Tuesday, 19 September 2017

Things that go bump in the night

Last week my trail cams batteries ran down. When I installed a new set the settings of the camera were reset meaning that the shots taken were single JPEG pictures this is not necessarily a problem, in fact, the photos actually give excellent quality shots of the animals captured by the camera.


However, I choose to take video clips as they help in identifying the species. You can pick up a lot about a species by how it moves and there is more chance of seeing other parts of the body as it moves through the field of view. This would have been immensely useful for two of this week's
shots.

Unknown Number 1: The Black Sausage

This shot shows a long thin mammal in the top right. I can say clearly what is not - it is not a badger, a fox, a deer. It is too big for any of the rodents, weasel or stoats. It could be a Mink or it could be a second visit for the elusive Polecat, either way, this shot is not good enough to say either way.

Unknown Number 2 - The Giant Rat


In this second shot, a mammal can be seen in the bottom right. The eye shine shows a pair of eyes forward facing and close-set. There is subtle evidence of a thin hairless tail. It seems to have larger hindquarters, my working assumption is that this could be a large rat, similar individuals have been seen occasionally over the years.

At the weekend I readjusted the camera to a hybrid setting which takes video and photos and hopefully both mammals will decide to show themselves again and be identified.


Sunday, 17 September 2017

Why are there barely any bears in Africa?

  
Recently my attention became drawn to an unusual natural curiosity; I wondered why there were no species of bear in Africa. Bears are remarkably adaptable and generalist species, they are capable of living in forests, grasslands and mountains. Their diet is omnivorous and on the whole wide-ranging across species. On the face of it, there seems to be no logical reason for the absence of this species from this continent. There are obviously no bear species in Australia and this is easily explainable. In fact, mammal fauna in Australia is unique. It is home to a unique marsupial assemblage which resulted from the split of the continent from the supercontinent Gondwana, its final separation occurred in the Mesozoic (251-140 million years ago) trapping primitive mammals on its shores. Africa, however, has a range of modern mammal taxa and niches indicative of the other continents.

Thus began a search of the literature to uncover the answer. The earliest mammals were small rodent-sized organisms and the lineage of the bear can be traced back to the Palaeocene species Cimoloestes before the origin of true carnivores and the development of carnassial teeth.

The distribution of the extant species of bears today. Note the lack of any bear species in Africa or Australia (Wikimedia Commons - Copyright Free)

Early bears resembled modern day Raccoon Dogs.
(Copyright: CC-BY-2.0 Mizunoryu)
The first true bears begin with Parictis a raccoon-sized mammal in North America which led to Amphicynodon and Cephalogale, a wolf-hound sized animal, found in 37 million-year-old Chinese deposits. Radiation of the species led to Phobercyon, Pithocyon and the aquatic bear Kolonomos.

Modern bears (Ursidae) exist in three sub-families Ailuropodinae, the Giant Panda, Tremarctinae, the Andean Bear and the Ursinae, all other bears. These three lineages common ancestor was Ursavus elmensis. This species lived 20 million years ago; they originated in Asia and spread to North America. They were about 30 inches tall, adept climbers with distinctive omnivorous teeth and probably similar to modern-day Racoon Dogs.


The Giant Panda was for many years a subject of debate concerning its ancestry and growing up I can remember it not being listed as a bear, today, however, it has been shown that the Giant Panda descended from Ailurarctos which lived in Yunnan Province in China 7-8 million years ago, it too had links to Ursavus.

The Giant Panda was considered separate from the bears for
many years. (Wikimedia Commons - Copyright Free) 
The Tremarctine Bears (also known as running bears) evolved during the middle Miocene as the world became drier. The humid forests were replaced by temperate forests and scrubland. These species became more specialised carnivores and became larger in body size. They first dispersed into North America and then when the Panamanian land bridge surfaced 2 million years ago into South America. Key running bears were the 600 kg Short-faced Bear (Arctodus simus) and the 400 kg vegetarian Florida Cave Bear (Tremarctos floridanus). These two species were remarkably successful surviving up until only 10,000 years ago. The Tremarctine bears faced increasing completion from big cats and the late Pleistocene extinction of the large herbivores. Their extinction also matches the appearance of mankind and arrival of Ursine bears such as the Brown Bear. Today only one Tremarctine species remains the Spectacled Bear of South America.

