Tag Archives: British Trust for Ornithology

What a difference a frost makes

Having bemoaned the lack of wildlife in my garden, last Saturday the weather turned very cold here and after replenishing the bird feeders they were flocking in in droves! These resilient little guys were obviously finding sufficient sustenance elsewhere until the cold set in but now they’re here in numbers daily, and today we have had 10-15cm of snow and it hasn’t stopped yet so I reckon they’ll be around for a while longer too.

One of the species which I have missed because they are normally here all through the winter is the chaffinch (Fringilla coelebs, Dansk: bogfinke):

The cock chaffinch always adds a splash of welcome colour

Chaffinch are resident breeders in the UK and can generally be seen and heard in trees and hedgerows all year round. Another resident breeder I hadn’t in the garden or in the countryside much this year was the dunnock (Prunella modularis, Dansk: jernsurv), the archetypal ‘LBJ‘ or ‘Little Brown Job’. When viewed closely they’re anything but LBJ’s. They feed on the ground so I always throw a handful of seed in the undergrowth for them. This little guy has been terrorised by my resident robin, but the arrival of a second robin has given him respite as my resident no longer has his eye on the ball.

My dunnock keeping one eye on the ground for seed while the other looks for the robin

The coal tit (Periparus ater, Dansk: sortmejse) is a pine tree specialist, seeking insects and spiders in the summer and seeds in the winter. This makes it a bit of a mystery here because we have very few conifers in the vicinity, but there are at least two flitting in and out of the garden all day:

The coal tit waiting it’s turn to get on the seed tray

A blue tit (Cyanistes caerulius, Dansk: blåmajse) about to join the coal tit and grab a seed

Starling – (Sternus vulgaris, Dansk: stær)

Starlings are a bird that used to be very common and would murmurate in humungous numbers but this only happens now in a very few places. When I was an undergrad in Liverpool they would gather on icy winters evenings over Old Haymarket in vast numbers. The aerial manouvres were breathtaking, as was the acrid ammoniacal stench from the guano left behind on the pavements! I generally only see them in small flocks of a few tens these days, but they regularly come and avail themselves of the fatballs in my garden. And they’re more than welcome!

And finally, usually the most visible diner at my avian restaurant, the ubiquitous blackbird. Even they were conspicuous by their relative absence until very recent weeks, but now they’re back in  numbers:

And no English garden is complete without a feisty blackbird (Turdus merula, Dansk: solsort). Having said that, according to the British Trust for Ornithology the blackbird is a ‘Migrant/Resident Breeder, Passage/Winter Visitor’ and they migrate within the UK but also in winter we get an influx from Europe coming from Germany and Poland and other parts of eastern Europe. It makes me chuckle that whilst us folk moan about the weather and then jet off to the Canary Isalands in the winter, the blackbirds are coming here to make the most of our balmy winter climate. Just goes to show, everything’s relative!

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Tits, tits, tits!

Coal, long tailed and great, that is, in case you were thinking the News of the World had reinvented itself in blog format! The reason I’ve dedicated a post to the tits is because they have been the most regular visitors to my feeders and on many days I’ve seen these four species there at the same time: blue tit (Cyanistes caeruleus, Dansk: blåmejse), great tit (Parus major, Dansk musvit), coal tit (Periparus ater, Dansk: sortmejse) and long tailed tit (Aegithalos caudatus, Dansk: halemejse).

