Nature Blog Network

Friday, 28 August 2009

The white hot flame.

White morphs of aquarium fish are relatively easy to find in aquaria. Albino Giant Danios, Convict cichlids, Tiger Barbs, Oscars, Kribensis, Guppies and Mollys are commonly found in pet shops, as are leucistic morphs of Bristlenose and Sailfin plecs. Leucistic morphs occur when there is a lack of melanin pigment (the pigment that causes dark colours in organisms) over the body, but not on the eyes. You may have read Jon’s blog this morning whereby he mentions some white Firemouth cichlids. These are common aquarium fish, mainly bought for their attractive red throats and ease of care and breeding. The photo below shows a male engaged in a visual threat display.

I will now take the time to completely move off topic and talk about visual threat displays in cichlids. Firemouths and their genus (Thorichthys) are one of the few cichlids that have evolved a mechanism to reduce the amount of energy expended when defending their territory. Cichlids as a group are extremely territorial, and males usually go for the full blown method of defence; attack. As a way of defending your livelihood, it is a good technique. It is fast, as the biggest male usually wins, but often wounds are sustained which need healing. This healing, together with the actual act of fighting, incurs a cost to the fish, that of using energy from food to provide energy to perform these two acts. This energy would have been spent normally on getting big, and thus the fish is able to win more fights. Cichlids don’t have great eye sight, and as they usually live at the bottom of rivers and lakes, visuals are not normally that important, so they are usually dull in colour, or coloured in very obvious patterns (the convict is a good example, being banded completely in black and white). Firemouths have however evolved a method of defence which reduces the energy lost by fighting. The red throat from which they get their common name can be expanded to produce a very obvious signal. Indeed, in a study by Evans and Norris (1996), males with larger and redder throats won more display conflicts than those that did not, regardless of size! So, a very large, but dull male would lose to a colourful, but much smaller male. Only if the opponents are matched in colour will they actually fight. Interestingly, and again, in opposition to most cichlids, female Thorichthys are almost as colourful as males, but smaller. In normal cichlid pairs, the male defends the territory, leaving the female to tend the eggs and fry, but with these guys, both sexes help defend. This makes the territory more secure, and ensures better survival for the fry.

But how have they evolved this method of display? With a cichlids standard eye sight and choice of habitat this display would not really be seen! It would seem then that Thorichthys have evolved better eyesight than normal cichlids, but also live in clearer waters where they can see each other properly. But to my knowledge this experiment has never been carried out! Never mind. Interestingly, you may have seen Jon or I blogging about out Thorichthys sp. “Mixteco Blue”, an undiscribed species. These guys don’t have the same throats as Firemouths, but it will be interesting to see if they have the same displays. Anyway, to the crux of this blog.

Jon spoke about white Firemouths the other day (photo above), presumably these are either albinos, or leucistic. Either way, these guys don’t have the red throats that are as we have seen an integral part of their lifestyle. So, will this change their display? I would expect that it does. If we can get hold of some of these guys and raise them to adulthood, we will be able to perform experiments on them to see if the display is actually present or if they omit it completely and resort straight away to violence. If they do try to display, what will the outcome be? As the red is reduced drastically, with they just give up and fight? But my main point is that if these fish do display to each other, fail to resolve the struggle visually and end up fighting, is it right to breed fish which are unable to perform their natural behaviour? Personally, I don’t think it is. We will certainly be having a go at breeding them, but not to sell on the offspring, but just to see if there is any change in behaviour, but I am sure most who keep them will not be so scrupulous. I would love to know if it is just me who thinks this, or if I have any more support out there!

Thursday, 30 July 2009

BITTERN BOOGIE DROPOUT




Max has just finished his A-levels, which is - I suppose - a perfectly valid reason for him not having done any bloggo stuff for yonks. However he has managed to sneak out a few times to sit in his car and listen to Tarkus with a peculiar look on his face, and occasionall to do a little bit of bird watching. He usually takes his camera with him, and over the last few months has built up a fantastic library of images of the wildlife of the Wells region of Somerset. Here are some of them...


Bitterns are very strange birds. Being a heron they have the families typical features of a long bill, long legs and a fondness for fishing. My two local nature reserves, Shapwick Heath and Ham Wall, have been given large grants in order to attract bitterns. They need extensive reed beds, but with water levels such that they can build a nest which is at ground level, but not in danger of any flooding. The two nature reserves are at such an altitude that they are not in risk of flooding from global warming, even if the estimate of 17ft higher sea levels (the last interglacial period had sea levels 22ft higher than today, so this figure is not really, in a long term view, anything to worry about) is found to be too small, then the bitterns will be fine as they are well above sea level. This makes the colony sustainable in the long term.

