Robin Hoskyns Nature Photography – Blog

Images and stories of nature, science and conservation.


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Anja Reserve: finding an icon of Madagascar

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Last weekend we visited Anja Community Reserve. This is a tiny reserve of only 30 hectares but it is the closest place to Ranomafana to see the icon of Madagascar, the Ring-Tailed Lemur. Despite its tiny size Anja is home to over 300 Ring-Tails which are well habituated to tourists. As a private community reserve all entrance fees are put towards local development projects.

After arriving and paying our entrance fees we quickly found some ring-tails in the small fragment of dry forest located in a gap between the cliffs. The light wasn’t too good and there were quite a few other tourists so after watching the lemurs for a while we left them to it and headed up to the cliffs to see the view.

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After a short walk and some rock hopping we got up to the view point looking out across the valley over houses and rice paddies. The landscape is totally different to the eastern rainforest slopes and is much more representative of the central Madagascan plateau. Although this was probably once all forest it is much drier than Ranomafana or Kianjavato. We spent a little while soaking up the epic scenery and just as the light was starting to get nice someone spotted a group of Ring-Tails making their way up the rocks towards the caves where they spend the night.

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I managed to clamber down and get some shots of them sitting on the rocks, soaking up the last of the suns warmth with the epic back drop across the valley. I was having a great time and could have stayed following the Lemurs until they finally went to sleep however the guide was getting impatient for us to get back as we were only half way round the two hour circuit. Very reluctantly I left the Ring-Tails to go about their business and followed the guide back down through the forest.

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Walking back out of the reserve I thought I had missed the best of the light on the cliffs however as we got to the car park the sun just broke through casting a strip of golden light across the cliff face. On the taxi-brousse back to Fianarantsoa I was buzzing from a somewhat rushed but extremely productive two and a half hours of photography.

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Poison Frogs and Convergent Evolution

Mantella baroni, common names include: Baron's Mantella, Painted Mantella, Harlequin Mantella, Variegated Mantella

Mantella baroni, common names include: Baron’s Mantella, Painted Mantella, Harlequin Mantella, Variegated Mantella

Although it is late in the season for finding Mantella frogs in Ranomafana, after a couple of hours of searching we found one. I say we but the hard work was all down to my guide Lova who knew exactly where to look. Mantella, even though brightly coloured, are hard to find as they tend to sit in refuges by streams and under leaf litter. The most reliable way to find them is by their call, a  short click noise, however they only tend to do this in the wet season when temperatures are higher so we just had to rely on Lova’s knowledge, a bit of luck and a couple of hours spent poking around in holes with a stick.

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At only 2.5cm these are small frogs!

The most interesting thing about these small brightly coloured frogs is that they share such striking similarities with neotropical Dendrobatids or Poison Dart Frogs.  Although genetically unrelated, Mantella and some Dendrobatid frogs share many of the same features: toxic skin chemicals, terrestrial eggs, small body size, toothless jaws, a specialist diet composed largely of ants, active diurnal foraging, and aposematic (warning) coloration. All of which are considered to have evolved completely separately, a process called convergent evolution.

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They also do not sit still making them very difficult to photograph!

Convergent evolution is defined as the process by which similar features evolve separately in species with separate lineages. In other words evolution creates animals with attributes that have a similar form or function that were not present in the last common ancestor of each species. These traits usually enable animals to fill very similar ecological niches.

In both Mantella and Dendrobatids, defensive chemicals appear to be closely associated with the evolution of aposematism (warning colouration) as a visual warning of their toxicity to potential predators, and active diurnal foraging, a behaviour that is generally rare in frogs.

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M. baroni is very similar to M. madagascarensis however it lacks the red flash marks on the legs and horseshoe shape under the chin.

Although wild poison frogs retain toxic skin alkaloids for several years in captivity, they do not seem to be able to produce their own toxic alkaloids in fact they accumulate these toxins from their diet. Toxic alkaloids have been shown to be absent in Dendrobatid and Mantella frogs when raised in captivity on a diet of fruit flies however these individuals will readily accumulate alkaloids when added to their diet.

The foraging behaviour and diet of Mantella is not yet well documented relative to Dendrobatids however ants are known to dominate the diet of Mantella. A study conducted in Ranomafana National Park collected Mantellid frogs and arthropods with the potential to be sources of alkaloid chemicals. The study found that 13 of the 16 alkaloid compounds found in the arthropods of Ranomafana are also known in other ants, beetles, and frogs endemic to the neotropics and that 9 of the 12 alkaloids found in Mantella are also found in Dendrobatids.

