The Return of the Red Kite

William Shakespeare once described London as a ‘city of red kites and crows’ demonstrating that this stunning bird of prey was once a common sight in our capital. Over the centuries however, the red kites fortune has varied, at one point numbering as few as 10 pairs in a remote area of Wales. Yet more recently, it has become one of the most prominent success stories in British conservation. Indeed, in many parts of the UK, the red kite is thriving.

The red kite Milvus milvus is a member of the Accipitridae family (hawks and eagles). With a wing span of nearly 2 meters, they are often seen soaring on thermals to gain altitude. Now the red kite is a scavenger, and it uses these impressive wings to stay in the air for long periods of time with minimal effort, enabling it to look for potential food. Its small body size of just 2-3lbs and comparatively weak beak and feet mean that the kite lacks the power and strength often seen in other bird of prey species, but again these are adaptations to its scavenging lifestyle. The kites are opportunistic, preferring to feed on carrion such as road kill but they will take small mammals and invertebrates given the chance. To be able to feed on larger carrion such as sheep, the kites are reliant on other species such as foxes. These open up the carcass for them, as they are lack the power to do it themselves. They are often seen in urban areas, and have become popular birds to feed in many towns. Being unfussy, they have even been known to steal food from unattended BBQ’s! Kites it seems, are one of a few species able to actively exploit a relationship with people.

By Ken Billington (Own work) [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)%5D, via Wikimedia Commons

Indeed it was this scavenging lifestyle that made the red kite highly appreciated in the middle ages, where its role for helping to keep the streets clean of waste was noted. It was so highly regarded for its efforts that the bird was even protected via royal decree, with capital punishment for any fool silly enough to kill one. The kites fortunes changed however when Henry VIII came on the scene, who seemingly not content with killing off several of his wives, also introduced the ‘Tudor vermin act’ in 1532. Now, instead of being protected, people were encouraged to target a number of ‘pest’ species, being rewarded with a bounty for each animal killed by their local parishes, and unfortunately the red kite was on this hit list. This act was subsequently renewed by Henry’s successors, and the intense persecution suffered by the kites resulted in their numbers plummeting. For each bird killed, the pricely sum of 2d was paid (with an adjusted income value, that’s equivalent to about £200 in today’s money).

As if the kites didn’t have enough problems to contend with, as they became rarer the value for their eggs and for the adults themselves for taxidermists also increased. The result? The last red kites were known to breed in London in 1777 and by the late 1800’s, red kites were extinct in both England and Scotland. The tide had well and truly turned for the red kite.

Yet despite this onslaught, the red kite managed to cling on via a small isolated population in Wales. By the 1930’s this was believed to consist of less than 10 breeding pairs, a tiny population that resulted in a substantial genetic bottleneck. When investigated in 1987, it was revealed that 85% of individuals from the welsh population were all descended from just one breeding female. But these kites had their own group of saviours, the ‘Kite committee’ a group of farmers and landowners who came together to help preserve this last remaining group of individuals. With additional incentives from the RSPB (who paid farmers for each successful nest) this population grew – albeit slowly – and reached 100 pairs in 1993.

Despite this success, the recovery of the red kite population across the UK was hampered by a couple of key issues. Firstly, red kites are highly philopatric, meaning that generally they prefer to stay in the areas close to their breeding grounds. Being sociable, while the odd juvenile will wander off, the majority prefer to remain in areas already colonised by other red kites. When the aim is to encourage a the expansion of a population, this is a major limiting factor. In addition, while the red kites have survived in Wales, this isn’t optimal red kite habitat. Due to the area being very remote, carrion can often either be more limited or harder to find due to the terrain. This means that survival rates for offspring are lower compared to more favourable habitat.

It became obvious that without a kick start the red kite wasn’t going anywhere fast. In the late 1980’s, and after much planning, the RSPB together with the Nature Conservancy Council (now Natural England) began the reintroduction of red kites in two sites in the UK. One in the Chilterns in Bedfordshire, and the other in Northern Scotland. In total, 93 birds were released at each site primarily from Spanish and Swedish populations. By 1992, both populations had successfully bred in the wild for the first time.

