Wednesday, 4 January 2012

Ruddy Ducks - How informed are you?

Recently I have seen a lot of shit spouted about Ruddy Ducks on various listserves, facebook pages and forums. I have seen threats to beat up those that endorse or aid the cull. It all seems ridiculous when you look at the science and legal obligations of the UK. Here is my attempt to untangle the web of bollocks talked about it. I am not involved in the Ruddy Duck cull in any way but I do fully endorse it as an unsavoury but necessary action.

male Ruddy Duck

Firstly a bit of history. About 70 Ruddy Ducks escaped from collections in the 50s and this dropped down to an estimated 20 birds by 1962. WeBS data suggests that there were 6,000 birds by 2000. Birds were first recorded in mainland Europe in 1965 and a wintering population of over 200 birds were recorded in France. That these birds eminated from the UK is indisputable as the French breeding population peaked at 20 pairs. Numbers peaked at 7 pairs in the Netherlands. By 1984 the first birds were recorded in Spain and between 1984 & 1999 a minimum of 139 birds were recorded in Spain at 43 localities. These must have been British in origin due to the numbers and genetic studies showed this to be the case (British Ruddies are a pretty undiverse lot genetically). So pre-cull we have Ruddy Ducks occuring at a rate of about 10/year in Spain and 6000 birds in the UK with maybe 100 other birds in the nations to the south of the UK. At this point there had been NO recorded vagrancy of Ruddy Duck in the eastern Atlantic. There has been a single subsequent record, of a female on the Azores in 2009.


male White-headed Duck

A brief look at White-headed Ducks shows that numbers dipped to 22 pairs in the seventies but thanks to the protection of a number of sites they currently number 2,600 pairs approximately. This represents 25% of the world population and all of the European population. Birds are restricted to sites in the south and east of the country and breed in emergent vegetation fringing small eutrophic lakes. 84% of birds breed in protected areas.

Now a bit of biology. Ruddy Ducks outcompete male White-headed Ducks when they share territory. Ruddy Ducks are preferred by female White-headed Ducks to the males of their own species. In addition Ruddy Ducks are more aggressive when courting making them more likely to win an territorial battles for females. Thirdly, unlike White-headed Ducks but in common with many duck species, Ruddy Ducks will have forced intercourse (rape) with females including female White-headed Ducks. Basically when in direct competition Ruddy Ducks win hands down against White-headed Ducks when it comes to breeding success. And here is the shocker - hybrids are viable to at least the third generation. Those Ruddy genes are in the population and not getting out. So the big question is then - would it happen in the wild? Well 59 hybrids were recorded to 1999 at 23 different sites. Thats a lot. Ruddy genes are not thought to have introgressed yet as culling of Ruddy's and hybrids occurs in Spain but it only takes one or two broods to remove pure White-headed Ducks from a discrete area by introgression. I have heard people say - why cant we just cull birds in Spain. They do but Ruddy Ducks kept arriving and as mentioned above due to the viability of hybrids the gene pool would quickly get diluted by Ruddy genes if any were missed - better to treat the cause at source. Eradicate alien Ruddy Ducks.

Now for some politics. The UK is part of the EU and as such is a signatory of the EU birds directive (you know, the one we use to berate Malta about) and as such we are bound by the Bonn and Bern conventions. We are also a signatory to the African-Eurasian Waterbirds Agreement (AEWA) which includes White-headed Ducks. This means we are legally obliged (and rightly so) to conserve birds named in these agreements (which White-headed Duck is). I have heard people moan about shooting of the Ruddy's but a feasibility study showed that oiling eggs and other measures were not effective due to the population size. The Ruddy Ducks had to be removed. That is killed if you dont dress it up.

So in summary. We let Ruddy Ducks become established. They did. They went to Spain. They outcompeted the recovering White-headed Ducks and threatened to dilute the gene pool as hybrids were viable. We eradicated (more or less) Ruddy Ducks through shooting. White-headed Ducks are significantly less threatened. Where is the problem? There are plans to clean up the few remaining in Britain and the near continent. Is LGRE upset about the loss of a year tick? Maybe when White-headed Ducks have spread to the camargue and western France and are regular vagrants he will be less vehement? I support the cull. Do you? If not why not?

some links:

Defra report

Genetics Study

Study for Possible Vagration

Feasibility Study




8 comments:

Tim Jones said...

Are any other countries culling there Ruddies, France, Netherlands?

James said...

I believe the Dutch have sanctioned a cull. Not sure about the french.

yorkshirebirds said...

An excellent post James. Spot on. There are too many escaped wildfowl knocking about anyway. I look forward to your piece on cuddly rats. Don't forget that one of objections to the proposed re-introduction of Sea Eagles to Suffolk was that it would scare pigs. Almost enough to turn you vegetarian but where would we be without turkey twizzlers? answers on a postcard

Tim Allwood said...

Well said. Doubt you'll change any minds though James. Just shoot the fuckers. They're getting scarce over in Norfolk now though. I do the Ruddy for the county bird report and despite it being difficult to know how much info is being withheld by misinformed cheese-brained robin strokers, it does seems as if there's an inexorable decline taking place.

The sight of WHD on lakes in Spain and Turkey is fantastic. Can't think of a better resident duck...

James said...

Thanks for the kind words guys. I didnt think it would convert any hardcore Ruddy cuddlers but feedback from some people who sat on the fence is that the summary seems to have clarified a lot of the issues some had with the cull which can only be a good thing.

I feel honoured Mr Allwood having a comment on the blog. Glad you approve. If you are still doing occasional work then our paths may cross as I now do some stuff for a Norfolk based company that I am sure you know of. Still being the midfield general? Sadly Im more Jan Molby than anything else these days. Take it easy.

James

Tim Allwood said...

Hi James

still teaching/stay at home dad (wonderful wife!), very occasional survey work but onshore currently. Still footballing too (just local league), but now very much ensconced in middle of the back four. The 'Libero' I think our continental friends call it. The legs are failing slightly now...

Looks like you're enjoying fatherhood too James!
best
Tim

RKB said...

It's amazing how fickle birders are about culling. Mice on the South Atlantic Islands = fine, but Ruddies in Europe? No way. It's scary how much scientific literacy is plummetting, yet how much pressure public opinion can have (cf Eagle Owls). It's a waste of time/money culling grey squirrels now though - much too late. No chance of saving Reds on the mainland, and, apart from them, Greys have no proven conservation implications (they've replaced Reds, that's all). So no point in killing them for the sake of it. Save the bullets for fights we can win.

Gavin Haig said...

Hi James

Nice summary of the RD story, thanks.

Do I support the cull? Despite the risk of Tim labelling me a cheese-brained robin-stroker, no. Why not? in the broadest terms of what's really important it was a daft waste of money, and I am sure you can think of a million better ways to have spent it.

I am constantly dismayed by our arrogance. For a long time we have stomped all over this planet, whimsically deciding which creatures may live, and which must die, which are 'good' and which 'bad'. Many successful ones we label vermin. Clearly we have the intelligence (and therefore right) to hold this office - after all, look around - we have such a fine record of stewardship...

James, you may detect a cynical note, so don't take me too seriously. It's not so much the cull I feel is wrong, more the premise that led to it.

Did someone mention science? Surely no support there? The genetically feeble WHD clearly had it coming, and is undoubtedly for the chop one day... ;o)

How brains and birds become mutually exclusive