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Content Updated: 12th May 2013

SEASONAL UPDATE: May 2013

Well, we’re in the final throws of spring and the weather has recently taken a decided turn towards the unsettled! After an uncharacteristically warm spring bank holiday here in the south, the temperatures have dropped from a balmy 23oC (73oF) to more like 12oC (54oF), with some strong winds and heavy rain forecast to last well into next week. Still, the couple of weeks of lovely weather we have had in late April and early May have led to something of a baby boom and a recent trip to the Wildfowl and Wetlands Trust reserve at Arundel (West Sussex, UK) saw us up to our metaphorical knees in baby ducklings, along with some baby moorhens, baby coots and, most stunning of all, two recently-hatched Lapwing chicks. Check out the Wildlife Online Gallery for pics. Before we get into the wildlife around this month and the ‘Pick of the Month’ species, there are a couple of interesting wildlife news pieces to mention. First-off, the BBC Wildlife Magazine wants people to vote for Britain’s national species; there are 10 contenders, including the swallow, water vole, oak, ladybird and hedgehog. Speaking of hedgehogs, May plays host to National Hedgehog Week, organised by the British Hedgehog Preservation Society with the aim of getting people to help hedgehogs in any way they can – there’s a lot of good advice for gardeners on how to make your garden hedgehog-friendly on their website. So, despite actually being last week (perhaps I should address the homepage updates earlier in the month?!), the message and spirit of National Hedgehog Week remains: whatever you can do to help your local hogs (e.g. stop using slug pellets, take extra care when strimming borders, leave an untidy corner of the garden, etc.) can make a big difference. Also this month BugLife are running their third annual Oil Beetle Hunt and are asking for people to record any sightings of these insects you may get while out walking in meadows, grassland and open woodland. BugLife will also be running a Pollinator Survey between July and September this year and you can register your interest and find out more on their website. Now, on with the show!

Fox cubs are now out-and-about and reports are coming thick-and-fast of people seeing cubs playing in their gardens. Most cubs will be about eight weeks old by now and most will be fully weaned, although the vixen may continue to lactate until about mid-June and the cubs often supplement the prey they’re given by their parents (often also by extended family members) with milk from mum. May is a good month for fox watching as not only are the cubs abroad in daylight, the adults are very active as they rush about trying to find enough food for themselves and their hungry litter. Badger cubs can also be seen above ground now and, although they’re slightly older (more like 10 weeks), most cubs won’t be fully weaned until the middle of next month. Hedgehogs are breeding at the moment, although I’ve not come across any reports of hoglets yet, and towards the end of the month Roe deer does will drop their kids. Indeed, with regards to baby deer: in the event that you come across a young deer curled up in the vegetation please leave it where it is and do not attempt to touch it. Deer mothers leave their young lying up in tall vegetation for a couple of weeks after birth; this is perfectly normal behaviour and, unless the deer looks to be injured, it has not been abandoned and does not require rescuing! If there was a lot of squirrel activity in your local park at the start of the year, it’s a fair bet that there will be squirrel kittens around soon; winter mating typically leads to kittens born in late-April or early-May. The mole breeding season is coming to an end now with most females having already given birth, although it will be June before any young are seen above ground. Many Brown hares will have had their first litter by now (females average three litters per year during a breeding season running from February to October).

May is a great month for bird-watching and, more specifically, for bird listening! The return of the cuckoo, the chirruping-whistle of the nightingale (below, left), the bubbling churr of the nightjar and the treacly spring song of the blackbird lift the spirit. Tawny owlets can be found branching during this month, while most other owl species will be feeding chicks during this month, making May a good month for owl-spotting. Unfortunately, strong winds and rain aren’t conducive to hunting for prey if you’re an owl. Many of our garden birds are now either in the final stages of nesting or are sitting on eggs; some Blue-tit eggs may have hatched already and I have had a couple reports of potential fledging already! Overall, however, given that most things seem late this year I’d be surprised if many garden birds had fledged yet. Towards the end of this month is a good time to look for recently hatched cygnets and Great crested grebe chicks. Most people will have noticed that swifts, martins and swallows are now back in the UK and for the last several days we’ve had swifts screaming over our house as they search for insects. Other species around during May include stonechats, skylarks, hobbys, winchats, lapwings, geese, turnstones, Spotted flycatchers, and redstarts.