Since then, the red kite has gone from strength to strength. Controlled release plans in several other areas has seen the red kite reach a thriving population of 1,600 breeding pairs today – a superb increase. However sadly the red kite still faces struggles. The Black Isle population of red kites (in Northern Scotland) is struggling to increase and the cause is illegal poisoning by people. It is believed they are targeted by gamekeepers (together with other species of bird of prey) who work on grouse shooting estates. Once again, human persecution is an issue. This population was expected to reach 100 breeding pairs by 2007, yet in 2012 it had only reached 52 – far below its target.

But is the red kite now too successful? Kites have made the news on several occasions, with birds being known to steal from peoples gardens – and even being reported to the police!. Resent research in Reading discovered that up to 300 birds ‘commute’ into the town each day to be fed by food left out deliberately in peoples gardens. The feeding of kites is controversial, and many conservation groups have asked people to stop as there is enough wild food for them. Either way, it would be a shame if the success of the red kites results in them once again being labelled as a pest.

For me personally, nothing beats seeing a bird of prey and the red kite is up there with the best of them. It’s been popular, it’s been persecuted and its now one of the few species that is really bouncing back – this could be one that makes it. Compared to the often desperate struggle that most species face, it’s fantastic to see one doing so well.

How to spot a red kite:

The best time is on a lovely sunny day, when kites are often seen using thermals to gain altitude – using the columns of hot air for a free ‘lift’. While they can be confused with buzzards, the main thing to look at on the kite is the tail. It is distinctively forked, whereas the buzzard has a rounded tail. Buzzards are also more compact, with broader wings, whereas the kite has longer wings which are slightly angled. From a distance it may look predominantly rufous coloured, yet the wings are tipped black and have white patches underneath. If you’re lucky enough to see one up close you can appreciate just how colourful they are.

(Main picture By Jason Thompson (Flickr: Red Kite (Not captive)) [CC BY 2.0 (http://creativecommons.org/licenses/by/2.0)%5D, via Wikimedia Commons)

The dastardly cuckoo: The ultimate in lazy parenting

They are elusive, seemingly ruthless, cunning birds who are seriously lacking parenting skills. Preferring to let others do the hard work and raise their offspring, why is the common cuckoo so successful with its unorthodox approach?

The cuckoos familiar call can be heard from the end of April, when these dove grey birds have migrated back to the UK from their overwintering grounds in Central Africa. Found all over Britain, the RSPB estimates that there are 16,000 breeding pairs here each summer. However the term ‘breeding’ can be a rather misleading term.

Cuckoos are well known for being brood parasitic, preferring to lay their eggs in the nests of host species who will then do the hard work of raising their young. They are the only brood parasite birds in the UK, and target species include reed warbler, meadow pipit, pied flycatcher and dunnock who can end up rearing a single chick that can grow to 8 times the size of the host parent. But how do they get away with it? Cuckoos it turns out, have some rather extraordinary adaptations to assist them.

Stage one for the cuckoos is to target a nest of their host species. Within cuckoos there are certain races (or ‘gentes’) which target specific species. This allows them to lay eggs that mimic the hosts, for instance a gente targeting meadow pipits will lay brown spotted eggs. Now while this is a remarkable trait in itself, it appears to only be transferred genetically via female lineages, that is, male cuckoos can breed with any females of any gente (therefore keeping the birds as just one species and preventing a divide across birds) whereas females will produce female offspring that target specific host species so that they produce the correct eggs. This is nifty little step one.

Stage two, getting the egg in the nest. Birds it seems, can count. Foreign eggs are hastily removed if the female host believes she hasn’t laid them, and hosts that have been parasitized in the past will mob cuckoos and eject eggs if adult birds are seen near the nest. Not only will she need to lay her own egg, but also remove one of the hosts to keep the same number (which she will often eat). So the female cuckoo has to adopt another tactic, stealth. With the patience to rival any twitcher she sits and waits for her perfect moment, and can be on and off the host nest in 10 seconds. That’s quick enough to rival Usain Bolt’s 100 meters. After this, her parenting duties are over and most adult cuckoos are heading back to Africa by the end of June.