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Because ants are a common or even dominant part of poison frog diets the presence of suitable toxic alkaloids in ants may have been the essential requirement for the evolution of chemical defence in both Malagasy and Neotropical poison frogs. The finding that endemic Malagasy ants contain these toxic alkaloids is evidence to support convergent evolution. Furthermore the convergence seen between the two groups of frogs might itself have been driven by convergent evolution in the unrelated ant groups found in Madagascar and the Neotropics.

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Reference:

Clark, V. C., Raxworthy, C. J., Rakotomalala, V., Sierwald, P., & Fisher, B. L. (2005). Convergent evolution of chemical defense in poison frogs and arthropod prey between Madagascar and the Neotropics. Proceedings of the National Academy of Sciences of the United States of America, 102(33), 11617-11622.


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Frog Diversity in Ranomafana

Boophis madagascariensis

Boophis madagascariensis

In the past couple of weeks I have been going out photographing one of my favorite subjects, frogs! Ranomafana has one of the highest amphibian diversities of any national park in the country with only Andasibe offering any competition. Of the 300+ described species of frog in Madagascar all except two are endemic and at least 120 of those have been found in Ranomafana including 8 potential species endemic to the park.

Spinomantis aglavei

Spinomantis aglavei

Spinomantis aglavei

Spinomantis aglavei

According to the Global Amphibian Assessment (GAA) in 2004, Madagascar ranks as the country with the 12th highest amphibian species richness however it probably should be higher than this as over 200 candidate species have been identified since. This would make the estimated total number of frog species over 500 and would mean Madagascar is home to roughly 4.3% of the world’s amphibians whilst occupying less than 0.5% of the worlds land area.

Gephyromantis tschenki

Gephyromantis tschenki

Boophis reticulatus

Boophis reticulatus

The largest family of frogs in Madagascar is the Mantellidae which is very diverse and is estimated to have colonised Madagascar around 58 million years ago. Some species of the Mantella genus share convergent features with neotropical dendrobatids (poison dart frogs) with their sharply contrasting aposematic (warning) colouration being associated with toxic skin.

Mantella baroni, common names include: Baron's Mantella, Painted Mantella, Harlequin Mantella, Variegated Mantella

Mantella baroni, often called Painted Mantella or Harlequin Mantella

Boophis is another endemic genus of frogs belonging to the family Mantellidae. This genus is known for its brightly coloured eyes which it has been hypothesised act as an anti-predator startle response. The brightly coloured sections usually remain hidden during the day when the frog is resting but suddenly become visible when the frog opens its eyes.

Boophis tasymena

Boophis tasymena – Polka-Dot Bright-Eyed Frog

Boophis tasymena

Boophis tasymena – Polka-Dot Bright-Eyed Frog

Almost all Malagasy rainforest frogs are either terrestrial and diurnal or arboreal and nocturnal. This is probably because of alternating predation pressure from birds in trees during the day and snakes, tenrecs and other predators on the ground at night.

Mantidactylus femoralis

Mantidactylus femoralis?

Plethodontohyla notosticta

Plethodontohyla notosticta

As with amphibians elsewhere in the world Malagasy frogs face numerous threats. Ongoing habitat destruction has already led to destruction of 90% of the original vegetation and threatens most species to some extent.

There are recent reports of the arrival of Asian common toads (Duttaphrynus melanostictus) in Madagascar, most likely arriving inside shipping containers from Asia. This species’ relative, the cane toad (Rhinella marina), has caused widespread ecological destruction in Australia, and there is now concern that an invasion in Madagascar will have disastrous impacts. One positive aspect is that so far this species has never been recorded as a carrier of the Chytrid fungus, Batrachochytrium dendrobatidis (Bd).

Unlike the majority of the world’s amphibian populations Madagascar has so far escaped the catastrophic declines associated with Bd. However Between 2010 and 2014, Bd was recorded in five different areas of the country, including Ranomafana, although the virulence of the strain is as yet unknown and no die-offs have been reported.

Boophis elenae

Boophis elenae

Boophis elenae

Boophis elenae

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Lemurs of Kianjavato

A few images of four of the Lemur species  I regularly encountered whilst in Kianjavato that I never got round to posting. Looking forward to getting some images of the Milne-Edwards Sifaka and Golden Bamboo Lemurs in Ranomafana NP although this might be more of a challenge as finding them could be a bit more difficult.

Enjoy!