Anyway, bitterns are now breeding at Ham Wall, which is great news. I went down there a few weeks ago to see what I could see, and I saw 7 episodes of flight from the bitterns, plus 3 lots of booming from the males. The photos from this trip are shown below. At Shapwick Heath I have seen 3 bittern flights, but they are not currently known to be breeding.

As an interesting postscript, there is a Little Bittern at Ham Wall at the moment. This is a rare bird indeed, not currently breeding in Britain. They are found all over Europe, apart from Britain. It would not surprise me if within 20 years they begin to breed in Britain. At the bottom of this page is some footage of it being bitterny.






Tuesday, 7 July 2009

HEY HEY MAMA SAID THE WAY YOU MOVE, GONNA MAKE YOU SWEAT GONNA MAKE YOU GROOVE

Hopefully most of you will have read the initial Gurt Dog story from yesterday, plus Dan Holdsworth’s posting this morning. To answer his question, posted as a comment on the original story, in a public way, the sighting occurred somewhere to the North East of Westbury Sub-Mendip along one of the country lanes. Looking on Google Earth, you can find the rough area by searching the above village and moving up the hill to the North East, moving to an eye altitude of 12000ft, with Priddy toward the top right of the image, Westbury down the left hand side about halfway up, and Ebbor Gorge and Wookey Hole Caves in the bottom right of the image. From this position, you can pan to the East until you reach a village called Rookham. This village marks the easterly border of the sighting area. This should give you a good view of the area, mostly of fields and a small wooded gorge. The sighting would thus have been at quite a high elevation, between 700-900ft above sea level. A rough set of coordinates is: 51º14’10 to 51º15’00 North, and 2º42’17 to 2º39’00 West.

For those without Google Earth, Google Maps will work fine. In fact, it is probably best to look at both Earth and Maps to get a good feel for the area, only Maps shows the roads along which the sighting must have occurred. Just follow the above directions with this URL: http://maps.google.co.uk/maps?daddr=Westbury+Sub+Mendip,+Wells,+Somerset,+UK&geocode=CUqSmQK1JgThFVreDQMdz4vW_w&dirflg=&saddr=wells&f=d&hl=en&sll=51.246283,-2.716713&sspn=0.022458,0.055017&ie=UTF8&ll=51.23043,-2.669334&spn=0.044932,0.110035&z=13

The village of Priddy has always had an association with big cat stories and sightings, most of which are in the roads toward the South East of the village. They pop up from time to time in the local paper, along with the occasional livestock kill. Now, I am sure that some big cat sightings are spectral in origin, but the vast majority are of flesh and blood animals in the way we understand it. Other than the generalised Black/Gurt/spectral Dog stories, I was unaware of any sightings of the fellow around the North of Wells, until now of course.

Looking at the website that Dan Holdsworth posted up earlier, if you match up the images of North Somerset, then click on “view layers”, and tick the box on Europe marked “Europe BRGM 1:1.5M Faults”, you will see a series of black lines, along which faults lie. If you match the One Geology map up with either Google Earth or Maps, it can be seen that Westbury Sub-Mendip lies very very close to the most northern fault in Somerset. However, if you match up the coordinates on the One Geology with those obtained from Google Earth, the village ends up being much further inland than it actually is. If the position of the fault is correct, then the village of Westbury Sub-Mendip lies close enough to the fault for this sighting to provide evidence for Dan’s theory about faults and zooforms being linked, but I cannot find if the fault is still active. I have found a list of earthquakes in Somerset, but this is unfortunately only dates, not locations.

However, my computer decided to restart, and for the life of me I cannot find the webpage again! So, instead we have some details of earthquakes that have occurred in the Wells area. Mathew of Paris recorded the effects of the Wells' earthquake on December 21, 1248:

“...an earthquake occurred in England, by which (as told to the writer of this work by the Bishop of Bath in whose diocese it occurred) the walls of the buildings were burst asunder, the stones were torn from their places, and gaps appeared in the ruined walls. The vaulted roof which has been placed on the top of the church of Wells by the great efforts of the builder, a mass of great size and weight, was hurled so as to strike great terror into all who heard it....”