Most of the amphibian breeding activity has ceased now with spawn having developed into tadpoles. May is, however, a good month for reptile spotting as we’re now into the breeding season for most species. Indeed, while out on the New Forest searching for Sand lizards on bank holiday Monday we were treated to a spectacular copulation rumble by a pair of Common lizards (see bottom of update). As the days get warmer and sunrise earlier it can be tricky to catch more than a fleeting glance of many reptiles, which need to spend less time basking before moving off to hunt. That said, early mornings can still be a good time to go in search of adders, Grass snakes and, if you’re very lucky, the rare and elusive Smooth snake. I mentioned Sand lizards and May is a good month to go in search of these spectacular reptiles; the males are at their most vibrant (sporting a bright green and brown marbled pattern) as they focus on breeding. Unfortunately, Sand lizards are confined to heathland in the south of England, which rather limits your opportunity to find these amazing little lizards.

Spring seems to have gotten off to a rather delayed start owing to the very cold weather in late February and early April and, as a result, there seem to be fewer of those typical spring butterflies and flowers around. Butterfly-wise, I have seen a couple of ‘blues’ (too distant to assess species), a couple of very active ‘whites’, some brimstones, a peacock and a couple of Speckled woods. Based on reports from friends I believe other species are around (e.g. Orange-tips, Green hairstreak, etc.), but they’re not particularly commonplace yet. There seems to be plenty of spider activity at the moment and most of the dozen Wolf spiders I saw in the garden this morning were carrying pale blue eggsacs with them. We also had a visit from a Woodlouse spider in the conservatory earlier this month, which was fantastic. Other species to keep an eye out for this month include Pearl-bordered fritillaries, Maybugs (aka Common cockchafers), Purple emperor butterflies, Soldier beetles, bees and hoverflies, and the variously decorated longhorn beetles.

I’ve only recently (i.e. in the last week) seen bluebells around, which is later than in previous years, but there are still Pink campion, primroses and violets in roadside banks and a considerable amount of blossom on the trees (despite the strong winds!). If you fancy seeking out some plants this month, why not brush up on your orchid identification: Early spider orchids, Bird’s-nest orchids, the dazzling-pink Lady orchid and the aptly-named Early purple orchid are to be found in May. While you’re out, you may also want to help survey the state of Britain’s wildflowers – PlantLife are running a Wildflower Count. If you’re heading for the coast this month, Spring squill, English scurvy grass and Common thrift (or ‘sea pink’) are among the plants on display, but if you look out to sea you might be able to spot something much larger and more spectacular: a Basking shark.

Pick of the Month for May – The Basking shark (Cetorhinus maximus)

The group of marine predators that we refer to as sharks are among the most feared animals on the planet. Say the word “shark” and most people conjure up an image from Jaws of a Great White attacking a boat or, worse, a human! The 1975 film Jaws did little to improve the public image of sharks but, contrary to popular misconception, far from being a far-fetched Sci-Fi notion it actually represented pretty much all that was known about the White shark at the time and had many heavy-weights in the world of shark research as consultants. More importantly, it inspired countless generations (of which I am part) to want to learn more about sharks and to see them as a group of biologically fascinating and ecologically essential animals. We now know that there are in excess of 450 different species of shark, the vast majority of which grow to less than two metres (6.5 ft) in length. One exception to that last statement is a giant that visits Britain’s shores during the spring and summer months: the Basking shark.   The Basking shark -- so named because early observers mistook its slow surface swimming while feeding for basking in the sunshine -- is the second largest living shark species known to science. I confess to being pedantic over the size of this animal, which is often cited simply as the “second largest fish” or “second largest shark” in the world – the world’s largest shark/fish species is the Whale shark (Rhincodon typus), recorded to reach a whopping 21m (just shy of 70ft!), so technically the second largest fish in the world is probably another Whale shark! Hence it is more accurate to refer to the Basking shark as the second largest fish species in the world! Anyway, pedanticism aside, there is no denying that Basking sharks are large animals: historic records put them anywhere up to 15m (49ft), but most of the empirical data we have suggest 10m (33ft) is likely to be closer to the maximum size and very few animals (i.e. fewer than 10%) recorded in British waters exceed 8m (26ft).