By Dûrzan cîrano (Own work) [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0) or GFDL (http://www.gnu.org/copyleft/fdl.html)%5D, via Wikimedia Commons

Next up, the chick has to ensure its survival. While its mother is now long gone, her parting gift before she left was to give her offspring a remarkable head start to hatching. Cuckoos are able to retain their eggs in the oviduct and incubate them for 24 hours before laying. Internally the temperature is 40 degrees C, compared to 36 degrees C on the nest. This allows them to hatch 31 hours before eggs laid on the same date. Not only are they bigger than their nest mates, but they often hatch before the other eggs. Born bald, blind and entirely dependent on the host parents for food (they are ‘altricial’ chicks) their next move is to eject the remaining eggs and any chicks. By placing them on their back and hoisting them over the edge, the chick removes the competition and maximises its own chance of survival.

Despite their ability to recognise foreign eggs (well, to a point), host birds seem unable to grasp the fact that this exceptionally large chick is an imposter. They have even been observed watching the cuckoo chick ejecting its own eggs and chicks and doing nothing. The reason why they cannot discriminate between chicks remains unclear. For the chick however its priorities now are food, and lots of it.

The cuckoo chick is canny, and maximises food in two ways. Firstly it calls, a lot. By increasing its begging, it can solicit its hosts into delivering the same amount of food that 4 reed warblers would normally receive between them. Unlike egg colour and shape, which is genetically determined, research has shown that the ability to call like its host species is actually a learned behaviour. They adjust their calls depending on what gets them more food, as cross fostering experiments have shown that reed warbler-cuckoo chicks transferred to dunnock nests have changed their calls to those more typical of the dunnock-cuckoos to stimulate host feeding. This blind, bald chick is able to determine what it needs to sound like to ensure its food supply. Incredible!

Finally, after it has been successful cared for by its host parents, the young cuckoo is fully independent. Remaining in the UK till around August time it then sets off on its migration to over winter in Africa, eventually reaching the same area as its parents – who it has never met!

Wildcats? Maybe not for much longer…

Controversial plans have today been announced highlighting that the wildcat is suffering not from habitat fragmentation, but conservation fragmentation too.

Scottish Natural Heritage and the Royal Zoological Society of Scotland are among 30 organisations supporting the proposal to capture wildcats to place them in captive breeding programmes. Due to be part of the Scottish Wildcat Conservation Action Plan, it aims to replicate the success of black footed ferrets (recovered from just 18 individuals in 1987) and the Californian condor (recovered from 22, again in 1987) where both species had all remaining individuals taken into captivity as a last ditch attempt to save them.

Objecting to this idea however are Wildcat Haven, who advocate keeping the cats in their natural habitat to breed. They argue that suitable threat free zones can be established around remaining populations.

While arguments can be made for both cases, what is most unfortunate is the inability for both SNH and Wildcat Haven to agree what a wildcat is. With the Scottish Natural Heritage aiming to ‘ …protect a distinct group of cats that look like wildcats, but may not all be genetically pure wildcats’, lets just hope this doesn’t end up with the Cats Protection League getting a few new arrivals.

Further reading:

http://www.bbc.co.uk/news/uk-scotland-highlands-islands-32162029

Click to access wildcatconservationactionplan.pdf

http://www.wildlifearticles.co.uk/kitty-kitty/

The badger cull: An effective solution to control TB?

Then badger, Meles meles, is a native species that the majority of the British public are familiar with. It is a charismatic creature,  with distinctive black and white colouration, and was made famous by the Wind in the Willows character. Yet this is also a species in trouble and sadly, as so often seems to be the case these days, this trouble comes from man.

Since the 1970’s badgers have been implicated in the spread of bovine TB (or bTB) as they are able to act as wildlife reservoirs for the disease. Now Bovine tuberculosis is a serious disease that despite nearly being eradicated from the UK’s cattle population, has been steadily increasing over the last few decades. It is caused by the gram positive bacteria Mycobacterium bovis., and with cattle farming concentrated in the rich pasture land of the South West, this is the main ‘hot spot’ for the disease. As it has zoonotic potential (i.e. it could evolve to be transmittable to humans), it poses a risk to human health which is why disease control is so important.