The Short-faced Bear (Arctodus simus). (Copyright: CC-BY-SA-3.0)
Asiatic Black Bear (Ursus thibetanus)
 (Copyright: CC-BY-SA- 4.0 Rhealopez168)

Ursine bears evolved from the Little Bear, Ursus minimus, they evolved 5 million years ago but underwent great change and radiation during the Ice Age 2.5 million years ago. Rather being large and fast the bears in Eurasia became slower and predominantly omnivorous. The little bear spawned the modern bears (Sun Bears, Sloth Bears, American Bears, Asian Black Bears, Brown Bears and Polar Bears). The Little Bear most closely resembled the Asiatic Black Bear (Ursus thibetanus). It spread right across Europe and Asia becoming isolated in Asia during the Pleistocene.



Brown Bears split off from the Little Bear 1.2-2.8 million years ago although there is some evidence they could have split from the Etruscan Bear or the Cave Bear (Ursus spelaecus). The Etruscan Bear led to the Eurasian Cave Bears 500,000-100,000 years ago. They were large (400 kg) and similar to their American Florida Cave Bear cousins. The Cave Bear had a distinctive domed forehead and weighed 500 kg; it vanished in the late Pleistocene. Regardless of the exact ancestor Black Bears and Brown Bears separated at this time as part of a massive radiation of species which somewhere included the Sloth Bears and the Sun Bears. The Brown and Black bears spread across Europe and Asia, crossing the Bering land bridge to colonise North America.
The most recent species to evolve is the Polar Bear that evolved from the Brown Bear lineage some 200,000 years ago. This specialised polar hunt is exclusively carnivorous whilst the Brown Bear retained a generalist omnivorous diet.

The huge Cave Bear (Ursus speleacus).
(Copyright: CC-BY-SA-3.0)

In this discussion, it is possible to see waves of bear evolution occurring in Europe, Asia and the Americas. Climatic changes and the creation of land bridges led to a dispersal and radiation of the species across the major continents. In this story, the Tremarctine dominance in the Americas gave way to a Pleistocene invasion of Eurasian Bears it is clear that Africa is not mentioned at all. This indicates that whilst the species proved adaptable to most continents something restricted their spread onto this particular one.

Whilst I claim that there are no bears in Africa there is, in fact, evidence that they had been. Atlas Bears (Ursus arctos crowtherii) lived in North Africa and were a sub-species of Brown Bear. They covered much of Moroccan, Libyan and Tunisian mountains and forests. They had slightly more orange fur and a shorter face more reminiscent of their Miocene relatives. It is believed the Atlas bear was hunted to extinction, first by the Romans who used them for sport in their coliseums and later by other hunters. The last Atlas Bear was killed in the 1870’s.

Fossils bear remains have been discovered in two locations in Sub-Saharan Africa; South Africa and Ethiopia. These bones relate to one of the ‘running bears’ from the late Miocene and Pliocene. The species, Agrotherium africanum, had primitive teeth and was probably primarily herbivorous and a scavenger it is thought the genus became extinct from competition. This paragraph, I think, holds the key to why there are no bears in Africa, Competition and the Sahara.

Much of the evolution of the bear occurs in either Asia or North America with the resultant species spreading out in either direction east and west. In the Americas, the species were able to radiate south once the Panama land bridge was established and today we still have bears along the Andes. In Asia the Panda thrived in the bamboo forests, the Asiatic Black Bear across south-east Asia and heading southwards the Sloth Bear appeared in India. We know bears existed along the Atlas Mountains north of the Sahara desert but none south of it. It is likely that like for many species the desert acted as a considerable barrier to the southerly expansion of the bears. This barrier stopped the colonisation of Africa by any of the modern species of bear in the past 1 million years.
The only surviving Tremarctine Bear
- The Spectacled Bear/Andean Bear (Tremarctos ornatus)
(Wikimedia Commons - Copyright Free)

As we now know there were Cave Bears found in Ethiopia and South Africa but they evidently died out without spawning new taxa, this suggests competition coming into play. To explore this we must look at the evolution of the Order Carnivora as a whole. This line includes all mammal carnivores which appeared in North America 42 million years ago from Miacids. This order very quickly splits into two orders, the Caniformia and the Feliformia. The Feliformia included all the Cat families and were predominantly successful in Africa and Asia whilst the Caniformia that included the dogs, arctoids, racoons, weasels, seals and bears were most successful in North America, radiating into Europe.