Two factors combined to make photographing the songbirds in my garden considerably more challenging than is customary. Long periods of murky wet weather meant that the light was rarely optimal, and secondly, very few birds came to the garden at all up until November, and even then not in the numbers that have visited in previous years. I think the reason for that may have been the relative abundance of food in the countryside due to the mild and wet conditions that prevailed in the summer and autumn which gave rise to an abundance of blackberries, haws, sloes, hips and other berries. Then after November the birds started to reappear but the light didn’t improve so I took photographs at ISO settings of 1000-2000 to get the requisite shutter speeds, which is higher than I would normally use because of the higher background noise. Despite that I got some nice images:

Coal tit looking for a meal on a murky morningCoal tit looking for breakfast on a cold foggy morning

The coal tit is distinguishable at a glance by the prominent white stripe on the nape of its neck. They’ve been regular but infrequent visitors to my garden in other years but in the last couple of months they’ve been coming in ones and twos every day. The tits are not always easy to capture because they usually feed by grabbing a seed or nut and then flying into the cover of an adjacent bush to eat it. But just occasionally they linger for long enough, as this coal tit did. They prefer coniferous woodland in the breeding season where they feed on spiders and insects and in wintertime they are also prevalent in towns when they will also feed on seeds. Their conservation status is green, they’re resident breeders in the UK and can be found across Europe and Asia and in Africa too.

Long tailed tits disobeying the cardiologist!Two of a small flock of long tailed tits

As with coal tits, the long tailed tit is also immediately recognisable. Seeing one almost invariably means there are more close by. They fly from A to B one at a time, each following the previous one by half a second or so and are usually in small flocks of 10 or a dozen. I often hear them before I see them as they chatter to each other as they’re on the move. They like to feed on the fat balls I hang out, as do the other tits, and there can be 3 or 4 there at the same time with several more in the adjacent bushes, waiting their turn. They’re very charming little birds and I’m looking forward to them visiting on a bright sunny day so I can get some better images. Like coal tits they are also woodland birds, found across Eurasia they are resident breeders in the UK and their conservation status is green.

Great tit preparing himself to launch onto the seed tray

Great tits are probably the most regular partakers of the fare provided by my feeders, and that’s no bad thing, they’re handsome birds. There are a pair, male and female, feeding on seeds as I write, and they’ve just been joined by a pair of blue tits. The great tit is one of the birds that put the ‘song‘ in songbird, my Collins guide describes them as having a ‘rich repertoire’ and I’ve read they have around 70 different vocalisations, which suggests highly complex vocal communication for a small bird.

The male above has a chunk of peanut between his toes which he is pecking from. He is distinguishable from the female by the width of his black breast stripe which reaches as far as his legs, and the female below who has a very thin stripe which tapers downwards, is nibbling at a fat ball. In the depths of winter small birds need to spend most of the day feeding because the majority of their energy intake is used to maintain body temperature. Birds as small as a coal tit, which weighs 8-10g, therefore spend virtually all day feeding just to stay warm and they can die of hypothermia very quickly on a wintry morning if they don’t find food within a short time of waking up. So as us humans have destroyed so much natural habitat, our gardens and feeding stations are an essential lifeline for many species of birds.

Great tits also have green conservation status, numbering 2 million in summer 2000 according to the British Trust for Ornithology. Other species which have put in an appearance are the wren (Troglodytes troglodytes, Dansk: gærdesmutte), blackbird (Turdus merula, Dansk: solsort), dunnock (Prunella modularis, Dansk jernspurv) and a lone male blackcap (Sylvia atricapilla, Dansk: munk) flew through on one occasion – one of our eastern European overwintering blackcaps. Early one dark foggy morning as I was replenishing the feeders I caught a small movement out the corner of my eye so I glanced round without moving my head and a wren sat around 3 feet away watching me. When I finished I stood and watched him and he just waited for me to leave before grabbing some breakfast. I found out recently that wrens are our commonest bird, which really surprised me, but then they are adaptable and aren’t restricted to one particular habitat. It’s nice to see them flitting around the garden in their perpetual search for insects to see them through the winter.

(N.b. I source my bird feed from Vine House Farm. I wouldn’t normally do a free plug but I really like what these people do. They work together with the Wildlife Trusts and they farm the land to produce bird feed in the most wildlife-friendly way they can, and they publish a free newsletter to update on progress and news from the farm. Their feed is not always the cheapest but I’ve always found it to be very high quality.)