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Eulemur Rufifrons  red-fronted brown lemur

Eulemur Rufifrons – Red-Fronted Brown Lemur

Eulemur Rufifrons  red-fronted brown lemur sleeping

E. Rufifrons sleeping fluffball!

Eulemur rufifrons  red-fronted brown lemur silhouette

E. rufifrons silhouette

Greater Bamboo Lemur (Prolemur simus)

Greater Bamboo Lemur (Prolemur simus)

Greater Bamboo Lemur (Prolemur simus)

Greater Bamboo Lemur (Prolemur simus) soaking up some sun.

P. simus having a nibble...

P. simus having a nibble…

A Greater-Bamboo Lemur doing what they are best at.

A Greater-Bamboo Lemur living up to it’s name.

Black and White Ruffed Lemur (Varecia variegata)

Black and White Ruffed Lemur (Varecia variegata)

V. variegata looking up from a nap

V. variegata looking up from a nap

Varecia leaping.

Varecia leaping

Varecia feeding on a Ravenala flower

Varecia feeding on a Ravenala flower

Varecia hanging out...

Varecia hanging out…

A big leap...

A big leap…

Black and White Ruffed Lemur (Varecia variegata)

Black and White Ruffed Lemur (Varecia variegata)


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First impressions of Madagascar….

One of the ubiquitous green Day-Geckos on a Ravenala palm.

One of the ubiquitous green Day-Geckos on a Ravenala palm.

The first thing that hit me about Madagascar was the level of development or rather the lack of it. For the drive from the capital “Tana” to Kianjavato I had mentally prepared myself, expecting to be shocked by the lack of forest. Whilst there were very few trees remaining until we got close to Ranomafana national park the thing that took me by surprise was the sheer number of people. Madagascar’s population is over 22 million people and it seemed like a lot of these were out and about, using the road to dry rice, transport goods either in baskets on their heads or in wooden carts and moving herds of Zebu cattle. Almost the entire drive was village after village of mud brick houses and wooden huts surrounded by banana plants and rice paddies. Even the small bit of Tana we saw by day seemed distinctly rural. Having been here a little while now I’m getting used to the hustle and bustle of Madagascar and hopefully there will be more images to come soon!

A Brookesia

A Brookesia “leaf” chameleon.

A juvenile rufi (Eulemur rubriventer)

A juvenile rufi (Eulemur rubriventer)

Vatovavy at sunrise taken from the camp site.

Vatovavy at sunrise taken from the camp site.

The most common frog around camp but one of the coolest!

The most common frog around camp but one of the coolest!

Greater Bamboo Lemur (Prolemur simus) living up to it's name.

Greater Bamboo Lemur (Prolemur simus) living up to it’s name.

Uroplatus!!!

Uroplatus!!!

A varecia in a typical pose

A varecia variegata  in a typical pose.


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Meerkats, Pups and a Puff Adder – a story from the Kalahari

Whilst sorting out my Kalahari photos (still an ongoing process!) I came across this sequence of images from one morning that I had half forgotten about. Looking back it was up there with the top wildlife experiences that year among the many that were had. I think it sums up a lot about Meerkats and would definitely have been worthy of a Meerkat Manor episode!

The morning started as every other morning had for 6 days a week for the last 10 months, i.e. waking up very early to arrive at the burrow of the group I was visiting before they got up and left for the day.

Juvenile dragging a pup from the burrow.

Juvenile dragging a pup from the burrow.

The first glimpse of a week old Meerkat pup in the middle of the frenzy.

A week old Meerkat pup in the middle of the frenzy.

Luckily the burrow wasn’t too far from the farm house and I knew the Meerkats would be there because the dominant female had given birth the week before. Meerkats generally change burrows every few days depending on the group and the territory (probably as a way to reduce parasite load). As each group was only visited by a researcher for 3 or 4 days per week if no one had been there the night before then you would need to radio track the group which could sometimes mean a much longer morning!

Meerkat pups stay underground and don’t emerge for 2-3 weeks until their eyes have opened and they are able to react to their environment a little. They then stay at the same burrow for another week or two just exploring the burrow entrance and the surrounding few metres. During this time the group generally leave 1-3 individuals to babysit at the burrow. Babysitters can be any individual in the group male or female but generally the dominant female doesn’t babysit and will often leave to forage with the group the day after giving birth. Some subordinate females start to produce milk and suckle the pups even if they have never been pregnant themselves.

Adult carrying pup.

Adult carrying pup.

The dominant female checking that the pup is being looked after.

The dominant female checking that the pup is being looked after.

On this particular morning I arrived at the burrow and sat down to wait, and waited, and waited. I was starting to get a little worried as if they had moved burrows it could mean that the pups had died or been abandoned. After a while I ran back to the farmhouse (only a 100m away) to get my tracking gear to check that the group were still at the burrow and sure enough I got a strong beep. This got me a little bit more worried as it would have been strange for the dominant male, who was wearing the radio collar, to have died overnight and the group to have left the burrow with or without the pups. I knew from the radio (we all had walkie-talkies to keep in contact) that all the other groups were up and had left long ago.

