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Who To Believe? (2 Viewers)

Anthony Morton

Well-known member
All too frequently some interesting and factual postings have a habit of becoming lost in the tide of 'squit' which ensues when a thread takes off. I believe an example of this is contained in the 'Hunting -v- Birdwatching' thread, which I have extracted as I feel it warrants further debate. For ease of reference, however, I have also included the relevant posting numbers on the original thread.

In Posting # 117, StevieEvans wrote that in Spring 2003 two Larsen traps were set on his farm. The target species was the large number of magpies which had emptied many songbird nests in previous years. Within four weeks the traps had accounted for 28 magpies and 1 crow, still leaving two pairs of magpies. Last year (2003) and especially this year (2004) a "huge boost in the number of songbirds" has been noticed.

In response to a query, he confirmed at the beginning of Posting # 179 that the trapping had done "... what we wanted and achieved the songbird results we wanted too." He also mentioned that he did not envisage having to trap the magpies again for the forseeable future.

In his Posting # 193, Ian Peters tells us that to have any effect on songbird numbers it is necessary to eliminate the predator population completely. He also mentioned that, when viewed from a mathematical perspective, a re-examination of population dynamics clearly showed that prey populations influence predator populations, and not the other way round.

These appear to be two opposing views. On one hand the evidence is based purely on first-hand personal experience, and on the other the scientifically-backed results obtained from previous studies. Which one is correct?
 
Last year my next door neighbour had to give up Larsen trapping of Magpies, due to advancing years (I was given the Larsen trap to convert into an extra nestbox for the hens).

This year there has been a considerable increase in the numbers of songbirds in the area.

This isn't evidence that trapping Magpies actually reduces songbird populations. The increase in songbird numbers around here is probably because there was finally some decent weather at the critical time in the breeding season, May, June and early July. The fact that B happened after A is not proof that B was caused by A.
 
I can't see the point of this

I can't see what it will 'prove'

most people who are aware of the 'facts' wil probably keep out of the debates as there seems to be little point in entering them.

As to the point above, ecology is a complicated business and neither of those posts above will be 'true' - it will be much more complicated than that.

Science is of course necessary to validate observations and if you think not then you're onto a loser and risk looking silly. Casual observations may of course be representative of the true situation but just saying ' i saw it so that means my opinion is obviously true' will rightly carry no weight.

In general terms of 'hunters v conservationists' for want of a better term, the vast majority of the science does seem to back the conservationist view. Most articles published in respected journals support these views as well. Very few people appear to working on opposing ideas, trying to prove the conservationist view point wrong. You can find several reasons for this if you wish but the long and short of it is that those points appear to hold little weight and therefore are not worth investigating as a long term study.

there,
shan't be revisiting this one to post either.
 
Tim Allwood said:
I can't see the point of this

Then why bother to post?


I can't see what it will 'prove'

most people who are aware of the 'facts' wil probably keep out of the debates as there seems to be little point in entering them.

So how can the rest of us mere mortals hope to learn anything from the experts if they won't pass on their knowledge to us?


As to the point above, ecology is a complicated business and neither of those posts above will be 'true' - it will be much more complicated than that.

Fair enough - but if both opinions are wrong what is the real answer? Try me, I might just understand it.


Science is of course necessary to validate observations and if you think not then you're onto a loser and risk looking silly. Casual observations may of course be representative of the true situation but just saying ' i saw it so that means my opinion is obviously true' will rightly carry no weight.

I don't recall saying or thinking anything of the sort, or even expressing an opinion on the matter.

In general terms of 'hunters v conservationists' for want of a better term, the vast majority of the science does seem to back the conservationist view. Most articles published in respected journals support these views as well. Very few people appear to working on opposing ideas, trying to prove the conservationist view point wrong. You can find several reasons for this if you wish but the long and short of it is that those points appear to hold little weight and therefore are not worth investigating as a long term study.

Thank you for your advice.


shan't be revisiting this one to post either.

That's a pity.

Anthony
 
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I don't read Anthony's comments as antagonistic Tim - he's right to suggest that just because something is "old news" to experts (self-proclaimed or otherwise), it doesn't make the issue any less worthy of debate among those of us who aren't as informed of the "facts" (facts?) of the matter.

Anthony seems to have spotted a clear contradiction in the "evidence" and is simply wondering how to explain it - which seems a reasonable thing to want to do...

It's just a shame that an issue that is clearly important to a lot of people should be dismissed as irrelevant and - by implication - not worthy of expert comment.
 
to understand ecology fully or anything else for that matter you have to study it deeply. It means a lot of time spent reading books and working hard.

debates like these cannot be resolved here. They can only be resolved with yourself. It would take several pages to address some of the points raised (such as the one used to illustrate this thread) Studies over a long time frame elucidate what is going on in the natural world and they can't be distilled into simple short truths or 'facts' that will 'win' or 'lose' arguments.

There are no short cuts - it took me a long time to educate myself in this area (3-4 years full time studying well into the evenings). It's the only way. As it is with anything.

I still read and research things avidly and am lucky to have friends working in the field who keep me abreast of developments. Trying to answer these huge issuse within these pages belies a lack of uderstanding of the nature of the issue. The facts are in every half decent university and most public libraries and several websites, all we have to do is access them.
 
Another thread of deliberately obtuse cod-science. Having tried all the other debates we're now left with the old Magpie/songbird argument.

Now I know there will be some people out there who will know nothing of this, but to those of us who have heard the same old tired arguments trotted out time and time again ...