Flowers and foliage

The greatest thing about a sodden Springtime was the abundance of bloom that resulted. So I spent alot of time this year recording the wild flowers and foliage that flourished in the wake of the deluge.

Some years ago I attended a lecture in which the speaker said that due to modern farming methods which involve the use of mechanisation and toxic chemicals to create a sterile monoculture,  verges and drainage ditches have now become an invaluable seed bank where many of our wild flowers can still prevail. Without these unpolluted conduits criss-crossing the countryside the flora seeking refuge there would be even more threatened. This idea seems to be born out in my local area as the drainage ditches are indeed full of wild flowers year on year.

Hedge woundwort – Stachys sylvatica

Hedge woundwort has lined the field margins and ditches in greater abundance this year than in previous years, its delicate purple flowerheads, growing up to around a metre tall, poking  over the top of the ditches. It’s a lovely flower and it gets its name from its preference for hedgerows and because the crushed leaves were traditionally applied to wounds to stem bleeding.

Hawthorn flowers lined all the hedgerows ealier in the year and heralded a glut of berries which are currently providing rich pickings for the birds, and will continue to do so well into the colder months.

Hawthorn blossom – Crataegus monogyna

The October 2012 edition of British Trust for Ornithology’s BirdTrack reveals that the migrant redwings (Turdus iliacus, Dansk: vindrossel) should be arriving here from Scandinavia any day now and will be followed closely by the fieldfare (Turdus pilaris, Dansk: sjagger), and the hedges fulls of haws will help to replenish their fat reserves after the migration across the North Sea. I think I saw my first redwing over Histon on Sunday, they have a characteristically undulating flight during which they fold back their wings and form a teardrop shape, which is what my sighting today was doing. So the fieldfare should be along soon too, according to the BTO.


Oxeye daisy – Leucanthemum vulgare

Oxeye daisies are my Mother’s favourite flower and she has been pestering me to publish a picture of one. This year they lined my cycle route to work alongside the Cambridge Guided Busway in their thousands so I’m finally able to complete my commission. So, Ma, this one’s yours!

The wild flowers have been spectacular but the leaves and some of the trees have also been contributing their own splash of colour to the countryside such as the cluster of oak leaves below.

(Dramatic interlude: Wow, the first goldfinches (Carduelis carduelis Dansk: stillits) arrived on my niger seed feeder a couple of days ago after being absent through the summer and until a minute ago there was an adult and a late fledgling feeding there. I just caught a blurr out the corner of my eye as I was writing this post and looked up just in time to see a sparrowhawk (Accipiter nisus, Dansk: Spurvehøg) swoop through a gap in the buddleia bush next to the feeders, the goldfinches fled but it all happened too fast to see if the hawk was successful. It was all over in less than a second!)

Back to the oak leaves though, they were lovely colours, almost autumnal. Oak trees are amazing organisms, in fact they are substantially more than organisms, they are ecosystems in their own right. They live to be several centuries old and when coppiced or pollarded (pollarding is pruning back a tree to the top of the trunk to promote new branch growth, compared to coppicing which is pruning it back to ground level), but there are numerous examples of oaks living for 1000-1500 years. And they become home to hundreds of other species of fungi, lichens, insects, birds and mammals.


Oak leaf cluster – Quercus robur – the English oak

And right next to the oak was this gorgeous, delicate field rose. The field rose, Rosa arvensis, grows in hedges and has white to cream coloured flowers and lovely golden yellow anthers. It flowers later than the dog rose (Rosa canina) which has pink flowers and the leaves are smaller. Later in the autumn the flowers turn into bright red hips which provide food for birds as well as humans. When I was a kid we used to have rosehip syrup which was sweet and delicious and I’ve been toying with the idea of trying to make some. If I succeed in creating something pleasant I’ll post the recipe here.

Without doubt my favourite wild flower is the field scabius (Knautia arvensis). I think they’re utterly beautiful and if I have a camera to hand I struggle to walk past one! Fortunately for me the field margins around here are replete with them so I’m rarely short of photographic opportunities.

