Thursday, 12 February 2009

The CFZ solves another mystery!

And then, as if by magic, just when I had finished writing the previous blog, I got an email from a contact from the local news who said “One of our readers e-mailed me these this am. I’ve had a long chat with her and she is convinced they are a big cat’s prints. She heard a big “kerthump” as if it was jumping down. She has fields and woods around her and just three houses up there. Lots of deer in the fields. She is on the Cranmore side of Doulting. I said I would pass the photos on to you to see what you think. Her details are below and she is happy to talk to you. I have sent her copies of the stories we did as she had not seen them.”.


Attached were two photos, one showing the print, and the other showing the stride length. They looked pretty damn canine to me, but for a second opinion (always important) I passed them (again) on to Richard Freeman, who had this to say:

"These are clearly dog tracks. The concave shape of the main pad can be seen in the first photograph. Also, the toes are symmetrical and show the blunt claws of a canid. A cat's claws are finer and only seen in prints when unsheathed for a firmer grip on slippery or uneven surfaces. A cat's main pad has three bulges or lobes akin to the shape of a club in a deck of cards. The toes on a cat are asymmetrical unlike a dogs."



I don’t think I can add anything to that! Never mind, at least the CFZ now has a very good photo of what a dog’s print in the snow looks like!

I did have chat with the person who took the photos, and the fact that she lives next to a field in which a few dogs are walked closes this case. Apart from one thing: “She heard a big “kerthump” as if it was jumping down.”. This does sound a bit odd, until you realise that the prints were in her garden, and to escape the dog would have had to jump over the fence, creating the “kerthump” noise. Case closed.

But, the journalist who sent me this case also mentioned that she is “trying to check out the report from the lady from Cranmore who was saying she heard something big snarling in the bushes near her home last month.”. Now, as you can see, Cranmore is very close to the place where the lady found the dog prints. Naturally, I will keep you updated.

Wednesday, 11 February 2009

Cat prints? Not again...

It is now time to update on the hunt for alien big cats in the UK. Last time, you will remember I was told by a member on an invertebrate’s forum that her boyfriend had taken a cast of the print of an ABC, or so her other half’s mate said, in their local area. Naturally, I asked; “where is it now?” and the reply was “I don't think he has the cast anymore”. “Bugger!” thought I. Never mind, she sent me a link to a photobucket account where there were photos to look at instead. They looked like a good match for a cat to me and the size was well within big cat range. After forwarding them to Richard Freeman, I emailed Hollie, as her name turned out to be, who gave us permission to use the photos, and it is to her that I am very grateful for otherwise this extra evidence would not have come to light. The best photos are shown below.


Also, she said that her boyfriend (Dan) had “actually seen the cat one night when hunting up there, though it was it dark he says he remembers seeing a big pair of eyes, too big for any "normal" animal, and looked orange coloured apparently.”.

Now, it is time to explain this eye shine business. Eye shine is, obviously, caused by light entering an animal’s eye, reflecting out of the animal’s eye and then entering our own. The shine effect is from a layer of tissue called the Tapetum lucidum which is found in many vertebrate animals. Its function is to reflect light into the light sensing cells (Rod cells) in the eye to enhance night vision further. So, when a light is shone into an animal’s eye, you quite often see it shone back at you from their eyes as the light escapes from the lens and through the pupil. Carnivores possess a choroidal tapetum cellulosum which is made of reflective crystals, whereas artiodactyls and perissodactyls have a choroidal tapetum fibrosum made of extracellular fibers. So, these two different reflective layers give different eye shines.

Eye shine varies between different animals, but it is not an exact science. Cats usually have green eye shine (domestic), as do deer, but dogs can vary from green to yellow and to orange, depending on breed. However, a number of reports say that big cats like leopards have orange eye shine, which completely confuses the matter! I must say this subject has been hard to research; everything contradicts everything else!

Then, as if this wasn’t good enough, Hollie spoke to her boyfriend, who said that his mate still had the cast, and that we were welcome to have it for a bit! This is excellent news, so we will have to sit tight and wait for Pat.