Badger culling has been advocated as a control method, yet this is an emotive issue that has caused widespread debate. The current government has announced that should they stay in power, a new cull will be implemented in July of this year and will also target cubs, despite mixed results from previous trials. But is the cull an effective long term strategy?

First things first. Badgers can have TB. They can transmit TB both between themselves and to cattle. In badgers, the disease is primarily believed to be transmitted via aerosol transmission due to the majority of lesions in diseased badgers being located in the lungs and lymph nodes with kidney lesions being the third most common. Once these lesions start shedding ‘bacilli’ (the disease causing bacterium), then the badger is infectious and able to spread the disease.

So how are they spreading the disease to cattle? The most likely way is via their urine, which they often deposit at ‘latrines’. These are often found along fence lines on pasture, and with cattle often kept out at grass during the summer, this form of indirect contact could happen particularly is the grazing becomes scarce ( often seen at high stocking densities).  However badgers do not always visit latrines present on grazing land, as they will try and avoid cattle if they have a choice. Younger badgers (less than 1 year) are more likely to visit, which is interesting considering that adults are more likely to be infected than adults.

Other indirect routes of transmission could occur if badgers are able to access cattle sheds or feed barns. If the disease was spread exclusively by this route mathematical models have predicted that incidence could be reduced by up to 50% simply by reducing access to pasture and buildings. However in 2005 a study surveying 151 farmers found that just 21 had taken steps to prevent badgers accessing farm buildings, with a further 75 stating that this is something they would never do or would consider impractical, so is it be implemented these days? Direct contact between badgers and cattle has been found to be extremely rare.

Additionally, looking at just one transmission route (from badgers to cattle) cannot account for the number of herd breakdowns (infections) seen. An additional route of infection must be occurring.

So we know badgers have the disease and can spread the disease, but here is the deal. So do cattle. The annual testing directed by the government towards high risk areas consists of the single intradermal comparative cervical tuberculin, or SICCT test. Cattle that test positive are culled, with the rest of the herd being placed under restrictions until the entire herd tests negative – at huge financial and emotional implications to the farmer (it is, after all, their livelihood). But this test has a major flaw, it’s accuracy level is averaging 72%. While that doesn’t sound that bad, a farm with small numbers of infected cattle could escape detection with this low sensitivity. Furthermore, newly infected animals are unlikely to test positive immediately post infection.

Cattle can also spread the disease between themselves. Like badgers, infected cattle predominately have lesions in the lungs and upper respiratory region, again implicating aerosol transmission as the most likely route. Infected and uninfected cattle housed together have shown that the disease can be transmitted between individuals. With herd sizes increasing over the last few decades, and cattle often being housed during wet weather to protect pasture, increased contact time in enclosed spaces could be increasing the chance of disease transmission. Larger herd sizes and a greater frequency of herd movement (cattle on and off the farm) are also found to be positively correlated with a herd incidence of TB.

“Ainville Friesians – geograph.org.uk – 50753” by Richard Webb.

Hang on, I thought badger culls reduced TB? During previous trials, when all badgers were removed from a high risk area (‘proactive’ culling), the incidence of TB was reduced. But crucially, it did not stop TB incidence completely. In areas where reactive culling took place (i.e. culling badgers near a farm in response to a herd breakdown) TB increased in neighbouring areas. This is because badgers live in social groups, and are often found in high densities with smaller territories is food rich areas such as pasture (loads of lovely earthworms etc). Yet while these groups are at high densities, they are also highly stable. Removing certain groups (‘perturbation’, or disturbance) upsets the natural boundaries, causing remaining groups to both roam wider and have increased skirmishes as territories are re-established.