The glorious flower of the field scabius

And from side on:

The hue of the flowers can vary from a pale pastel shade to quite dark purple. Each flower contains male stamens which can be seen protruding from this flower from between the female florets. The stamen consists of the filament (the stalk) and the anther (the pollen bearing part at the end of the filament). The stamens die back before the female florets mature in order to prevent self-fertilisation. Field scabius is named afer the German botanist Dr Knaut and has historically been used to treat skin ailments such as scabies and eczema.

Titchwell birds – the final episode

I’ve posted several times with pictures from my trip June to Titchwell on the north Norfolk coast but I’ve now exhausted my photo collection from that trip so this is the last one. There was a terrific number of bird species present the day I was there including ducks, waders, raptors, passerines and gulls, but the wildlife wasn’t confined to birds, a wall brown butterfly and a chinese water deer also putting in appearances.

Gulls are many and often not-so-varied and can be easy to overlook: “What’s that bird?”, “Oh it’s just a gull”. But I like gulls and and it’s always good to have a new species identified and on this trip it was the little gull (Hydrocoloeus minutus, Dansk: dværgmåge). At first glance the little gull looks like a black headed gull, but it is noticeably smaller:


Little gull in winter colours – the summer plumage includes a completely black head

The other obvious difference between the two species is the colour of the beak which is black on the little gull and red on the black headed. It may also be mistaken for a tern as it swoops down on the water in a similar way to a tern but it’s not fishing it’s picking food from the surface of the water. I haven’t seen other gulls feed in this way.


Black headed gull (Larus ridibundus, Dansk: hættemåge)

The black headed gull is common and I see large flocks of them feeding in the fields around Cambridge in the winter, unlike the little gull which is a rare breeder in the UK and a passage and winter visitor on it’s way to the Mediterranean.

Grey heron (Ardea cinerea, Dansk: fiskehejre)

Stalking the shallows were several grey herons searching for fish and amphibians. The heron is a very effective predator unlike the pied wagtail perched just a few metres away serenading the comings and goings of serried ranks of twitchers passing to and from one of the hides:


Pied wagtail (Motacilla alba, Dansk: hvid vipstjert)

This wagtail is an adult male, his colours are much darker and the black bib more extensive than the more delicately shaded female. The pied wagtail is a resident and migrant breeder and I regularly see them patrolling lawns, meadows and carparks with their characterisitic twitching tail.

The one bird which I knew could be seen at Titchwell, but which I also knew was very elusive, so I didn’t really expect to catch a glimpse of it, was the bearded tit (Panurus biarmicus, Dansk: skægmejse). It’s one of those birds that I’ve seen pictures of and thought it almost looks unreal, like a childs drawing of an imaginary colourful songbird. A notion which seemed to be corroborated when I looked in my Collins field guide and it wasn’t listed! It transpires that it was listed, but as the ‘bearded reedling‘ instead of the ‘bearded tit‘, and it’s actually more closely related to the larks than the tits, to which it’s resemblance is only superficial. Despite the alternative name in my field guide it is listed on the British Trust for Ornithology ‘BirdFacts‘ website as the ‘bearded tit


Bearded tit juvenile

The bearded tit is resident in the UK but confined to the southern and eastern extremities. However, I did see some and even managed to get a photograph, albeit a not very good one(!). This one is a youngster, identified by the black eyestripe which differentiates it from the female, and the black patch on the nape which is absent in both adult genders. Of all the birds I saw on this visit the bearded tit (or reedling) was probably the highlight.

Apodidae – the swift

Last month I spent a day at the RSPB reserve at Titchwell near Hunstanton on the north Norfolk coast. It’s a particularly dramatic bit of coastline and is home to a very impressive array of birdlife which is concentrated here on the reserve. As well as all the waders and other water birds squadrons of swifts were wheeling and zooming low over the water plucking insects out of the air.