In the mean time, Richard got back to me to say this:

Though I will reserve final judgement until I have actually seen the cast my initial feelings are that these are indeed cat prints. The toes are asymmetrical and lacking in visible claws. The central pad lacks the concave shape of a dog’s .The toes also appear to show greater flexibility than a dog's.”

He attached the following photos; the uppermost photo is of a leopard, whilst the other is of a puma’s print.




Now compare these photos to the cast photos above. Richard says:
It could belong to a puma or leopard but I think it is most like a puma's with the wide toe pads. In fact the print reminds me of a Florida puma print I saw that had been cast from a track left in sand.”

I agree with him, but also the central pad in a puma is more compact than a leopard’s, very similar to the print in the photo.

For a further analysis, we will have to wait for the print to be delivered. Watch this space with bated breath! But may I just say again how grateful I am to Hollie for letting me look at the photos and for doing her best to help find the cast. If only everyone came forward with evidence!

Monday, 9 February 2009

UK ALIEN ANIMALS STUDY GROUP: Never outfox a fox

There seems to be a theme running threough the CFZ. After Beth's post about her pet fox Millie, we had Tim’s post on urban foxes, Dr. Holdsworth’s post on their biology, and now we have me looking at a very interesting alien animal indeed, the wily fox.

Vulpes vulpes is the UK’s local fox. The genus contains 12 species who are to be found on almost all continents (Antarctica is, as usual, an exception) and they all fill the same role: small adaptable carnivores who are adapted to eating any animal from the size of a typical insect, right up to a large game bird or lagomorph. Foxes moved up from the land bridge from Europe into the UK, but they never got up to the small islands off the coast of Scotland. However, it seems they may well have found a way.

Thanks to the very helpful Glen Vaudrey, (soon to be CFZ Cheshire rep) we have the news that it looks like the red fox has found its way to the Outer Hebrides. Although no reports have been certified by Scottish National Heritage, between December 05 and January 07, with 2 reports before this, 12 reports of foxes have been reported. These come from the Islands Lewis, Harris, Benbecula, and South Uist. I did try to upload an image of the area, but it was too small to see the Island's names, so I have not. But, the reports nearly span the entire area of the Outer Hebrides, from Lewis in the north to South Uist near the South. The sheer span of reports is what settles this matter for me; we have sightings of adults, sightings of cubs, 2 reports of droppings, a dog who acted strangely in response to smells, and finally, that a fox was seen for 15 minutes by a professional mammal biologist. The reports I was sent are repeated below:

Dec-05 Tolsta, Lewis = Report of fox seen on croft
Dec-05 Gress, Lewis = Report of glimpse of fox by road side
18-Feb-06 Urgha, Harris = Report of fox watched for 15 mins by professional mammal biologist
2005 Barvas road, Lewis = Note on local paper about someone seeing a fox cross Barvas road
2005 Clisham, Harris = Letter in Stornoway Gazette reporting seeing fox cubs beside a loch
28-May-06 Tong, Lewis = Report of fox seen in garden
May-06 Galson, Lewis = Report of fox droppings, and a dog behaving in a strange manner in response to smells
06-Jun-06 Daliburgh, S Uist = Report of fox seen crossing road in the evening
06-Jun-06 Liniclate, Benbecula = Report of fox
27-Jun-06 Tolsta, Lewis = Report of fox droppings by Garry Bridge
Aug-06 Uig, Lewis = Seen on road somewhere between Gisla and Grimersta
31-Aug-06 Arnol, Lewis = Seen near fish farm
Dec-06 Gress, Lewis = Seen on a croft
Jan-07 Aline, Lewis = Fox seen in trees by the road

This is a lot of reports, most of which seem viable. As one would expect from foxes, there are reports from a number of different areas, notably including a garden (typical!). 10 of the reports predictably come from the largest Island, Lewis. Now for the real question, how did they get there?