So why shouldn’t we cull? Won’t it help? Also no. There are two main problems with this. Firstly, it is a short term solution. Without extensive geographical barriers (which the UK is not particularly well known for) or intensive re-culling at periodic intervals (which will certainly liven up country walks) badgers are likely to recolonize areas over time, especially if an inviting food rich habitat is sitting empty (areas subjected to proactive culling reached pre-cull TB levels 4 years after the initial cull). Additionally, there will still be TB!

This is because TB is  self-sustaining in the cattle population. Diseases are assigned an ‘R0’ figure, or basic reproduction number which indicates the average number of individuals an infected individual will infect in a population with no immunity to the disease. If it is below 1, the disease will not be self-sustaining and will eventually disappear. In cattle, the TB R0 figure is 1.1, meaning that it will increase without an outside infection source. Badger culling will not reduce this figure. This is backed up as during foot and mouth (when all TB testing was suspended) TB increased in cattle. It also increased in badger populations. When TB testing resumed, it decreased in both cattle and badger populations. So not only is the disease self-sustaining, cattle are also clearly infecting badgers too.

So how effective would a cull be on TB spread? Modern technique use modelling systems to assess this. One such study released this year, found that whether or not badgers were culled could account for just 5% of TB incidence in cattle (Moustakas & Evans, 2015) . That’s tiny! Instead, the main factors are the frequency of testing and the use of winter housing. What is important to note is that herd breakdowns often reoccur at farms, suggesting that unidentified infected cattle are being missed.

So how are new farms getting infected? Well in the UK, an estimated 30,000 cattle are moved daily. Additional modelling studies suggest that 84% of new herd incidences could be caused by the movement of infected animals, not badgers. A  small number of herds that are inefficiently testing for TB could be generating the majority of cases (Brooks-Pollock et al., 2014).

So if testing were increased both in high risk areas and with cattle being moved, this could potentially help identify more reactors and enable the infected cattle to be removed from the population, which could reduce the R0 value to below 1!

Why then, are the government proposing to cull badgers again? Pressure from the NFU and farmers is leading the government into sticking with a solution that in the past has provided a quick fix in the short term, despite modern evidence pointing to alternative solutions. It is also exceptionally costly. It is estimated that to clear an area of 150km2 of badgers would save £670,000, as TB herd breakdowns could be reduced from around 187 to 164 over 5 years (Jenkins et al., 2010) . Same it would cost approximately £2.14 million to complete the cull!

To summarise, it is clear that culling badgers is simply not the answer. Instead, increasing testing and reducing the indirect contact between species could be much more effective. It is a shame that people are unwilling to adapt in light of new evidence and also to  think of the long term bigger picture.

After all, we used to believe the earth was flat. People really have to move on!

Here, kitty kitty….

When asked about the worlds most endangered species, many people automatically think of creatures such as rhinos in Africa or Gorillas in East Africa. However one of the most threatened animals on the planet can be found right on our doorstep – the Scottish Wildcat, Felis silvestris silvestris. A regional subspecies of the European Wildcat (Felis silvestris) which is found throughout Europe, this characteristic version of an oversized tabby is in reality the UKs last remaining large carnivore, that has withstood threats that wiped out predators such as the lynx, wolf and bear. With some researchers implying that there are as few as 35 pure individuals left, this makes this elusive feline 17 times rarer than the Amur tiger and 45 times rarer than the Giant Panda. But with scientists in debate about what how to classify the Scottish Wildcat, the question is: how do you save a species when you can’t even decide what it is?

Picture: Michael Gäbler [CC BY 3.0 (http://creativecommons.org/licenses/by/3.0)%5D, via Wikimedia Commons

With its characteristic stocky build and distinctive pelage (coat pattern) this imposing tabby originally evolved from the first wildcat Felis lunensis 2 million years ago, creating the wildcat Felis silvestris. After the end of the last ice age (approx. 9000 years ago) the UK was separated from mainland Europe, isolating this island population. So far, so good. But from here on, things get a little complicated.

Defining the taxonomic group of the wildcat has met considerable debate. Are they a separate island subspecies (Felis silvestris grampia) or are they still just a regional population of the European Wildcat? Either way, they have been separated geographically for the last 9,000 years and, in the UK at least, this kitty is facing some serious problems.

