Bird flu – which birds (2)?

This blog follows on from an earlier post today.

I’m interested, mainly because I am interested in birds, but also because I am interested in ecology, and also because I have reason to be interested in the impacts of avian flu on poultry keepers, in how commercial poultry flocks get avian influenza and the role of wild birds in those events.  I suppose I’m also interested because back in 2007 I had a bit of an insider view of how Defra handled avian flu outbreaks  (see Fighting for Birds pp238-243) and at that time (a long time ago, yes) Defra clung, for far too long, to the public position that it was all down to wild birds when they knew that there was a far more likely source of infection.

When Defra talks about ‘wild birds’ being the main carriers of avian influenza I am sure that they are right but that is such a vague and all-encompassing category that it takes us nowhere useful in trying to figure out the best way to handle this issue to the benefit of poultry farmers and the public (both of whom pay the bills when outbreaks occur). And another reason I’m interested is that whenever you put the vets in charge of things it always seems to be wildlife that gets killed however complex the issue really is (Badgers anyone?).

So, those are reasons I’m interested. And my previous blog today pointed out that the images that Defra uses on this subject inspire no confidence that they understand what a wild bird is, and the data they release look as though they don’t tell us much either.

Part of the response that I got from APHA to my requests for information is this:


That useful-looking link is here – and one of the most interesting bits I have found so far is Table D.1 in Appendix D (it starts on p86) which is a list of the number of dead birds tested for avian flu virus and the % of them which were positive tests for the virus.  These are pooled data across the EU for all years 2005-2017 (up to April) but excluding 2011, 2012 and 2013.

It is the EU equivalent of the table in my previous blog which covered December 2016 – end of April 2017 for England, but for a vastly larger area and over a much longer period of time.

Have a look at it and it looks quite impressive because the numbers of birds are really quite large, and the number of species is really quite large too.  Given the sample sizes, it does appear to demonstrate the absolute role of ‘waterbirds’ in being likely vectors of avian flu (and, I’ll say it again, I’m sure that is very likely).

But look again with a birder’s eye and in that long list of species there are some interesting species.

Let’s take Sterna dougallii for example – one of my favourite birds, the Roseate Tern. Now, only three individuals were tested and all were found to be clear of the virus (negative results) but this is a species that is not present in Europe when avian flu is usually happening. Roseate Terns are in West Africa between October and April (at least). But, I guess, if you have a dead Roseate Tern or two to hand then it is absolutely worth testing them.

Another species that caught my eye was Fulica cristata – the Red-nobbed or Crested Coot – a very very rare European bird.  My easy-to-hand reference book, Birds in Europe is rather out of date as it was published in 2004, but that gives the European population as 80 pairs (which won’t be orders of magnitude wrong these days since the little devils are quite difficult to track down), and yet 310 individuals were tested (all negative).

The 28 Wild Turkey which were tested (all negative) represent a new species for the continent as does,  I believe, the 27 Horned Puffins (all negative).  This list is not a list of tested dead wild birds in the sense that you and I know wild birds, it clearly includes captive collections which aren’t farmed birds. So when we see that lots of Dalmation and White Pelicans have been tested, and quite a few Flamingos and an awful lot of ducks, we are now left wondering how many of these birds were wild wild birds and how many were captive wild birds. I’m sure someone must know, but it makes you wonder doesn’t it?

Given that this list appears to comprise of only dead birds, but dead birds that died in captivity and in the wild, and is pooled across all times of year (when avian flu was and wasn’t active in Europe) and from all years (including ones when avian flu was at a very low level) and from all countries (including ones where avian flu was at a very low level) then it strikes me as being a bit difficult to interpret.

However, I am interested to see that none of the 10,000 Pheasants tested positive (but where were they tested in which years?) even though we know that commercial Pheasant rearing facilities are prone to the disease – so that is interesting. And I am interested to see that none of the 229 ‘Italian’ Sparrows, 136 Spanish Sparrow or 1748 House Sparrows tested positive.

Perhaps the most amazing figure, and there must be a story behind it (maybe a story of a captive population? – but that seems unlikely to me), is the very high, 75%!!! , incidence of positive tests of Black-necked Grebes.  Does anyone know the story behind this? If you ever see a flock of Black-necked Grebes dive-bombing a poultry farm or walking down the drive to it, then that would surely be a cause of concern.

My point is, I find it difficult to find the evidence that points me to the role of wild birds in spreading avian flu (though I’m sure they do) when the data are of such a sort.  It’s a massive report so I may be missing the most telling parts so I’ll keep looking because this is where APHA told me I would find the evidence.