At about 3 hours after the usual time for this group to be up (the time each group gets up is usually very predictable with some groups consistently being late risers) the sunrise had long gone and it was starting to get hot, I heard noises coming from the burrow. It was a kind of spitting call which would usually be made if a Meerkat was startled suddenly, attacking a predator or fighting with a rival group. At least I knew I was in the right place and at least some Meerkats were alive.

“found another one!”

“it’s ok I’ve got this one!”

Suddenly the group emerged. Usually a group gets up casually one by one and they sit about at the entrance for a while to warm up before leaving but this time was different. It was a frenzy of meerkats coming up at different holes popping back down again, digging and anal marking (whenever meerkats get really hyped up by anything, especially the dominant, they scent mark with their anal glands).

After about 10 minutes of this activity I spotted a slightly purplish lump in the middle of the frenzy. It is very unusual to see a Meerkat pup this young and I had never seen one with almost no fur looking like that. At first I thought it was dead but I saw it try to raise its head. In the next 20 minutes they brought up two more pups and then another two, five in total!

Pups left alone in the confusion.

Pups left alone in the confusion.

And found again!

And found again!

All the pups were alive but they were being trampled, covered in sand, picked up, dropped, forgotten about and then found again. The action was frantic but luckily I had my camera so I was snapping away trying to capture what was going on. At some point I noticed the dominant females leg was badly swollen and bleeding. I still couldn’t tell what had happened but it wasn’t a usual morning! Due to the swelling I predicted that it was a snake bite and sure enough when I managed to get a glimpse down the burrow I saw the head of a rather angry puff-adder.

The source of all the commotion.

The source of all the commotion.

The group at that time had 4 juveniles which were almost sub adults who were all obviously very exited by everything that was going on and kept trying to pick up the pups which they could only just lift, moving them a couple of metres and running back to the burrow. This carried on for quite some time. Eventually the dominant female picked up one of the pups and made for the next nearest burrow, probably about 300 metres away! She eventually managed to carry all five pups to the next burrow almost by herself with a now massively swollen front leg whilst hindered by the overexcited juveniles.

All the pups survived their ordeal and so did the dominant female. Meerkats are very resistant to snake and scorpion venom and there are multiple Meerkats at the project that bear scars from snake bites, even on the head and face. Not all survive but many do. Later that week two of the males were captured for routine measurements and hormone samples and were found to have also been bitten however the dominant female must have taken the main hit of the snakes venom.

It was amazing to witness the strength and determination of that dominant female and I’m glad I took my camera out that day!

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The dominant female carried all 5 pups one by one!

The dominant female carried all 5 pups one by one on only 3 legs!

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Today I drilled through a frying pan! (DIY Ground Pod)

The completed ground pod with a wimberley sidekick and 120-300mm 2.8

The completed ground pod with a wimberley sidekick and 120-300mm 2.8

Another little DIY project that I have been thinking about doing for a while now. A DIY ground pod!

I got the idea from “The Handbook of Bird Photography” by Bence Mate, Jari Peltomaki and Markus Varesvuo which is a great book with loads of information about photographing birds. Normally I find these books are more for beginners and only cover the basics but this book has a load of detailed information. One of the ideas this book gives is to use a ground pod to get a very low angle.

The idea of a ground pod is that you can have all the flexibility of having a long lens on a gimbal style head much lower than any tripod with the lens being much more maneuverable than when using a bean bag. Also the smooth bottom allows you to slide your set-up along the ground as you crawl towards your subject, something that is a pain in the ass with a tripod.

When I looked up ground pods on the internet the cheapest of these cost around £80-£100 which isn’t bad for photographic equipment. However whilst looking at ground pods I came across a couple of people who had made their own and decided that Id give it a go.

Here’s how to do it:

Step 1: Drill a hole in an old frying pan.

Step 2: Attach tripod head!

That’s it! It’ literally took me 5 minutes!

I considered trying to remove the handle but actually it makes it easier to maneuver so I left it on.

I’m expecting some odd looks next time I turn up at a nature reserve with my camera attached to a frying pan but I’m exited to see how it works in the field!

The underside showing the standard tripod plate screw used to hold the tripod head on. I might tape over this to make it slide along the ground more easily.

The underside showing the standard tripod plate screw used to hold the tripod head on. I might tape over this to make it slide along the ground more easily.