The Somerset and Dorset Notes and Queries for 1895 gives details about a number of shocks around Priddy, Wells, Shepton Mallet and Glastonbury on December 30, 1893. At Wookey it seemed as if the earth was assuming an undulating motion, such as is observed on the waves of the sea. The first of the shocks, for there were several, was preceded by what seemed to be 'a terrific explosion' (Anon, 1895). This explosion is the noise that the fault made as it slipped, thus showing that the fault was close by.

Ahah! My efforts have been rewarded! Anyone seriously interested in researching zooforms and faults will enjoy this groovy tool. Follow the link below and hover over the “Earthquakes” tab at the top. Move the mouse down to “Interactive UK Earthquakes Map”. In the new window you can select the area you want to look at, then fiddle around with the tabs on the left hand side. Zooming in on the sighting area there are 5 earthquakes occurring within 10kms of the rough sighting area. One occurred 8kms away, one 4kms, one 7kms and 2 10kms away. Evidence? I should say so!

Thursday, 18 June 2009

A ROE BY ANY OTHER NAME




Max is in the middle of his A-Levels at the moment, which is - I suppose - a perfectly valid reason for him not having done any bloggo stuff for yonks.

However he has managed to sneak out a few times to sit in his car and listen to Tarkus with a peculiar look on his face, and occasionally to do a little bit of bird watching.

He usually takes his camera with him, and over the last few months has built up a fantastic library of images of the wildlife of the Wells region of Somerset. Here, in a new series, are some of them...










I was out bird watching ‘t other day to stop myself from having a mental breakdown, (it being the second week of my A-Levels) and I found myself sat in a silent hide hoping for something interesting like a hobby or bittern to pop down, drink a pint of shandy (you can’t drink and fly remember) with me in front of the camera, before going off about on their daily business. I waited for half an hour or so, and heard a rustling in the reeds to my left.

“Great Scott!” Exclaimed I, “It must be a hoatzin!” (OK I didn't say anything of the sort, but in my Biology exam yesterday there was a question about hoatzins, and I feel incredibly smug because I think that I was the only person in class to know what the hell they were).

It was not a hoatzin, but a very cute female roe deer with her young (interesting rod deer fact: their coats are grey in winter (see the photo posted on my blog a while ago about the roe deer being killed by a big cat) and a light orange to red colour in the summer).

They were not bothered by me, and came to within 10 yards of my position, not minding as the camera shutter clicked or I dropped my binoculars. The female moved into the reeds in front of me, whilst the baby stayed a little way back, obviously still a bit new to this whole thing.

Sunday, 14 June 2009

Grebe-oh Guru




Max is in the middle of his A-Levels at the moment, which is - I suppose - a perfectly valid reason for him not having done any bloggo stuff for yonks. However he has managed to sneak out a few times to sit in his car and listen to Tarkus with a peculiar look on his face, and occasionall to do a little bit of bird watching. He usually takes his camera with him, and over the last few months has built up a fantastic library of images of the wildlife of the Wells region of Somerset. Here, in a new series, are some of them...




Whilst out at a local reservoir checking out the local birds, I saw a pair of Great Crested Grebes. These are the largest British grebes (adults are usually 1200g in weight), though not the largest in the world , they are still impressive birds. Fire-red head tufts, often extended upon meeting another grebe, are their most impressive feature (other than their stupendous diving abilities) and form an integral part of their mating display. The male and female erect the tufts and begin to dance around each other, each doing the same as the other. So, if the male moves his head to the left, so does the female. If the female moves her head back to the right, so does the male. Note: this is NOT a mirror image!


The grebes swam closer to my vantage position, and, causing annoyance to a nearby fisherman, began to display. This was great for me, and I started snapping away. Behind me, an elderly couple walked past and the gentleman (as indeed, he was) exclaimed

“How brilliant! Crested grebes displaying. Go on son, get in there!”

The last part was yelled directly at the male grebe, who then zipped under water. Bugger, thought I , that is the end of them displaying at such close range.

The male popped back up again just as I began to wander off, with a large piece of weed in his beak. He began to display to an impressed female, and again the gentleman got overly excited and shouted “That’s the stuff lad! You are going to get some tonight!” His wife told him sharply to shut up before chatting to me about the camera.

Only when I got home did I realise that the photos were so out of focus (I have now learnt from this mistake, and have changed the autofocus point), so I must apologise for it!

Tuesday, 9 June 2009

OUT AND ABOUT WITH MAX: Egrets


Max is in the middle of his A-Levels at the moment, which is - I suppose - a perfectly valid reason for him not having done any bloggo stuff for yonks. However he has managed to sneak out a few times to sit in his car and listen to Tarkus with a peculiar look on his face, and occasionall to do a little bit of bird watching. He usually takes his camera with him, and over the last few months has built up a fantastic library of images of the wildlife of the Wells region of Somerset. Here, in a new series, are some of them...