It is possible that they meant me to read p28 with the helpful title of ‘Most likely source of virus introduction’ – that sounds promising and it is surprising to find that it is the shortest section of the whole report (or close to the shortest) so here it is:

That’s it!

Member States were asked to guess (that’s my choice of word but I don’t think it is wrong) where the affected commercial premises got the disease from and most of them didn’t answer for most cases – so the overwhelming answer was ‘Don’t Know’ (86%) but for the rest, 14% of outbreaks, the Member State guessed ‘Wild Birds’ on 70% of occasions (that’s c9% of the total altogether) and since there is considerable doubt as to whether ‘wild bird’ includes ‘captive unwild birds in eg waterfowl collections’ then even that might be a bit of an overestimate.

I’m not convinced that these people know what they are doing.  But this report is a big report and if you can find anything interesting in it then do please put me right, or add petrol to my fire.














10 Replies to “Bird flu – which birds (2)?”

  1. “it always seems to be wildlife that gets killed”

    Foot and Mouth: 2001-2002: >6,000,000 head of livestock compulsorily slaughtered
    Bovine tuberulosis: 2005 – 2016: 404,593 cattle compulsorily slaughtered in GB

    1. Fair point well made Filbert.

      I was always interested in how no-one in Govt seemed bothered by deer during F&M. And, considering the fuss made about potentially disease-carrying beavers, how the importation of wild boar for farming (they’re carriers of every disease known to man and pig) was passed on the nod by MAFF. Call me paranoid, but I can see the benefit to vested interests in both omissions.

      I’d say c**k up rather than conspiracy when it comes to bird flu, but you have to know better to be guilty of c**king up. Sadly Defra today looks more like utter incompetence.

      1. I forgot the chickens.

        A visit to is time well spent, imho. A wonderful site with a reassuringly retro appearance. It is apparently in a state of hibernation but it may still have a download link for “Not The Foot and Mouth Report” – one of the cherries that Hislop did pick. It makes a good case for rounding up all the tame zoologists, microbiologists and epidemiologists that sucked up to the Blur Gubmint and confiscating their Sinclair ZX Spectrums and spreadsheet software

  2. Excellent pair of blogs! An interesting, if somewhat depressing demonstration of how ideas that are supported by the slightest of evidence can become entrenched as fact.

  3. I will have to dig deep and find a couple of articles I produced on this subject way back when. What was interesting, during a time when mainstream media was giving front page news to scare stories of how we would all die due to wild birds spreading bird flu, was the real cause for this virus spreading. It was a simple task to produce an overlay of main migration routes used by wild birds, then compare this to the actual spread of the virus. Surprise surprise there was no correlation between the two. Even more damning was using an overlay of routes used for the export/import of poultry, this produced a near perfect match to the spread of the virus. Was it less costly to blame wild birds?

  4. They (gov agencies) often make decisions that are selective and often puzzling , for example one which stumped me at the time and I still find problematic was in the aftermath of the Chernobyl fallout. Draconian restrictions were put into place for decades re. sheep which grazed on the moor but no restrictions on the shooting or movements of Red Deer and other game? The insidious power of the country set or simple incompetence?

    1. It was Napoleon who said (albeit in French), “Never ascribe to malice that which can adequately explained by incompetence”. Unfortunately, the exclusion of pheasant and grouse from any avian flu restrictions cannot be ‘adequately explained by incompetence’.

  5. Perhaps you may like to look at the FAO website from my tweet of 26/1/2017 – . Not just a matter of which birds but which virus and which birds. I have not checked for updates since then because all it did was confirm that wild birds can be affected by 16 types of influenza A viruses. You have only looked at 2 which the government is interested in (H5 and H7). You should also look at the history of Newcastle disease and pigeon paramyxovirus all of which were spread globally with birds, commercial or otherwise. Fortunately, in Europe, Newcastle disease can be controlled by vaccination but there are parts of the world where it does not work. However, ultimately, wherever people are involved the wildlife will suffer goes with being the top predator I guess. In our case through thoughtless destruction of habitat.

  6. The data is probably even less useful than you describe without good information on the nature of the dead bird incident. If, for instance, a dozen wigeon were all found dead together and all positive, a competent epidemiologist wouldn’t count them as 12 separate positive results. There’s no indication that is being taken into account is there? Likewise in a pheasant poult pen the odds are infection is going to be nonexistent or high with little in between.

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