Tough to answer that is. If this was a geological report from 3 million years in the future, and we were looking at fossils not live animals, we could confidentially say that they got to the islands by using the sea as a vector and were washed out to sea, possibly via a flood, where their swimming and the action of the current swept them over to the islands.
The distance from the Inner Hebrides to the Outer Hebrides, is about 25kms, not too far for animals to be swept. This may have taken a few days and a lot of luck, but the fox may well have got there still breathing. Thin, but alive. All it would take is a male and female to be washed up within a few years (their lifespan is only about 3 years in the wild) and you probably have a breeding population. Better than that, a pregnant female is washed over and then you have multiple foxes.

However, we are not dealing with geological time; this is “real” time. I am not so sure that this a long enough period of time for this theory to work, although we must not dismiss it. It seems that humans are a more likely vector, either deliberately or by accident. They could have been released by someone bringing a few over from the mainland, or in the hold of a ship. I am really not sure what to make of it! David MacLennan from Scottish National Heritage says “It’s very difficult to say how they got here, because we don't even know if they are here!” and I must say I agree with him in the main. It seems highly probable that they are there, but more evidence is required. Photos however, are to easily faked by photographing a fox from the mainland, so a pinch of salt may be required if one comes to light.

WIKIPEDIA FACT FILE: Today, the Red Fox has thje widest range of any carnivore - range spanning most of North America and Eurasia, southern Australia, and with several populations in North Africa. In Australia the Red Fox is an introduced species and a serious conservation problem. Introduction occurred about 1850, for recreational fox hunting, In North America the Red Fox is native in boreal regions, introduced in temperate regions. There is a recent fossil record of Red Foxes in boreal North America, and one subspecies of these native boreal foxes extends south in the Rocky Mountains. In temperate North America, Red Foxes are derived from European Red Foxes, which were introduced into the Southeastern United States around 1650-1750 for fox hunting, and from there to California for the fur trade. The first introduction is attributed to Robert Brooke, Sr., who is said to have imported 24 Red Foxes from England. The introduced European Red Fox may have interbred with the scarce indigenous population to produce a hybrid population.

Three subspecies of Red Fox are found in India: Vulpes vulpes montana (the Tibetan Red Fox), found in Ladakh and the Himalayas, Vulpes vulpes griffithi (the Kashmir Fox) found in Jammu and Kashmir less the Ladakh sector, and Vulpes vulpes pusilla (the Desert Fox) found in the Thar Desert of Rajasthan and in Kutch, Gujarat. A subspecies, the Japanese Red Fox (Vulpes vulpes japonica) migrated from India to China and eventually to Japan.




Wednesday, 4 February 2009

Californian Condors gain 2.37% boost to numbers!

I heard recently that in a public release, 4 captive bred California Condors (Gymnogyps californianus) will be sent out to join the 67 wild condors in Arizona. This is a welcome boost to the species’ wild population, which currently numbers 169 spread across 3 states plus that rough number again in captivity. Before being re-introduced to Arizona, the species had suffered a massive decline across the US. This is mainly from hunting, disturbance by tourists and air traffic, and from pesticides. The numbers had dropped to 20 birds in the 80s, and now a strong captive population is producing young at a steady rate. Steady that is, for a bird which takes 6 years to mature, lays one egg at a time, breeds every other year and can live for just shy of 60 years (although this is usually between 40-50).

In the event that you do live in California, you can take Highway 89A from Kanab or Page to the Vermilion Cliffs (from Flagstaff take Highway 89 to Highway 89A) before turning north onto BLM Road 1065 (a dirt road next to the small house just east of the Kaibab Plateau) and continue about 2 miles to get to the Vermilion Cliffs Monument. The event starts at 1100 on the 7th of March.

Now, condors (both species) are new-world vultures, family Cathartidae. There are 7 living species split into 2 groups: the turkey vultures, black vulture and Californian condor (essentially, it is a giant turkey vulture) make up one group, whilst the Andean condor and King vulture (a stunning animal) make up the other group. The first group lives in North America, and the latter group is from South America. So, although they are only slightly related, if I refer to condors, please take this as both the Andean and Californian species.

