.

overexposure with Cuddeback Attack of 2 leopards. This was before updating Firmware.
After updating firmware - still some odd effects in night time photos - illustrated by this Grey Duiker
Cuddeback Attack daytime images are good - a Grey Duiker in the same position as the previous photo

The old Cuddeback Capture could be installed on a post and processed quickly and conveniently by opening the front flap to change memory cards, settings and batteries. The new design means the camera has to be removed from its mount as access is from the back, which means more fiddling as the screw that tightens the flap also doubles as the mount hold.

There is more functionality on the Attack – but you need a manual to figure out the options, as they are coded. Although I've tried the Guard Duty option (a photo every 15 seconds), this was not useful for me. Lastly, the Trophy Room software that comes free for organising photos is just terrible. While it supposedly does all sorts of tricks to examine your time stamps in relation to moon phases, these are still in development. It is also very biased to North America -  there is a preset list of options for naming animals that cannot be modified and does not apply to anywhere else in the world.

The only plus side to the Attack series is the phenomenal length that the four D cell batteries will last for – literally 3-4 months of continual use with top of the range Duracell or similar. Many pundits prefer Cuddebacks due to the fast trigger speed (with Bushnell you may only get a tail of a passing animal).

Video quality is okay – but there is no sound.

A Cuddeback Attack video:

 I first saw Bushnell Scoutpro in action in the Amazon in 2010. I didn't rush to buy these as the Cuddeback Capture image quality was better at the time. However, they have now become my camera of choice: they are smaller (although this means 8 AA batteries), more versatile (a variety of capture possibilities including multiple images of a passing animal),  and you can figure it out without having a manual in your hand thanks to the digital screen on the inside. It opens from the front (so you don't have to remove the camera from a mount when changing memory cards or batteries) and image quality is acceptable at higher quality settings. I have been using these to monitor wildlife visiting Protea flowers:

Bushnell IR photo - recording a mouse visiting Protea lorifolia flowers
Resolution for both makes is adjustable - this photo of a Malachite Sunbird was at standard resolution, resulting in file sizes less than 1 Mb

I've since gotten over the need to have color image night images, and am now a fan of IR – the infra red capabilities that render black and white night-time photos AND videos (not possible with flash type cameras). They are stealthy, and can be used for surveillance under even very sensitive conditions.  These posts on Black Harriers demonstrate the Bushnell photo capabilities:

A Bushnell ScoutPro video of a Black Harrier on a nest demonstrating Infra Red (IR) capabilities:

Sunday, 5 January 2014

Yellow Flower Crab Spider

Its amazing how distracted and attentive children can be all at the same time. On a morning walk with Eli the other day I was hyperventilating as she wobbled precariously on the edge of a precipice while pointing out a tiny yellow spider perfectly camouflaged on a yellow flower – one of many on a prolifically flowering Osteospermum moniliferum. After self-administering CPR and moving to a safer location away from the cliff, I was able to take a few photos of the spider with Eli sitting on my lap. Eli has no fear of spiders by the way – so arachnaphobia must be something we are taught in my opinion.

The spider is a yellow Flower Crab Spider (Thomisus sp) of the Thomisidae family. They do not build webs and are harmless – although their venom works fast on insects. Some species in this genus can actually change color over the course of several days to blend with the flower on which they sit. Crab spiders are common and numerous and play an important role in keeping insect numbers in check. Most important though – they are just exquisite arachnid jewels and most photogenic.

Saturday, 4 January 2014

Have elaborately ornamented birds evolved extra means to escape predators?

Huge claws of a giant beast encircle you - with sharp talons that at any moment could tighten and squeeze the life out of you. Do you lay back and say “This is it, serves me right for being distracted by that gorgeous member of the opposite sex,” or do you do everything in your power to fight for your life? Most of us, birds included, would not give up without a fight or figuring out some way of escaping.

Those beautiful plumages that distract so many birdwatchers are of course really intended to attract the attention of potential mates, and keep others of the same sex at bay. And if we notice them, so do predators. Anybody that has handled birds will know that there are a variety of anti-predator behaviours displayed by a captured bird, including biting, losing feathers, and screaming which may attract the attention of competitive predators. Like lizards losing their tails, bird behaviours evolve if they provide a chance to escape. For instance, research has shown that the frequency of tailless individuals gives a rough idea of the frequency of successful escape from predation. So some birds may have evolved the ability to lose feathers easily as a distraction or escape technique.