It has been proved time and time again that Magpie density does not affect the number of songbirds which survive to the the following year. Yes, they eat songbirds, but they are the birds that would have died anyway - if very Great Tit chick survived the winter we'd be swamped in the things by now.

As Time said, Ecology is far more complicated than just saying more Magpies, less songbirds, problem solved. THere is a correaltion between pig iron production in the US and the birth rate in the UK but they're not linked either.

Anyway, its not the Magpies its the Sparrowhawks. I know because Jeremy Clarkson said so on Have I got News For You and he must know!!
 
What happened to the bye bye Tim? :bounce:

Let's face it, almost any so-called 'fact' can be shown either true or not true by selective use of 'evidence'. In many cases, I don't think posters are trying to deceive anyone, but are reporting as they see the actuality. And since we come from such a wide background, we of course see things a bit different. I'd say just because someone suggests something as a fact, doesn't mean we should go for his/her throat if we think the fact is wrong. Present your own version of the same fact and someone, somewhere, might just get a bit of education.

PS it is of course a fact that magpies don't dent songbird populations, that one is a fact - all you posters who think otherwise are just wrong ;)
 
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Tim,

I don't wish to speak for Anthony, but I don't get the impression that he was trying to get to the bottom of anything - he is just flagging up a discrepancy which by definition underlines the fact that there's more to this than the simplistic conclusion that less magpies = more songbirds (maybe with the intention of making that very point?)

Mike,

this isn't "another thread of deliberately obtuse cod-science" - it hasn't had the chance to be: so far it's been little more than people whinging about cod-science!

;) ;) ;)

(Please note smileys!!)
 
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blythkeith said:
Tim,

I don't wish to speak for Anthony, but I don't get the impression that he was trying to get to the bottom of anything - he is just flagging up a discrepancy which by definition underlines the fact that there's more to this than the simplistic conclusion that less magpies = more songbirds (maybe with the intention of making that very point?)

QUOTE]

we have hit rock bottom and are asking for a shovel with the magpie v songbird debate. It was over long ago, as Jos and Mike have stated. You can choose not to believe it, as people choose not to believe many things, such as evolution etc. You could also make a semi-coherent case that could persuade people who are not aware of the facts that magpies do indeed affect songbird popluations. Unfortunately it is just not true.....not that this will be the end of it of course.

and Anthony's quote of Ian Peter's post doesn't make any sense to me at all. I'm baffled as to the meaning of it, and if read at face value it seems irrelevant and not related to Stevie Evens post at all. To have any effect on numbers it is necessary to remove all predators is so odd I wouldn't know where to start in repying!!!
 
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....people choose not to believe many things, such as evolution etc.

Woah there Tim!
Darwinian Evolution is VERY much under scrutiny at the mo! (viz the case of the Sticky Squid! A Darwinian impossibility!) You'd've been better using The Moon Landings as an example! LOL!
 
never mentioned Darwin David!

just evolution

...see how easy it is to get distracted from the 'issue'? ;)

P.S. Val K. passed on your regards yesterday; no sign of the gull (I go past too late!)
 
Tim Allwood said:
to understand ecology fully or anything else for that matter you have to study it deeply. It means a lot of time spent reading books and working hard.

debates like these cannot be resolved here. They can only be resolved with yourself. It would take several pages to address some of the points raised (such as the one used to illustrate this thread) Studies over a long time frame elucidate what is going on in the natural world and they can't be distilled into simple short truths or 'facts' that will 'win' or 'lose' arguments.

There are no short cuts - it took me a long time to educate myself in this area (3-4 years full time studying well into the evenings). It's the only way. As it is with anything.

I still read and research things avidly and am lucky to have friends working in the field who keep me abreast of developments. Trying to answer these huge issuse within these pages belies a lack of uderstanding of the nature of the issue. The facts are in every half decent university and most public libraries and several websites, all we have to do is access them.

I'll have to agree.Ecology is a really really complicated matter.Loads of studying(think I should get on with mine.It's not going to finish on its own.Darn!!!I hate time(and uni sometimes).Hey Tim!Got any good books to suggest to a university student studying geography and ecologie?Any suggestions would be really appresciated.

Thanks
Dimitris.
 
Ecology by Krebs is an old standard
Ecology by Begon, Harper and Townsend likewise

Evolution by Peter Skelton touches on similar areas but is excellent in its own right

An introduction to behavioural ecology by Krebs and Davies is very good as well
 
Tim Allwood said:
Ecology by Krebs is an old standard
Ecology by Begon, Harper and Townsend likewise

Evolution by Peter Skelton touches on similar areas but is excellent in its own right

An introduction to behavioural ecology by Krebs and Davies is very good as well


Ah the memories :)
 
if you know better Malky, write a paper, get it published, and put the rest of us right.

until then the accepted science is as Mike P and Jos pointed out.

best
Tim
 
alcedo.atthis said:

Following your line of discussion, why then does certain conservationists shout so loud about some so called rogue keepers shooting Hen-harriers.

If you base the same argument as in relationship between the Magpie and the keeper, both being the predator, to the songbird and the Hen-harrier respectively, then you contradict your own argument.
Pehaps its because we aren't completely tied into the predator/prey relationship. We don't suffer a decline in gamekeepers if there is a decline in Hen-harriers. We don't have a fall in population if there is a a fall on the Capercaille population. Whilst there is undoubtedly a relationship between our ravages on the environment and our long term survival, the relationship is more complex than that of 'simple' predatation.
http://www.globalchange.umich.edu/globalchange1/current/lectures/predation/predation.html
 
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