During the Pleistocene epoch (1.8m-10,000 years ago) this species was very widespread, covering most of the Americas. There were two other members of the Gymnogyps genus, but these became extinct before man arrived. There was one sub-species of G. californianus; amplus which lived across America, even down into Florida. This sub-species was a bit larger than today’s, being about 2kg heavier on average, with a larger bill. Since the Holocene began (10,000 years ago to the present), the Californian condors range contracted and became increasingly inbred. Now, those who know their geology and paleontology will know that about 10,000 years ago, much of Americas megafauna died out, either as a result of human activity, or a massive climate shift, most likely a combination of both. Species which died out in America at this time include a number of species of elephants, dire wolves, short-faced bears, giant long horn bison, the glyptodonts, four species of giant ground sloth and saber-toothed cats. Now, after this extinction, surviving species increased massively in number, most notably the current sub-species of bison.

The Californian condors did not cope well with this huge extinction, and they reduced in numbers massively. Other larger relatives of condors (family Teratornithidae) died out with the megafauna (or did they? But that is for another day). All large birds need near perfect conditions with lots of hot thermals to soar upon, lots of food and water and little competition. Even 500 years ago, it was spread across the American South West. The Californian condor is known to kill small animals. This is probably a recent trait as its relative the Andean condor (Vultur gryphus) does not do this, so it may well be an adaption to new areas where it had to kill to survive. In my opinion, this species has been reduced in numbers somewhat by human persecution, but mainly because it is a scavenging bird that eats the carcasses of large animals. It could probably have struggled on and found new food sources from the massed numbers of bison, but the 19th century extinctions destroyed any hope of that. It seems to me that the Californian condor was a species doomed to extinction. We have however, saved it. Its numbers are rising, but the day will come when its concentrations hit a maximum. It will probably be a very low concentration: their food source is very limited in number. We are now just prolonging its eventual demise, but why?

I think that as long as people who give money to the charities which are keeping it alive, the people who do so much volunteer work to help the species and the people as well as the people who manage the companies and government departments who are instrumental in this task know that this is a species doomed to die without our help. Assuming we stopped helping it now, it could be extinct in only 1000 years (please remember, we are talking geologically here, human life spans are too short to talk about the natural world in) which is no time at all. But it is a stunning bird, the second largest flying bird in the world that lives in a fairly accessible location. I myself have seen these birds in captivity, and seeing this bird flying in its aviary was unforgettable. The sight of the 10’ wide wings, black with a white flash, propelling that massive body up into the air; its muscles straining before it could soar and down onto its perch. Now, imagine seeing that in the wild, somewhere where it wouldn’t run out of flying space, somewhere where it can live its life free without needing to be surveyed, checked upon and helped constantly by us.

That is what we should be aiming to do, get the species to a stable state (which doesn’t mean 1,000,000 of them in the wild, 330 as we have at the moment is fine) and within a small area so it can breed easily. We stick a perimeter fence around the area to prevent egg thieves (admittedly, this is the only area we should be helping, the low lives that are egg thieves could love a condor or two) and put up watch posts where people can observe them. Leave them alone to live their lives, stay out of their way and don’t disturb them too much. Condors often break their eggs after being disturbed or being frightened: the eggs can roll off the nest whilst the huge adult moves to look at the potential threat. We get rid of these daft tags they have on at the moment and let them be properly free. The species has bred in the wild recently, so they can do it without our help. The conservation of these animals has cost $35 million, so let’s quit whilst we are ahead, and move on to saving something else. The species will survive for a while before reverting to its natural progression and becoming extinct; it’s incredible temperature tolerance (0-40 degrees C) and longevity will see to that. We ourselves are probably doomed to die only a few hundred years, but if we see through that we as a species will die out for the opposite reason as the Californian condor: we will die out from over population.