Key to how Basking sharks are able to grow so large is in the food they eat. You could be forgiven for thinking that a shark with a mouth almost 1.5m (5ft) wide and containing up to 480 hook-like teeth could eat pretty much anything it wanted. These teeth are, however, tiny and Basking sharks are planktivorous – in other words, they feed on the microscopic plants (phytoplankton) and animals (zooplankton) that drift in ocean currents. Plankton is filtered from the water by a series of cartilaginous gill rakers located inside the gill slits. The shark swims, mouth agape, at a speed of roughly two knots (about 2.5 mph or 4 kmph) – water is diverted into the mouth and out through the gills, with plankton getting trapped by mucous secreted onto the gill rakers. Periodically, the shark will close its mouth, collapsing the gill rakers and thus scraping the plankton off into the mouth; the resulting plankton-mucous ball is then swallowed. This is a very efficient feeding mechanism and the sharks are capable of filtering more than 2,000 tons of water per hour – in other words, they could filter an Olympic swimming pool every couple of hours! Moreover, plankton are an abundant food source, meaning that Basking sharks have access to vast quantities of these tiny prey and this large energy supply is part of how they can reach such considerable sizes (see Q/A: How do Whale and Basking Sharks grow so big eating such small fodder?).

So, what is it that draws Basking sharks to Britain’s coasts? Well, breeding seems to be part of the equation, and there have been reports of courtship behaviour (including nose-to-tail following, with the female in the lead) in this species off the UK between May and July. That said, very little is known about Basking shark breeding biology and, although the sharks may breed while here, it is most likely that they are initially attracted by food.

Plankton availability varies considerably with water conditions and, as a consequence, Basking sharks are highly migratory. Towards the end of spring an area of warmer water from the Atlantic ocean pushes its way into the cooler coastal waters off southern Britain; where these warm and cold water mix, an area known as the Ushant front, high nutrient levels are found and this promotes phytoplankton growth. When phytoplankton bloom, so too do the species of animal (i.e. zooplankton; largely calanoid copepods) that feed on them. When the conditions are calm, these critters form visible ‘planktonic slicks’ on the surface; it is these blooms that the Basking sharks are attracted to. Consequently, Basking sharks are generally first seen in the western English Channel and the southern Celtic sea during May. During ‘invasion’ years, shoals of several hundred animals can be seen off the coast, although numbers vary considerably from year-to-year largely in accordance with sea surface temperature rather than, as might have been assumed, zooplankton density. Shark sightings start in south-western England (prime spotting sites include the Lizard peninsula, Penzance, and Falmouth), with the sharks moving north into the Irish Sea and up to the Firth of Clyde and Sea of Hebrides as the summer progresses. We know that the sharks can track the zooplankton density across large areas, although we currently don’t know exactly how they do it – suggestions range from an inherited memory to the sharks being able to smell compounds released by the zooplankton while they’re feeding on algal blooms. However the sharks manage to find the blooms they seem to stick around until the zooplankton density drops below a critical level, which occurs towards the end of summer; by November, the sharks head out to deeper water. Indeed, until relatively recently the movements of Basking sharks over the autumn and winter was a mystery.

In 1953 Dutch zoologists Antonius van Deinse and Marcus Adriani published a paper in the journal Zoologische Mededelingen in which they described how four of seven Basking sharks stranded on beaches in The Netherlands 1950 and 1952 lacked gill rakers. This curious lack of gill rakers caused a stir in the scientific community, posing the question of how the sharks fed themselves during the winter. In a paper to the Proceedings of the Zoological Society of London during May of the following year, Hampton Parker (at the British Museum) and Marinus Boeseman (at the National Museum of Natural History in The Netherlands) suggested that the sharks moved into deep water during the autumn where they shed their gill rakers and stopped feeding while the rakers re-grew. Eight years after Parker and Boeseman’s paper, British zoologist and Scientific Director of the Zoological Society of London, Leonard Matthews developed the theory further and, based on his calculation that a 7m (23ft) Basking shark would require 663 calories simply to keep swimming for an hour that the winter plankton density could not provide. In his paper to New Scientist, Dr Matthews suggested that these sharks solve the problem of a winter plankton drop by:

“... throwing away its rakers worn by a season’s use, refraining from feeding, sinking to the bottom and hibernating. At this moment there are probably great schools of these enormous fish quietly resting on the bottom of the sea, perhaps in the heads of the canyons at the edge of the continental shelf, with their metabolism running at its lowest level while they grow their new gill rakers ready for browsing on next summer’s crop of plankton.”