Swift – Apus apus. Dansk – mursejler

Swifts have been declining in numbers and their conservation status is amber, but it was difficult to believe they’re struggling! There seem to be good numbers of them in the skies around Cambridge too. I love it in the summer when I open a window and the sound of shrieking swifts filters down from on high.

Insects beware, bandits at 6 o’clock!

Photographing swifts in flight is challenging to say the least and something I’ve never before had much success with, but there were so many of them at Titchwell and they were flying close to the ground so I gave it a go. They seemed to have preferred routes which I guess were dictated by where the insects were flying and that made getting pictures a little less tricky as their flight paths were more predictable. And here are the results.

Swifts are members of the Apodidae family and on ther face of it appear fairly similar to swallows and martins. But my oft ill-remembered scchoolboy Latin leads me to believe that ‘apodidae‘ means ‘lacking feet‘ whereas swallows and martins are passerines which means they have feet adapted for perching. Swifts do have feet but they are tiny and adapted for clasping and not perching, all four of their toes pointing forward. One thing that the three species do have in common is that they are all awesome aeronauts. A juvenile swift can spend up to three years aloft after fledging and it will spend most of its life on the wing: eating, sleeping, gathering nesting material and even copulating in the sky.

According to the British Trust for Ornithology swifts shut down their brains one side at a time in order to maintain stable flight. But I’d like to know how they found that out – I can’t think of an experimental design that would enable this conclusion!

The swift is a summer migrant to UK shores and they spend their winters in South Africa, and I suspect the journey doesn’t take too long, covering a thousand miles in a couple of days!

My day at Titchwell was gorgeous, it was during the foul wet weather we’ve been having but shortly after we arrived the sun emerged and stayed with us for the whole day. I took nearly a thousand photographs and I’m going to post the best of them in batches in the next few weeks, interspersed with some other local wildlife. I hope you like them!

Serendipity II – The charismatic cuckoo

I don’t recall having seen a cuckoo before, even though I’ve heard their unique call many times. But on my sojourn over to Wicken Fen a couple of weeks ago there were lots of them. ‘Lots‘ is a relative term because cuckoos are becoming increasingly scarce, their conservation status is red due to recent declines in the breeding population and in 2000 there were 9.6-19000 breeding pairs in the UK. But on this trip we heard and saw at least 5 and possibly several  more.

Just before I spotted the first cuckoo I glanced across the lake and this was the view:


A pair of shoveler in the foreground, a little egret behind and a roe deer just beyond the reeds

I really like this picture because of the colours of the reeds and the water in the evening sunshine, but also because it contains three interesting species. Apart from rabbits, any wild mammal is exciting to see in this country, so the roe deer was a pleasing encounter. The little egret (Egretta garzetta, Dansk: silkehejre) is a member of the heron family which is now resident in the UK, presumably as a result of climate change. I associate them with warmer places because that’s where I saw them before 2000, but nowadays they’re not particularly uncommon here. And in the forefround are two shoveler (Anas clypeata, Dansk: skeand) which are migrant visitors to the UK, but this pair obviously liked it enough to linger and are still here in the middle of May, long after they would normally have left.

And then there were the cuckoos:


A pair of cuckoo, Cuculus canorus, Dansk: gøg

The cuckoo is an incredible bird and until very recently it was poorly understood. Last year the British Trust for Ornithology (BTO) managed to tag five male cuckoos with tiny satellite tracking devices and found out that they headed to the tropical sub-Saharan rainforests of Cameroon and the Democratic Republic of Congo. The cuckoo arrives back in England from Africa in late March or April and departs in July or August. It leaves earlier than other species because its parasitic breeding strategy removes the need for chick rearing. That means the cuckoo spends a minimum of 8 months a year in Africa so to call it a British bird is, I suppose, less than accurate, even though it breeds here.