Studies of a range of species have shown that predation affects the expression of what are known as 'secondary sexual characteristics’, including brightly coloured plumages and long tails. Predation risk can be reduced by defences or restriction of signalling to specific times, places or situations, which is why birds like male bishops lose their bright colours outside the breeding season. It also makes sense that since conspicuous sexual signals are common in males, and males and females are often behaviourally and ecologically different, that males and females differ in anti-predatory behaviours.

A recent European study looked at escape techniques in a variety of birds vulnerable to predation by accipiters (small birds of prey) and domestic cats. Birds were mostly captured with mist-nets and were scored for how much they: wriggled; bit (by offering a finger to the captured bird!); lost feathers; called in distress; or displayed ‘tonic immobility’ - a standard and harmless measure of fear where the bird is placed on its back and the time until the bird rights itself recorded. The longer the time, the higher the 'fear' score – and may be a ‘play dead’ trick.
This sugarbird is alive and well, just putting on a display of tonic immobility

Results of the study showed escape behaviours explained variation in susceptibility to both accipiters and cats and was species-specific. This suggests that individuals from different species have evolved specific kinds of escape behaviours, possibly in response to differences in predation risk. For instance, birds that occur in urban and rural habitats vary in their anti-predatory responses – those in urban environments display responses that are deemed more likely to result in their escape from domestic cats (more screaming), while those in rural environments show those more likely due to selective predatory pressure from sparrowhawks (more biting and wriggling).

Species where males and females differ greatly in appearance fall prey to predators more often than monochromatic species (males and females have similar colors). Sexually dichromatic species scream less and have higher tonic immobility than monochromatic species. It could be argued that screaming is a less efficient escape technique, but other studies have shown that sexually dichromatic species have lower genetic similarity among individuals in a population than monochromatic species – so there is less chance of screams warning members of one’s extended family so to speak.

So what are the anti-predatory techniques of some South African Fynbos birds? Anyone who has ever handled a Cape Sugarbird would agree that they are vigorous screamers (this is expected for a monochromatic species) and they use their sharp talons to great effect. As predicted, sexually dichromatic species call less: the smaller Orange-breasted and Southern Double-collared Sunbirds are incessant wrigglers and somewhat surprisingly given their weak bills – they also try to bite. Yellow Bishops are obvious biters with their strong bills designed for cracking seeds and also perhaps the digits of distracted predators. Cape Grassbirds, Victorin’s Warblers and Cape White-eyes are delicate birds which show a mixed range of responses, but all are ‘shedders’ to some degree. This makes me think of advice I have received for how to escape a bear – throw your clothes at it while running away.
This Victorin's Warbler offers up a shed feather while tonically immobile

Getting back to our theme question, birds have a range of ways to escape potential predators, and each bird species tends to have techniques that work differently, some of which involve discarding beautiful plumage if needs be.

Reference: Møller, A. P., Christiansen, S. S. & Mousseauc, T. A. (2011) Sexual signals, risk of predation and escape behavior. Behavioral Ecology 1–8. 

Thanks to Phoebe Barnard for comments on an earlier draft of this – which was turned down from African Birdlife magazine for being too complicated. I’m hoping my small circle of readers were able to follow – it says a lot for your intelligence if you did!

This Malachite Sunbird reckons tonic immobility is for the other (non-sexy) birds

Wednesday, 1 January 2014

Leopard: Face to Face and On Foot.

It was the 24 October, sky grey, stars fading like sugar crystals in grey coffee, the sun only minutes from awakening over the eastern Kougas. We'd been awake since 4am. Craig (a volunteer from the UK), Robyn (researching thermal tolerance in birds) and I had just finished opening the mist nets for the early morning ringing session around a stand of old Sutherlandia. Robyn was keeping an eye on the net for early birds, while Craig and I headed off further south up Sugarbird Valley on an old path dying under the regrowth of grass. We were headed for a particularly steep section, almost ravine like, a favourite hang-out for a family of Cape Rockjumpers, although Verreaux's Eagle had been seen to hunt dassies here too from time to time.