Monday, 2 February 2009

Possibly the strangest bats ever...

There has been much discussion about New Zealand bats on the CFZ blogs in the last few days. Jon wrote something off-the-cuff about wishing that a certain long-extinct species of New Zealand bat was still in existance. This got me thinking. What was it? Why did it die out? and could it have survived?

New Zealand has been home to three species of bat within living memory. The two species left alive and in a reasonably stable state (well, their numbers have been reduced dramatically, but they are not in danger of extinction yet) are the lesser short-tailed bat (Mystacina tuberculata) and the long-tailed bat (Chalinolobus tuberculatus). But, there was another species, the greater short-tailed bat (Mystacina robusta) which, at 90mm in length was New Zealand’s largest bat. It became extinct in 1967, leaving only one photo of its species taken in 1965. However, it seems someone forgot to tell the bat.

The Short-Tailed Bats are a funny group, being from the family Mystacinidae, and are endemic to New Zealand. The Greater had a large distribution over the northern climes of the island which is known from sub-fossil bones. It was classified as a sub-species of M. tuberculata until 1962 when it left the other 3 sub-species of M. tuberculata to form its own species. Greaters did the job of small rodents on the island, moving on the floor with all four limbs and only flying when necessary. Lessers are slow flyers, rarely getting above 3 meters above the ground, so it is expected that Greaters, with their larger body size, could only live in the north where the temperatures were high enough to allow them to warm up and fly (all Mystacina bats allow their core body temperature to drop at night, so when they want to become active again they need to become hot). Below is the only photo of the greater short tailed bat.




Now here we have an interesting example of an animal going against Bergmann’s Rule (within a group of closely related animals with a large north-south range, species/sub-species nearer the poles are larger). This rule works for “normal” homeotherms (constant body temperature), but here the advantage of keeping the core temperature high by having a large body to retain heat (lower surface area to volume ratio – better heat conservation) is outweighed by the time it takes for the body to heat up again in the day; thus we have small bats nearer the pole, and larger bats further toward the equator.
I expect you are now thinking “How on earth did this bat keep its wings out of the way whilst it foraged?”. Very good question: both species did so by tucking the wing membranes under a different membrane on their body, leaving the bats to scurry around in and out of burrows and about on the forest floor as eagerly as a mouse. The illustration shown opposite shows the bat as it would probably have stood, with its wing folded out of the way. They were most likely insectivores like M. tuberculata, but this is not known for certain.





So, why on earth are they gone? Well, New Zealand is one of the countries hardest hit by human intervention, and when rats were introduced to the mainland the short tails were in danger. Habitat destruction began their decline, and very soon rats followed and decimated the local wildlife. Soon, the greater short tail was gone from the main land, surviving only on Big South Cape Island. Then, tragically, rats got to the island from a ship. The populations of South Island saddlebacked wattlebird, Stead's bush wren, Stewart Island snipe and greater short-tailed bat were all but wiped out within the space of a few years. Only the saddleback was saved and is still alive, the other three unique species were gone for ever.


However, the IUCN continue to list Mystacina robusta as Critically Endangered as apparently “recent, unconfirmed reports of bats from this small island [Big South Cape] and a neighbouring island, however, could be this species”. The current evidence for this apparent survival extends to “several reports of bat sightings from Putauhina, and in 1999 Colin O'Donnell recorded Mystacina-like echolocation calls from the island that do not belong to M. tuberculata (O'Donnell 1999). There have also been two unconfirmed reports of bats being seen on Big South Cape. The identity of the bats being seen still must be confirmed” because it could have been one of the two other species. However, the long-tailed bat lives 50km away, which is probably a little far as it has not been recorded on the island before. It was listed as Extinct in the most resent revision in 1996, before being changed to Critically Endangered in 2008.

Sunday, 1 February 2009

The launch of the UK Alien Animals study group

Hooray! A new venture for both the CFZ and for its shortest member, myself. Alien animals, as we define them, are animals inhabiting a habitat where they are not native. These can be animals which have been introduced into new areas by human intervention, animals moving along pathways which have been created by human activity, or animals which have expanded their range into an unexpected area through natural process.