The classic hanging wings pose which I always associate with the cuckoo

The tagged birds were all fitted with solar powered devices which transmit location data once every 48hr. The tracking data revealed that all five birds headed south over France and across the Mediterranean before heading down across Africa to Cameroon and DRC. All five made it. One of the birds died in Cameroon and two more died on the way back, but two of the five made it back to East Anglia this year. I believe the BTO plan to tag more birds including females and I’m very keen to see the results of that experiment.

The cuckoo is an iconic bird in the UK and it’s call is very distinctive. The call is generally recognised as a signal that Spring has arrived and there are local traditions around the UK based on the cuckoo. It is said in Worcestershire that the cuckoo is never heard before Tenbury Fair on April 21st or after Pershore Fair on June 26th. The song actually changes in June from the characteristic ‘cuck-coo‘ song to a shortened ‘cuck‘, and there is a rhyme about this:

In April I open my bill
In May I sing night and day
In June I change my tune
In July far far I fly
In August away I must

My Dad remembers a similar rhyme he used to sing when he was a kid in the 1940’s which was essentially the same but with some local Northamptonshire words substituted in.

I’m not quite sure what these two were doing but they were acting as a pair, and every minute or two one of them would dive off into the adjacent reedbeds to return a minute or so later. As I mentioned above, cuckoos are parasites and they could have been looking for nests to parasitise. There breeding strategy is unique, at least as far as I know. They lay their eggs in the nests of one of three other small songbird species: the reed warbler, the meadow pippit and the dunnock. All of these are the size of a sparrow (ish) so are much smaller than the cuckoo which is dove-sized, which I guess guarantees that the cuckoo chick will be much bigger than its ‘siblings’ and it won’t be threatened. The cuckoo chick then ejects the other chicks from the nest to die and the parents assume it is one of their own and feed it until it fledges. I’ve seen film of a cuckoo chick turfing out the other chicks and it’s a remarkable process, and not particularly pleasant to watch!

Despite their unsavoury procreation habits they are spectacular and charismatic birds and I hope the BTO research can find ways to guarantee their continued return here to brighten up the Spring and Summer.

Carduelis (or Chloris) chloris

A sound I hear frequently at the moment when I open a door or a window which stands out from all other birdcalls is the call of the male greenfinch. It’s quite variable in tone from fairly high pitched, as in the recording here, to lower pitched where it almost sounds like a whirring mechanical toy.

The bird in these pictures has a reddish hue to it because it was being lit by the evening sun as it was getting lower in the sky, and also from the reflected light of the rusty ironwork and insulators of the electricity supply cables:


Greenfinch male calling from the top of a telegraph pole

The female greenfinch is similar to the male but her colours are much more drab, she is darker grey/brown without the vibrant green of the male.

The greenfinch is a resident breeder in the UK and can be found in gardens and parks at all times of the year feeding on bigger seeds and sometimes insects when rearing youngsters. It has a chunky beak which is typical of finches and is custom built for cracking open seeds.

The taxonomic name for the greenfinch is listed in some references as ‘Carduelis chloris‘, as in my RSPB ‘Complete Birds of Britain and Europe’ by Rob Hume published in 2002, (RSPB – Royal Society for the protection of Birds) ISBN 0751373540, and also in the RSPB Bird Identifier website. But in the BTO BirdFacts website (BTO – British Trust for Ornithology) and in my Collins Bird Guide 2nd edition from 2010, ISBN 978 0 00 726726 2, it is listed as ‘Chloris chloris‘ (Dansk: grønirisk). Somewhat confusingly the BTO entry goes on to explain that the name derives from ‘carduelis‘ meaning ‘goldfinch’ and the Greek ‘khloros‘ meaning ‘green’. So it appears that the two names may be interchangeable. Incidentally, the chemical element chlorine also derives its name from khloros as it exists as a green gas.