In typical British (and to be honest, many other countries) fashion, over the centuries the majority of predators have either been exterminated or had their range dramatically reduced. The wildcat, which once ranged over the entirety of the mainland Britain, is now confined to the Scottish highlands where it remains highly elusive. A natural fear of man has been exacerbated by continued persecution such as hunting for pelts or for the often misguided belief that they would take lambs and other livestock (they are big, but not that big). Originally favouring woodland, the wildcat has at least adapted to hunting in a wider variety of habitats such as meadows and moorland. Its main prey are rabbits, supplemented by other small rodents plus birds and reptiles if the opportunity arises.

So what is holding the wildcat back? Surely now, they are unlikely to be hunted? After all they are now classified as a European Protected Species, making hunting and killing them illegal. Unfortunately they are still likely to be persecuted by gamekeepers if they come into contact with shoots. Feral cats make up 1.2 million of the 6 million cats present in the UK, and there are no laws restricting the culling of true ferals. In the heat of the moment, it is unlikely for a wildcat to look much different to a rather butch looking tabby to the untrained eye.

This leads us on to the main problem, hybridization with our pet felines. Introduced by the Romans 2000 years ago, our pet kitties were originally domesticated from combinations of the European, Near Eastern, Central Asian and Southern African Wildcats. Unfortunately this spectacular combination of morphological similar species means they can interbreed – and successfully produce fertile hybrids. With most species of the cat family being unable to hybridize due to physical or geographical isolation (for example lions and tigers only ever interbreed when ignorant fools introduce them in captivity) this unique situation is agreed to be the most devastating fact affecting wildcat survival in the UK.

So what does this mean for our wildcats? Well, for one thing it puts the identification of pure bred wildcats in the field on par with winning the lottery. Or at least, that’s what it must feel like. With such a reclusive species, the chances of seeing one are incredibly remote so alternative methods (such as camera trapping or live trapping) must be employed. Although its distinctive pelage can help with initial identification (for example, a pure bred wild cat should be free from white markings as this indicates it is a hybrid) a universal classification system of what a wildcat actually is seems needs to be established, although sadly this appears to be lacking across conservation groups. A minor point…

With an effective and well-designed conservation programme in place, steps can be taken to either remove domestic cats from the breeding population (i.e. via neutering), educating members of the public about the wildcat plight and establishing controlled captive breeding populations if needed. Saving the wildcat from with as few as 35 left may seem like an impossible task, but the Black Footed ferret and Mauritius Kestrel were recovered from populations of just 18 and 4 individuals respectively. There’s still hope yet.

There appear to be two main groups currently involved in the conservation of the Scottish Wildcat, ‘Wildcat Haven’ and ‘Highland Tiger’, both with rather different approaches. While I’ll leave you to make your own mind up (links below) personally I find the approach of the Wildcat Haven organisation much more logical. There is simply no point in saving or protecting hybrids. Should Australia stop protecting it’s Dingos and allow them to keep interbreeding with feral dogs? What’s the difference in having a load of lanky Labradors hanging around instead? Ok, maybe a bit dramatic. But you get my drift. I also feel that Wildcat Haven have the right idea in creating established areas were all feral domestic cats are neutered, eliminating the possibility of interbreeding. Whilst other organisations have advocated the culling of feral cats as a control method, I hardly see this as a conductive technique to getting members of the public on board with wildcat conservation. After all, en mass cat killing hardly goes alongside cat saving. But maybe that’s just me.

So the final key point remains, just why should we save them when they are so close to extinction? After a heated debate with a non-wildlife minded friend recently on this exact point, it really made me think. Do we not have a responsibility to protect our native species and, as an animal loving nation, what right do we have to project species conservation principles on other countries when we cannot protect our own? It is a shame that the Scottish Wildcat is not as cute as the panda, nor as majestic as say, the African Elephant, but it’s ours, and that should be enough. So maybe it’s time that this obscure feline hit the headlines more and got a bit of extra help before it’s too late.

Links:
http://www.wildcathaven.co.uk/
http://www.highlandtiger.com/