Therefore the bear lineage became a mostly northern hemisphere line that was unable to successfully spread south through Africa and those that did found themselves out-competed by the dominant feliformia predators like the big cats. Today where there are bears or dog species there are fewer cat species and vice versa.

This is not a watertight explanation but I think draws together the ancestry of the bear along with biogeographical information. With modern taxonomy and the development of improved genetic testing evolutionary theory is coming on leaps and bounds and every year a better picture is gained. There is still much to be discovered and for that, we need both the paleontological evidence and DNA sequencing.

Bibliography

Bears of the World http://www.bearsoftheworld.net [Accessed: 16th September 2018]

Benton, M.J. (2015) Vertebrate Palaeontology. 4th ed. Wiley Blackwell. Oxford.

Macdonald, D. (1992) The Velvet Claw. BBC books. London.

Prothero, D.R. (2017) The Princeton Field Guide to Prehistoric Mammals. Princeton University Press. Oxford.

Wilson, D.E & Mittermeier, R.A ed. (2009) Handbook of the Mammals of the World. Vol. 1 Carnivores. Lynx Edicions, Barcelona.


Sunday, 27 August 2017

BBC Wildlife Magazine Retrospective

The BBC Wildlife Magazine is one of those British institutions like David Attenborough himself that inspires confidence, respect and quality. I first began reading the magazine in 1991 aged 13, back then the magazine was very different to the one we see today. Some part of me misses the more direct and harder style of that earlier age. Today’s issues remain of excellent quality but there is a subtle feeling that within its glossiness some of its scientific edge has been lost.
The first issue I bought

Since that first issue, I have collected and read nearly every single issue. For some time I kept them stacked beneath my bed before several years ago when buying a new bed I realised the futility of keeping them all. With great effort, I abandoned my older issues keeping only those from 2004 onwards which I put into binders and added indexes.

Today after my usual Sunday nature watch on my patch I stopped at the pub for a cool drink and sat on the terrace reading the latest issue. It was whilst reading this that I thought about something that has been on my mind for awhile. How much of what is happening in nature today just the same as in the past, have we made progress? Are the problems today the same as yesterday or are we facing a whole new set? Either is not a particularly heartening prospect for different reasons.

Following up on this thought I pulled out my earliest issue I still had and started to compare it with the latest one. The issue in question was from January 2004, it was priced £2.90 and had the image of a Scottish Wildcat on the front. The issue included a free gift of a Pocket Guide to Pebbles. The editor back then was Rosamund Kidman Cox who edited the magazine for a few months more before publishing passed to Immediate Media and Sophie Stafford took over the editorial chair.
2004 Issue

Much of the magazine is recognisable there were sections on highlights, discoveries, letters, news of the earth and tales of the bush and a wide range of in depth articles and opinion. In the highlights there was a small piece on the rise of the Buzzard; it stated that Great Britain was now home to 50,000 pairs; today that value is more like 70,000 pairs. Richard Mabey’s regular column discussed the US Wildlands Project that extolled the three main tenets of Reconnect, Restore and Rewild. The first two I remember being important factors in the early 2000’s my own thesis in 2001 was concentrated on metapopulation theory and habitat fragmentation, and rewilding has been growing a pace in the last 10 years.

Sadly not everything has changed; this month’s article on Black Rhino conservation in Samburu, the species is still in as much danger now as in 2004 especially as new laws in South Africa now allow the domestic trade in rhino horn. Many of the 2004 issues articles still have a resonance today; Chris Baines discussed the plans to merge English Nature with the Countryside Agency and Rural Development Service. Such plans did, in fact, come true with Natural England being born some two years later. This body continues to operate today; I will leave you to decide if it is better or worse than what came before.