He’s turned round to keep on eye on me – his seed-cracking beak clearly visible

The poor old greenfinch has taken a bit of a battering in the last few years since 2005 from the trichomonad parasite which causes a disease called trichomonosis. This microscopic parasite lives in the upper digestive tracts of several birds species including other finches, house sparrows (Passer domesticus, Dansk:  gråspurv) and pigeons and doves. I’ve heard that feeders may become contaminated by pigeons from where it infects the smaller birds. It’s particularly unpleasant (as are most parasitic infestations!) because it causes the throat to swell to the point where the birds can’t swallow so they eventually die of starvation.

Fortunately I’ve never seen any evidence of infected birds but if you think you may have a problem you can click here for the RSPB advice sheet which has details on how to identify the problem and how best to deal with it.

The balance of nature

At the end of May this year the BBC screened an episode of Countryfile in which John Craven interviewed a member of the scientific staff at the Game and Wildlife Conservation Trust (GWCT). Taking things literally I’d assumed the this was a trust who’s aim was the conservation of game and wildlife. However, as the interview progressed I began to question this assumption as the discussion centred around a study to be carried out by the GWCT in which magpies were to be eradicated from a specified test area to assess the local effect on songbird populations. I don’t think that removal of a native species such as the magpie by trapping and killing them is an ethical way to study predator/prey relationships. But is it scientific?

The magpie – villain of the piece – apparently

The interviewee from the GWCT, Dr Jeremy Stoate, justified the cull on scientific grounds suggesting that increased predator numbers result in significant reductions of prey populations and the species they identified as being largely responsible was the magpie.

Magpies are bold, brassy, ubiquitous, and are generally percieved as being a tad raffish. They undoubtedly predate songbird nests, but I struggled to understand how this could justify slaughtering them. Numerous other species of bird and mammal such as sparrowhawk, kestrel, owls, great spotted woodpeckers, rats, stoats and probably the biggest killer of small birds, domestic cats, all predate songbirds and some raid nests to poach eggs and chicks.

So why was it only magpies that were to be exterminated?

The action was being justified on a scientific basis, and whilst I’m no ecologist, I am a scientist, and the whole thing seemed unscientific, so I decided to do a little research of my own on the subject. Interestingly, since I did my initial research in June, it appears that references to the study on the GWCT website have been taken down. At least, I couldn’t find any.

However, what I did find out was that the study was commissioned and financed by another ‘conservation’ organisation called Songbird Survival. Whilst I believe that GWCT do have a genuine interest in the countryside as a whole, the same cannot be said for Songbird Survival. It is a registered UK charity whose statement of activities on UK Charity Commission website is this:

THE PRINCIPAL OBJECTIVE OF THE CHARITY IS TO IMPROVE, PROTECT AND PRESERVE FOR THE BENEFIT OF THE PUBLIC THE POPULATION OF SONG AND OTHER SMALL BIRDS BY THE CONSERVATION AND RECREATION OF HABITATS, BY SUITABLE EDUCATION OF THE PUBLIC AND LOBBYING MP’S AND THE HOUSE OF LORDS, TO EFFECT CHANGES IN THE LAW WHERE WE FEEL IT IS NECESSARY.

However, the details on the Charity Commission website also list the trustees, and that makes interesting reading too…

LORD COKE, MR CLIVE PATRICK SHERWOOD, MR FRED VALENTINE INGRAMS, MR JOHN RICHARD PUGH, LORD MICHAEL RICHARD RANKEILLOUR, MR ROBERT JOHN MIDDLEDITCH, MR DAVID GRIFFITH, MR NICK FORDE, LORD JOHN HADDINGTON, MR HUGH VAN CUTSEM, MR COLIN STRANG STEEL

All of these trustees are big landowners, or relatives of landowners, some with shooting estates, and they all support hunting and shooting. Lord Coke is the owner of Holkham Hall in Norfolk and he and several of his gamekeepers have been prosecuted for killing birds of prey by shooting and poisoning. So I’m struggling to believe that these people really have the best interests of songbirds at heart when they are funding ‘scientific’ destruction of a single predator species which has been implicated in taking gamebirds. And via the titled gentlemen listed as trustees they would be ideally placed to carry out their stated aim of ‘lobbying MP’s and the House of Lords‘.