Here, at a place called Shapwick, back in March, we see two rare egrets.

For those of you not in the know, egrets are any of several heron species, most of which are white or buff, and several of which develop fine plumes (usually milky white) during the breeding season.

Many egrets are members of the genera Egretta or Ardea which contain other species named as herons rather than egrets. The distinction between a heron and an egret is rather vague, and depends more on appearance than biology. The word "egret" comes from the French word "aigrette", referring to the long filamentous feathers that seem to cascade down an egret's back during the breeding season.

They were hunted to extinction in Britain during the 19th Century, mainly because the aforementioned feathers were so sought after.

However, they have been very succesful in recolonising the UK with four species existing here now..

However, it is unusual to see two species together at once, and Max was very pleased to be able to photograph a little egret Egretta garzetta (left) and a great egret Ardea alba (right) together.













Thursday, 23 April 2009

A non-cryptozoological trip to Redditch

You should all have by now read Ross’ turn of events regarding last Sunday’s auction. Now, I am not going to attempt to pretend that this was a purely cryptozoological trip, far from it; it was a chance for those who went to get their hands on some great new fish. Ross wanted to get his tanks started with something attractive, but easy to keep; Jon wanted anything with a sp. “something” at the end of its name; Emma wanted some fish for her community tanks; and I wanted both anything with sp. “something” (this means that this certain fish has not been scientifically described, but it is probably from the genus before the “sp.” part. So, Cryptoheros sp. "Honduran red point" relates to an undiscribed cichlid from the Cryptoheros genus, probably from Honduras) and something to sit with a couple of other medium sized cichlids in a 3ft tank opposite my chair to entertain me.

After paying the rather high entry fee, we were given a load of free tubs of food, which we worked out as being worth about £5 more than the entry ticket, so I wasn’t too disappointed. After a quick general meeting (which none of our party had much to say, we were not members), we listened to a talk by Bernd Degen, a Discus breeder and show master for over 30 years. He talked about first showing Discus (with some great photos of the massive Japanese shows) and some of the techniques people use to get that “perfect” discus, then he moved on to a talk about keeping discus in a planted aquarium, something I have always advocated.

After a break, the auction began. The first lot was exactly what I wanted, a 4” male Nandopsis salvini, a medium sized predatory cichlid from Guatemala. This is a stunning fish not that often seen in the shops. When it is, it is usual £5+ for a juvenile about 1-2” long. My male over 8 times that size for £8 was a bargain.

From then on in, our table ended up buying about12-15 lots of fish; I cannot even remember what we got! Emma got hold of her community angelfish and an unusual species of Corydoras catfish, Jon got his beloved Rams (at about half the cost of buying from a shop, and better quality) as well as Aequidens sp. “Peru” (a nice smallish cichlid, similar to the hobby staple the Blue Acara, see top photo); whilst Ross ended up with another undiscribed species (Krobia sp. “red cheek” if you are interested) and various other fish to fill his tanks up with. I got myself a group of Thorichthys sp. 'Mixteco Blue' (see bottom photo) which are currently sat in Jon’s local the Farmer’s Arms. These cost me about £3 for 8 youngsters. This is just plain stupid!

Following from the excitement of the auction, we had Alf Stalsberg, a writer and traveller who was speaking about Aequidens sp. “Silver Saum”. Time for taxonomic cock up! Aquarists may well have heard of a fish called a “Green Terror” (why? Because they are generally a metallic green, and are seriously aggressive). Now, this was thought to be a species called Aequidens rivulatus. This was debunked a good few years back, and the hobby’s fish is now known as A. sp. “Gold Saum” because of the gold edges to the fins. A. sp. “Silver Saum” is very similar, but has silver edges to the fins. Stalsberg went out to collect these fish, and found that these three cichlids represented different species. Now, the Americans (his words not mine!) “walked in and think they know everything!” and said that this was rubbish, A. rivulatus was the species in the hobby, and the others were just geographical variants. Well, says Stalsberg, do variants of a species occurring in the same river system breed only with fish with their own colour edging? No says he, they would all breed together. The fact they he has witnessed a separate breeding divide in the wild proves that they are different species. I for one feel that this argument will carry on for a long time...

After a quick raffle, we went home again to get the fish into their new aquaria. The traffic was terrible and I for one got back about an hour later than expected, but hey, if this is the price to pay for such a superb day, then I would gladly do it again.