I glanced up at the crags, at an overhanging crag the tweenie in me had often dreamed of rock-climbing one day. An unfamiliar bump silhouetted about a hundred meters away against the skyline made me stop. Despite the sense of urgency that lay with our task of attempting to catch rockjumpers, I swung off my backpack and rummaged around for my binoculars.

“I'm sure its just an odd-shaped Klipspringer” I thought to myself as I lifted my binos to my face, only to be greeted with the so unexpected view of a patterned feline upon the rocks. I was silent for a moment as my brain buzzed through a reality check before gasping “It's a leopard!” to Craig, who was waiting patiently behind me. We crouched down while I pointed out the location, giving Craig time to find his optics. Then we just sat on the sand, looking up at the cat that was sitting comfortably, looking down at us.

Without cameras, for maybe a minute we sat soaking in the view of what I took to be a sleek female, before I dug out the walkie-talkie to radio Robyn. “If you want to see a leopard, you better come quick!”

Less than a minute's walk away, for some reason the leopard did not like the view of another human approaching, moving its head from side to side the way a nervous cat might, and with Robyn only meters from us the leopard got up, took one last look at us and slunk away over the rocks. Robyn hadn't seen it and was gutted and green -  it was Craig's third day in South Africa and only the Brit's second day at Blue Hill.

A few hours later, after laying out the traps, I was on a slow patrol up the side of the valley looking for the rockjumpers which had been avoiding our traps. Perched in the shade of a rock, I was distracted from my task at hand by the barking of dassies from a nearby rocky ridge. Views of their furry backs indicated their alarms were not directed at me, and I returned to my task of sweeping my binos over boulders on the opposing slope when out of the corner of my eye dassies started cascading down the rocky outcrop. Next thing, not more than 30 meters away, a leopard popped out onto the rocks above me. This close the leopard didn't look that pretty at me anymore. Despite my position, the cat had spotted me almost immediately. She watched me for a few long seconds before turning around and disappearing behind the ridge.

Now I was nervous – had she disappeared to find a track down to me, or had it fled? Cape Mountain Leopards are small in comparison to their cousins from the savannas, but she'd be able to do some damage all the same. After a few minutes of her not appearing, I made my way slowly up to the ridge where she had stood. There was no more sign of her. Instead, from this location I could hear the weak yelping of a dassie. I tracked among the rocks until I found the source of the noise emanating from beneath a bear-sized boulder. At the entrance of a bolt hole there were scratch and pug marks – the leopard had clearly been trying to dig up some breakfast.

Of the leopard there was no more sign, but after three years living in the Fynbos, criss crossing it from west to east, from beach to peaks, walking at least every second day along trails with tantalizing evidence of their existence, I'd finally achieved an oh-so-rare sighting of the top predator of the Fynbos and Cape Fold Mountains.

The following are a selection of some of the choice shots of the leopards at Blue Hill Nature Reserve. The collared leopards are part of a research project that have shown territory sizes for this regions are huge - almost twenty thousand hectares for the female (e.g. an area 10x20km), and twice that and more for some of the males. This means the 2300ha Blue Hill Nature Reserve is only about 10% of the territory size of one of these leopards. Most of their territories lie outside protected areas - overlapping farms used for hunting or for livestock, where farmers use a range of lethal control measures. Since their territories are so large, we often go several weeks without a camera catching a glimpse, and with tracks and trails bare of their distinctive pugmarks, so each photo is a trophy for us and a celebration that they are still alive.

The collared leopards use the area most frequently, but we have also caught glimpses of two uncollared leopards:

Lady Leopard as we call her, collared in 2011, she is about 4 years old now

The story of Lady's capture can be read here:

Dassie - Leopard Food

Lady Leopard with cub - see post on left hand side

A rare shot of Lady out and about during the day

Butch - the resident male leopard. Collared initially in the Baviaanskloof itself a long way from Blue Hill.

Princess - or the New Female. It is rare for two female leopards to overlap a territory. Princess seemed to be the resident female for about a year before the return of Lady - whom we'd presumed had been killed in the interim.

Big Boy. We have only a few photos of this massive male leopard, and suspect that our property is marginal to the core of his territory. 

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