During this quick introductory post, I will be having a quick look at examples of alien animals in Britain, discussing our plans for the future, and finally, looking at what you, CFZ members and representatives, but first and foremost naturalists, can do to help our studies.
So first, some examples. New area introductions are numerous and well known.

The coypu is a great example. Introduced into fur farms in 1929, this large (4.5-9kg) rodent swiftly made its escape, and soon found that the habitat in East Anglia was very much to its tastes, where it settled and bred very nicely. This news was initially taken as good tidings: Coypu eat a lot of reeds and would clear streams wherever they went, keeping them free flowing. However, it was soon found that they loved vegetables from gardens, and crops from farms, plus their reed clearing activities and burrowing would only cause the river banks to be undermined and collapse. Their only predators big enough to take the babies in Britain were foxes, stoats and herons; they would leave the adults (if only we still had wolves...).

Now, you may be saying to yourself “Well, this is all well and good, but in their native habitat [throughout South America] surely they would cause a huge amount of damage to the area?”. Well, no. Coypu in Britain had hit such densities thanks to so much food from our farms that their numbers could sky rocket. Indeed, some clever ecologist worked out that only when Coypu hit a density of 4 per acre, do they begin to cause large amounts of damage. A huge number of Coypu living in one area of course results in far more burrowing structures than normal, causing bank undermining, and increasing the risk of flood damage.

So, that is new area introductions dealt with, but what about new pathway introductions? This is a bit of an odd term, and I will try to make it clearer. When animals are removed from a food chain, a gap appears which may be suitable for another animal to exploit. For example, by removing top predators like wolves and bears from Britain, we have produced a gap which will be filled by evolution (maybe not now, but certainly in the future, evolution can take a long time to work!). So, by removing these predators, there is a top spot available which is just beginning to be filled by (for the purposes of this article) two types of animal. 1. Big cats, 2. Eagle owls (amongst others)

Big cats, you are quite right, are new area introductions, but they have adapted to new pathways which we have left open. Eagle owls however, may or may not have been present in Britain in recent times before extermination, but they are back! Some birds are undoubtedly captive releases, but some of them I am sure are birds who have flown over from the continent, found a huge amount of prey (from voles to rabbits and even up to buzzards (who incidentally have moving up into that top carnivore slot)) available, so they decided to stay here.

There is currently a male Eagle owl who lives outside the Biology building at Bristol University, which does push this university a little higher up my favourite list for next year. This young fellow is almost certainly a captive release however, but it is still quite interesting! Eagle owls enjoy a bit of a love hate relationship with people, they are stunning birds which people love to see flying around, but when it turns out that they may eat the occasional game bird, the shooting lobby fires up (pun intended) to claim that they should all be shot.

I have nothing against game shooters; indeed, working on a shooting ground has shown me the great help they can be to keeping some species of British bird breeding on land which would have otherwise been eaten up by housing or farmland. The great expanse in breeding areas for game birds must be a good thing, for, as Pink Floyd said, “the price of a few hundred ordinary lives”.

So, that is the basics sorted out. Now for our aims.

We hope to set up a sighting and watch database where we log sightings of alien animals alongside notes about their environment, activity and numbers. We are looking to produce a book by the end of the year: either it will be a monster of a book looking at every alien animal in Britain, from the confirmed to the unconfirmed; or it will be a book split into three parts:

  • Mammals
  • Birds
  • Reptiles, amphibians, and fish
  • Invertebrates

but we shall have to see.

The most important factor in making this venture work is you! The people up and down the country who want to help this project go. You can do so my informing either Jon Downes or myself of any sighting you have of an alien animal, together with as much information as you can get about it (not the animal species itself, but what they are doing there, their size, estimated weight, habits, food source etc), or by suggesting ideas and suggestions to helping this get started. We hope to have you on-board soon.