The shark enthusiast in me smirks at the thought of schools of torpid Basking sharks littering the sea floor waiting for spring, but at the time the notion was entirely plausible in a biological sense. Moreover, Basking sharks had long been fished -- indeed, over-fished -- for their liver oil, which had various commercial uses, including as a lamp fuel and the livers of this species were some of the largest around. (Without swim bladders to keep them afloat, as is observed in most bony fishes, sharks and their kin have evolved large livers filled with low-density oil that helps them remain buoyant.) So, the theory was that the sharks could ‘tough out’ the winter months by living off the oil accumulated during the spring and summer; not unlike hibernating bears or hedgehogs living off the fat reserves they’d built up earlier in the year. Subsequent sightings of Basking sharks during the winter hinted that Matthews’ theory was incorrect but, quite unbelievably, it was not until almost 40 years later that the mystery was solved! Matthews’ calculations suggested that Basking sharks would lose out if plankton densities dropped below about 1.4 grams per litre – so, if there was less than this much plankton in the water, the sharks would burn more energy filtering it out than they’d recover digesting it. In a 1999 paper to the Proceeding of the Royal Society of London, however, David Sims (at the time based at the University of Aberdeen, now at Plymouth University) reassessed the calculations based on his studies of these sharks off Plymouth. Sims calculated that, in theory, an individual Basking shark can actually make a living until plankton levels drop below 0.55 grams per litre (if feeding as part of a group, levels must remain above 0.74 g per litre). Sims’ observations of Basking sharks foraging in plankton densities as low as 0.48 g per litre support his theoretical calculations. If we consider that the waters off Plymouth often support 0.62 g per litre of plankton during the winter months, it seems that the sharks would have no need to hibernate. Given that this winter density is below the ‘group threshold’, however, probably explains why only the odd one or two sharks are spotted off our coasts during the winter. So, if the sharks don’t hibernate, where do they go? Sims has provided some clarification here too, having radio-tagged several sharks off Plymouth during the summer and followed their movements over the year.

When we add Sims’ data to that of Cornish Wildlife Trust naturalist Colin Speedie who has been tagging Basking sharks off Britain for more than a decade and we’re slowly getting the picture. Some of the sharks that Sims tagged in the English Channel stayed in continental shelf waters, while others migrated offshore into deeper ‘shelf-break’ waters off the west coast of Ireland down to the Bay of Biscay. The biologists think the sharks continue feeding here, where plankton densities are higher, making surface to depth migrations following their prey.  It seems that some sharks may go even further afield; crossing the Atlantic. It had long been considered that North American and European populations of Basking sharks were isolated (indeed, a paper in 1976 suggested there were actually four species that were geographically distinct) but more recently we have found data to suggest otherwise. In a fascinating brief paper to Biology Letters, a team led by Marine Conservation International biologist Mauvis George report on the travels of an 8m female shark tagged off the Isle of Man in June 2007. The shark moved south through the Irish Sea and, at the start of July, left the tip of Cornwall heading out into the Atlantic; when the tag detached, 82 days after it was attached, the shark had arrived in the waters off Newfoundland in Canada, a straight-line distance of almost 9,600km (just under 6,500 miles) and, during the journey, she was recorded to dive to just under 1,300m (almost a mile), the deepest dive record currently held for this species.

Despite these glimpses into the world of the second largest shark species, we still have so much to learn. So, if you find yourself on the western coasts of the UK this spring and summer, keep an eye out for Basking sharks and please report any sightings via The Shark Trust’s website, which also contains details of the Basking shark Code of Conduct, for anyone planning on swimming with a Basking shark or approaching them in a boat. The code is aimed at minimising disturbance to the animals and making the experience enjoyable for all concerned.

Whatever you get up to this month, have fun and I look forward to seeing you back here next month. I'll leave you with a photo of the fascinating courtship of the Common lizard (Zootoca vivipara); the male is sporting the bright orange belly and is firmly gripping the female's hind quarters, not unlike a scaled down crocodile on a carcass in the Zambezi River!

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Okay, for those of you that are new to the site, let's take it from the top!

What is Wildlife Online?
Essentially, WLOL is an educational website about British wildlife. The site contains profiles of various British animal species, with new articles in preparation all the time. The site also has articles looking at wildlife-related subjects, including hunting and animal emotions. This site is purely a hobby of mine; it does not generate any money or contain any advertising and, for the time being at least, I am happy for it to stay that way.

What does Wildlife Online aim to achieve?
The ultimate goal of the website is to be useful. My intention has always been to provide un-biased, accurate information that’s accessible to anyone with an Internet connection. Increasingly people are coming into contact with their local wildlife and whether such interactions are positive or negative, they generally inspire a desire to learn more about the species. Moreover, there are still a great many misconceptions surrounding our wildlife (fox behaviour springs immediately to mind) and these are brought up time and time again during discussions in the media. Each article aims to provide a reasonably comprehensive overview of the species in question by drawing on information from the media, books, TV programmes and the scientific literature. I feel that this combination of sources, along with my own observations and those of my friends/colleagues/readers provides a unique online resource of British wildlife information. My hope is that the information provided here will go some way to changing people's perceptions of the creatures with which they share their parks and gardens.