Interestingly the following issue (February 2004) had an article on the Badger Cull Trial which had begun in 1996, this counterpoints this month’s article on the latest Scientific findings on the bTB and Badgers. In 2004 the Krebs trial was still running and all the questions raised now were being asked then, in fact, the article ends with this now somewhat sad sentence – “maybe the authorities will realise that culling is a response out of all proportion to the threat posed by badgers to our food industry”. Even then there was scepticism as it was pointed out that then 70% of DEFRA’s TB programme was spent on badger control rather than cattle protection measures. Today we are still a year away from the end of the proposed cull cycle, more and more areas have been added to the cull zones and the science remains to show that controls in animal husbandry and control have more affect than the bTB reservoir in natural populations, same old, same old.
This months issue - available from all good newsagents


To close on a lighter note I cast a gaze over the listings pages and recalled fond memories of halcyon days during which Big Cat Week was on the TV, Countryfile remained at 11 am on a Sunday morning and Nature still broadcast on Radio 4. The BBC’s Natural History Unit also reviewed in this month’s issue has gone from strength to strengths and continues to push the boundaries of technology and knowledge, the programming today is as epic as it ever was and the BBC Wildlife as a magazine is the same. Whilst I may feel there the magazine has lost some of its hard edges, this is no bad thing, the magazine is more inclusive and representative of the wider community and has increased its reader involvement with more questions, activities, their photographs and its local patch reporters project. Long may the BBC Wildlife continue and as long as it does I will be subscribing.

Sunday, 20 August 2017

Rewild: The Art of Returning to Nature - By Nick Baker

In recent years my understanding of nature conservation is shifting. It is being moved by a growing groundswell that seems to postulate a new approach. The old movements of the 1980's and 1990's for nature conservation with neat heavily managed nature reserves protecting a collection of core species is starting to make way for larger ideas surrounding ecosystem services and rewilding.

A brand new approach to conservation and its relationship to society seems to be entering gestation and it is unclear if this still a rather nebulous idea will grow and flourish or arrive, forgive the imagery, stillborn.

The concept of rewilding has been of immense interest to me since I first read about the reintroduction of Wolves to Yellowstone National Park in the US. It led me to read the excellent book, Feral, by George Monbiot back in 2014 and reviewed here on this blog. So it was with some interest that I saw a review of a new book in the BBC Wildlife - ReWild: The Art of Returning to Nature by Nick Baker.

Nick Baker has always been a favourite presenter and ecologist of mine. I remember him from his time on the Really Wild Show and have loved many of his many series. His love of all kinds of creature is instantly relatable and his enthusiasm, knowledge and passion shine out brightly. I quickly ordered the book and finished it today.

To start off I must confess the book wasn't exactly what I was expecting. From the title, I assumed there was more information on the case studies of rewilding and the natural approach to nature conservation and this was indeed referenced but it wasn't the main thesis of the book. Nick used rewilding as an 'in' to discuss firstly how detached how we as animals are detached from the wild life around us and then to reintroduce us to them by taking us step by step through our five senses and explaining how they can be tuned or rather re tuned to nature.

He extols the virtues of silence, the night, walking, tasting, hearing and listening; and yes listening and hearing are two different things. As I worked through the book some chapters resonated better with me than others, but Nicks charm filled style of writing carries you along and his anecdotes and personal accounts colouring each section. It got me thinking that an autobiography of his travels would be interesting as, if you count up the countries he mentions throughout the book you'll very nearly have the full UN membership. In fact, I cannot find an autobiography but hope fervently that one day he will catalogue his experiences.

The book overall then despite not being what I expected was a joy to read for the most part. It is more a  book for a dabbler in conservation or perhaps for those that have completely lost touch with their wild side rather than an expert or experienced nature lover. Nevertheless, it encouraged me to sit more and watch and has some excellent ideas for improving fieldwork.

You can buy the book from all good bookshops - and Amazon

A Moorhens Tale

Autumn is starting to show its hand, the Robin's song has changed and there is a different quality to the air in the morning. Bird-wise we have entered a lull between the seasons. The Saxon Mill was remarkably quiet, a lone Chiffchaff sang its song and the Whitethroats have all left for Africa and in the skies, the Swallows were starting to gather in swooping clouds.