Back to the science though. I recently attended a lecture in which Dr Mike Toms of the British Trust for Ornithology (BTO) talked about garden birds and how gardens are becoming an increasingly important sanctuary for increasing numbers of songbirds, and therefore predators, such as magpies, great spotted woodpeckers and sparrowhawks. In the course of his lecture Dr Toms talked about the decrease in songbird numbers and how magpies were being blamed but said that magpie predation was not the cause of the decline in numbers but habitat destruction and current agricultural practices were the primary reasons. I emailed Dr Toms and he was kind enough to send me several links to published work by the BTO into bird predation. This list included this publication: ‘Population changes of avian predators and grey squirrels in England: is there evidence for an impact on avian prey populations? Journal of Applied Ecology 47: 244- 252‘ describing a collaborative study between the BTO, GWCT and the University of St Andrews in which the impact of 2 groups of predators, those which predate adult birds and fledglings and those which predate nests (including the magpie) were analysed for 29 prey populations. Quoting directly from this paper:

For 22 avian prey species, there is no evidence that increases in common avian predators and grey squirrels are associated with large-scale depression of prey abundance or population declines‘.

Then:

Unexpected was a large number of positive (my italics) associations between predators and prey, particularly for native avian nest predators, which largely exonerates these predators as driving declines in passerine numbers

And:

Analyses of large-scale and extensive national monitoring data provide little underlying evidence for large-scale impacts of widespread avian predators and grey squirrels on avian prey populations…

The paper also describes negative correlations between the remaining seven prey species and predator numbers, and accepts that some of these may be causally related. Although e.g. the relationship between sparrowhawk and tree sparrow is probably significant, that between buzzard and goldfinch almost certainly isn’t. However, in an email from Dr Toms to me he indicates that the GWCT study showed negative causal relations on  a local level but, crucially, not at a population level.

This last point is key to the argument. In a study of population dynamics, if conclusions are to be drawn about overall depletion of numbers in response to a specific influence small local studies cannot be extrapolated to enable conclusions for the population as a whole, and to do so is erroneous at best, misleading at worst.

Incidentally, I also found a publication on the website of Songbird Survival entitled ‘Detecting an impact of predation on bird populations depends on the methods used to assess the predators’, (Methods in Ecology and Evolution (2010),1,300-310, Nicoll M., Norris K.). This is an interesting paper because rather than analysing actual population data it investigates the methods used to analyse the data. And in the summary the last point recommends: ‘…the findings for studies which use opportunistic data, for a limited number of predator species, should be treated with caution and that future studies employ bespoke census techniques to monitor predator abundance for an appropriate suite of predators.’

This is interesting because it argues that the methods used to analyse opportunistic, observational data must be carefully optimised to ensure that conclusions drawn from the data adequately reflect the observations.

None of the publications suggest that slaughtering the predators is a rational scientific way to assess the negative impact on prey species. And I’m inclined to think that culling is poor science, particularly as the latest evidence suggests predator numbers don’t reflect negatively on songbird populations and in some instances there is actually a positive correlation between predator and prey, presumably because the predators remove the sick and the slow before they can add their DNA to the genepool.

I think the notion that predators destroy prey populations is bizarre because I was taught, and importantly, I believe it to be the case, that prey abundance determines predator numbers, not vice versa. If prey numbers decline then shortly afterwards so do predator numbers. Taking the reverse of this theory to it’s logical conclusion, if predator numbers determine prey numbers, all prey species would eventually become extinct and then the predators would also become extinct and the balance of nature which has prevailed for the last few billion years would be turned on its head. Which is absurd.

So population studies which are centred around the slaughter of predators seem to me to fly in the face of all current theory and are therefore morally indefensible aswell as being scientifically unsound, especially when commissioned and financed by such obvious vested interests as Songbird Survival.