Why create a website when there are books and TV programmes about your subjects?
Books can be a fantastic resource and I can't imagine being without my library. Not all libraries, however, are equally well stocked, and not everyone has the funds to splash out on what are often very expensive wildlife books (especially those written by scientists). More importantly, much of the scientific research never makes it out of the journals into books and TV shows. Similarly, many of the early books -- which contain some of the pioneering work on the species -- are now long out of print and can be difficult or expensive to track down. Books have the 'luxury' of being able to devote their entire contents to a particular species, covering all aspects of its life history. Television, by contrast, is a much more limited and variable medium: the programme editor(s) has to create a show that is likely to hold the viewers' attention and appeal to a very wide audience. The result is that, although some reach this compromise very well (the BBC, for example), many documentaries focus heavily on the 'wow factor' (multitudinous slow motion shots of Great whites leaping out of the water in pursuit of seals, for example) and this often comes at the inevitable expense of the information about the animal. Finally, both books and TV programmes go out of date quite quickly; new research is being conducted all the time. Consequently, a website is an ideal and dynamic intermediate - it offers the opportunity to provide a decent amount of information about the subject that can be updated at the metaphorical drop-of-a-hat as any new research is published.

Why include so much information?
I honestly believe that if a job is worth doing, it's worth doing well. There are hundreds of websites with brief species profiles and if that's all WLOL offered there would be little point to it. I understand and appreciate that some people find being confronted with large volumes of text very daunting while others are of the 'too long; didn't read' mind-set and will thus be turned off by the amount of text facing them. I have tried to remedy this as far as possible via two avenues: there is a Speed Read section with a brief profile of each species featured in a main article; and each article has been 'virtually split', with the aid of hyperlinks, into sections that allow people to easily jump to the information they're looking for. Ultimately, I want to provide as much information as is feasible in order to provide the reader with the clearest appraisal of each species or topic; I hope that most readers approve of this approach.

Why haven't you included a complete bibliography?
My intention with WLOL is to provide the information in an accessible format, which means that anyone should be able to read an article and understand the information in it. Consequently, I didn't want to format it as a scientific paper because the current format allows for a much more informal approach and writing style which, I hope, will appeal to a wider audience. Most people should find enough information in the article (I typically provide the name or one or more of the authors and the journal and year) to track down the original scientific paper. When I take information from books, I always give the name of the author(s) and the full title of the book for easy reference. I am also happy to provide full details of any of the references upon request.

Are you really qualified to do this?
I'm certainly not an expert on any of the subjects presented on this site. The articles stem from my varied interests in natural history and biological sciences. In terms of qualifications, I trained as a scientist (studying natural sciences at degree and postgraduate level) and all I really do is interpret information, blend it with associated research and personal observation, and present it in what I hope is an accessible format. Unless specifically stated, I do not claim any of the information on this site to be my own research. I have built relationships with some of the many diligent researchers who have produced the data that I use, and I am happy either to recommend an expert or provide my own opinions on a subject.

As a final note, I want to make a quick reference to the quality of the material on the site. The great French philosopher and mathematician, Rene Descartes, once said: "If you would be a real seeker of truth, you first must be willing to doubt as far as possible all things." This is very sage advice, especially when it comes to believing what you read on the Internet. Most Internet sites (indeed, some books and TV shows too), including this one, have no form of peer-review (i.e. nobody with experience of the topic checks the site for accuracy); consequently pretty much anyone can have their own little corner of cyberspace and information can make it onto websites that is either misguided, or downright false! When creating material for this site I take every care to ensure that the information I present is accurate. Invariably errors will creep in; typos are almost inevitable (although each article goes through several levels of proof reading before it appears online) and research is always underway on the species featured here, so the data can go out of date almost overnight. Each page has regular (ish!) reviews, however, during which I update the information, adding details of new findings and taking out that which is now thought highly unlikely. You can see most of the books I have used in the preparation of this site on the Recommended Reading page and I have provided links to some of the most interesting sites I came across during my research – these can be found under the appropriate sub-heading on the Links page.

Anyway, I digress.... I hope you enjoy looking around the site and I hope equally that you get something worthwhile out of it. Any comments, suggestions or (constructive) criticisms are welcome via e-mail - appropriate addresses can be found on the Contact page.

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DISCLAIMER: All the photographs and artwork on this site are either my own work or have been donated by readers. All images remain property of their authors and, if you wish to reproduce any of the pictures, consent must be granted by the appropriate person - requests can be directed via myself or see FAQ. For more details on the content of this site, please see the full WLOL Disclaimer.

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