Adult Moorhen

Sat beside the river waiting for the Kingfisher to show I found myself watching a juvenile Moorhen. At this time of the year, they have lost the cute a cuddly black fluff and are now something of a drab black and brown bird. It pottered along the edge of the water in a skittering careful manner, it was joined by a second and I heard a third unseen to my right. I began to think about how successful this bird actually was on my patch, more so perhaps than the other ubiquitous waterbird, the Mallard.

Mallard are common on the river; more so in the winter than the summer when they pair up to mate. However, ducklings last only a very short time on the river. Each year I see one maybe two broods and they rapidly diminish. 1st Year juvenile survival is 0.518 and appears much higher on my patch. The river is a dangerous place for small nestlings, struggling to survive to fledging. Under the water the river is teeming with Pike whilst above ground there are two pairs of foxes in the area, Mink frequent the area and Otter have been seen as well. They are not safe from their own kind either, Kestrels and Sparrowhawks are common on the site, but these are unlikely to present to much of a threat instead their avian foe is the Grey Heron. All these predators would make short work of either a duck or moorhen chick but it seems that Moorhens at least have a greater survival rate on the river.

Mallard with large brood at the mill, most of these ducklings won't make it another week


Mallard clutches tend to be larger than Moorhen and their food sources and predators are the same and yet the Moorhen seems to do better. This could be due to the ability of the Moorhen to have two broods compared to the Mallards one. This would certainly boost numbers and aid survival but whilst watching the juveniles I began to think that perhaps behaviour and morphology have a part to play.

Moorhens are more cryptic in behaviour than Mallard, yes females have excellent camouflage but once hatched the young are more vulnerable for longer. Newly hatched chicks of both species are highly vulnerable in the first couple of weeks but as they grow the ducklings remain more vulnerable. The Moorhen juveniles become more mobile, they are more wary on the water and faster on the land. They skulk in the shadows instead of being visible on the water. At the Saxon Mill where there are abundant predators it is the Moorhen that has greater flexibility in both hiding and evading predators and so their breeding success is greater.

Moorhen with Chick - less than a week old


If you compare the breeding on the river to that on the canal survival between the Moorhen and Mallard is more even with many more ducklings evident and predators are fewer.

It’s interesting how even the commonest of birds can have such interesting lives.

Sunday, 13 August 2017

Recent Camera Trap Sightings

With the change from my old Bushnell Camera Trap to the newer version, I have lost several weeks of data and I am still trying to obtain the best location height for it. At the moment the field of view on the new camera is smaller than the old one and so does not catch the animals quite as well as it used to. Tomorrow I am going to attempt lowering it a bit although this does present a risk...

On the whole, the animals are used to the camera as it is, they rarely concern themselves with it although occasionally making eye contact. Occasionally, however, some animals will take an interest a prime example occurred this week when an unknown animal, possibly a badger took a good sniff of the camera.

video

Still on Badgers, this week their activity increased a little and a possible cub was sighted. An interesting clip, shows a badger using its incredible sense of smell to locate food underground and then use its powerful claws to excavate the prey. It follows up by marking the site.

video


video

In other clips Half-Tail the Fox made a single appearance and 3 separate muntjacs have been identified. A small youngster, a full grown female and a full grown buck. All were seen separately and represent individuals, they are possibly a 'family' that post breeding have gone their separate ways.


video

Young Muntjac

video


Hind


video

Buck

Sunday, 6 August 2017

The Beauty of the Small Copper

In the past couple of weeks, I have seen several Small Copper butterflies. They are deceptively small butterflies that are in the middle of their second flight period of the year. Whilst, not a rare species nationally I rarely see many each year and each sighting is a treat if you can wait long enough for one to land.

Like many British butterflies, their predominant colour is orange. They have striking speckled patterns on the fore wings and a beautiful band of orange on the edge of the aft wing.


This individual was probably newly emerged as its colours were still vibrant and the wings were perfect with no scale loss. Eggs are laid on dock plants and it is on this abundant plant that the caterpillars feed.

The beauty of the species can only be seen when settled.


Only then is it possible to see the gently striped black and white antennae ending in a black top dipped in yellow/orange.   Close up you can see that the majority of the butterfly is chocolate brown punctuated, like the orange, by black spots. A frill of fine silvery hairs edge both sets of wings.