Who To Believe? (3 Viewers)

[Nightranger]

My pleasure. If and when you have read it, perhaps you would be good enough to report back as to whether it supports the assertion of the 'Field', and whether you still consider things to be rather so ambiguous. I'd read it myself but I can't afford the subscription at the moment. There are abstracts from several other interesting papers on Thrush ecology there. In particular one which states (from memory) that the effects of predation are still unclear.

In addition I am unsure, from the abstract, of the precise meaning of 'spatial variation'.

Phil

Hi Phil,

I did read the paper from Anthony's original reference but Tim already anticipated any possible reply by pointing out that the paper referred to nesting success and not population declines. As I pointed out elsewhere on this thread, magpies mainly predate nests when they have young of their own. This actually coincides with the middle broods of thrushes and blackbirds and not early and late broods. Now it is very important to realise that no one is saying that early and late broods are not predated merely that they are not systematically removed. The paper was therefore legitimate in indicating that predation pressure is important when considered in the light of breeding success but it is not possible to apply the same datasets to population declines for the reasons I have given. Indeed, that requires a totally separate study and this is what one of the co-authors was involved in. In fact, I found the relevant paper almost immediately with the help of a colleage because the co-author came up on a library search straight away. Anthony is partly right, it could be applied to other species within reason so his interpretation is correct but the conclusion is that it is irrelevant in the light of population trends.

Anthony, if it well be helpful, have a look at the paper I quoted and you will notice that the methods are totally different because of the very different requirements of the studies.

Ian

 

[RecoveringScot]

Hi Phil,

I did read the paper from Anthony's original reference but Tim already anticipated any possible reply by pointing out that the paper referred to nesting success and not population declines. As I pointed out elsewhere on this thread, magpies mainly predate nests when they have young of their own. This actually coincides with the middle broods of thrushes and blackbirds and not early and late broods. Now it is very important to realise that no one is saying that early and late broods are not predated merely that they are not systematically removed. The paper was therefore legitimate in indicating that predation pressure is important when considered in the light of breeding success but it is not possible to apply the same datasets to population declines for the reasons I have given. Indeed, that requires a totally separate study and this is what one of the co-authors was involved in. In fact, I found the relevant paper almost immediately with the help of a colleage because the co-author came up on a library search straight away. Anthony is partly right, it could be applied to other species within reason so his interpretation is correct but the conclusion is that it is irrelevant in the light of population trends.

<snip>

Ian

Ian, what is the meaning of the word 'spatial' here? Is it literally down to measurements in feet and yards, or over a wider geographical area?

Does it refer to distances between actual songbird nests? Or between Corvid nests and songbird nests? Sorry to be so vague about this.

Phil

 

[Edward woodwood]

"Shooting out their nests implies standing on the ground and shooting upwards....

Shooting out of their nests would suggest standing in them."

Shooting at their nests would suggest that one is deliberately trying to destroy the nest, or anything in it.
Shooting out a hole in a wall implies, one's firearm is protruding through the wall, not making holes in said.

Regards as ever

Malky

afraid Jane is correct here
to shoot out would be interpreted as a phrasal verb (shoot out)
the gun protruding thru the hole in the wall would be the normal verb 'to shoot' followed by the preposition 'out of' So we have 'to shoot out of' somewhere or something...and 'to shoot out' as in to destroy something or create a hole in something.

small word 'of' - but very important

teacher knows best on this Malky

 

[Jane Turner]

Ian, what is the meaning of the word 'spatial' here? Is it literally down to measurements in feet and yards, or over a wider geographical area?

Does it refer to distances between actual songbird nests? Or between Corvid nests and songbird nests? Sorry to be so vague about this.

Phil

My assumption is ... and it may be incorrect, that spatial variation refers to different values... in this case breeding output, over area, correlated in this example to corvidae density...

 

[Jane Turner]

"Shooting out their nests implies standing on the ground and shooting upwards....

Shooting out of their nests would suggest standing in them."

Shooting at their nests would suggest that one is deliberately trying to destroy the nest, or anything in it.
Shooting out a hole in a wall implies, one's firearm is protruding through the wall, not making holes in said.

Regards as ever

Malky

Shall we just put this to bed and say shooting out nests , shooting up nest and shooting at nests are equally valid... Can't help thinking thre are several million more important things to worry about.

 

[Nightranger]

Ian, what is the meaning of the word 'spatial' here? Is it literally down to measurements in feet and yards, or over a wider geographical area?

Does it refer to distances between actual songbird nests? Or between Corvid nests and songbird nests? Sorry to be so vague about this.

Phil

Hi Phil,

I think Jane has mostly answered this but spatial is a non-standard term to reflect the fact that the environment is seldom uniform. For example, urban habitats often have a great deal of food resources for certain species yet nesting opportunities may be relatively rare (particularly for species that prefer mature trees). Spatial in wildlife contexts usually means distance between for the habitat in question where this value may be different for a seemingly similar environment. In this case, it is the distance between nests (or density) that is important because predation sometimes imparts a lower density than would be expected. Indeed, this was also the case for magpies breeding in an area with a population of goshawks as set out in Tim Birkhead's book. However, that is a slightly different example in that magpies have a single brood per year and the goshawks predate mature adult magpies so it only effects the spatial density of nests (simply put, the magpies are being taken out at a steady rate and the populations of both species are at equilibrium). If we apply this to magpies and thrushes then it is a useful indicator but it is not quite the same because it is the nesting phase that is at risk and then only one of three anyway.

Ian

 

[RecoveringScot]

My assumption is ... and it may be incorrect, that spatial variation refers to different values... in this case breeding output, over area, correlated in this example to corvidae density...

Ah, brain-hurting stuff. OK, thanks.

Phil

 

[StevieEvans]

Tim
Thats for putting us right on that point of grammer.
They were initially my words regarding the shooting & i knew it was correct, but not why.
Its very important not to gan off 1/2 cocked......
SE.

 

[RecoveringScot]

Hi Phil,

I think Jane has mostly answered this but spatial is a non-standard term to reflect the fact that the environment is seldom uniform. For example, urban habitats often have a great deal of food resources for certain species yet nesting opportunities may be relatively rare (particularly for species that prefer mature trees). Spatial in wildlife contexts usually means distance between for the habitat in question where this value may be different for a seemingly similar environment. In this case, it is the distance between nests (or density) that is important because predation sometimes imparts a lower density than would be expected. Indeed, this was also the case for magpies breeding in an area with a population of goshawks as set out in Tim Birkhead's book. However, that is a slightly different example in that magpies have a single brood per year and the goshawks predate mature adult magpies so it only effects the spatial density of nests (simply put, the magpies are being taken out at a steady rate and the populations of both species are at equilibrium). If we apply this to magpies and thrushes then it is a useful indicator but it is not quite the same because it is the nesting phase that is at risk and then only one of three anyway.

Ian

Thank you for that Ian. It would thus seem a good idea, where game stocks are not at issue, to introduce Goshawks to keep the Magpies under control.

How's about that for a leap of faith?

Phil

 

[walwyn]

"

"teacher knows best on this Malky"
Does he. Not according to the English language.

You are still wrong because you can't get that interpretation from the similar phrase "shooting out the tyres" here:
http://www.guardian.co.uk/indonesia/Story/0,2763,395310,00.html
http://observer.guardian.co.uk/iraq/story/0,12239,963143,00.html

 

[David Bryant]

Well I've rarely heard such cr*p shooting out of people's mouths! (Or from their keyboards!) Sometimes these threads just degenerate into pedantic semantics!

 

[Edward woodwood]

er Malky....

look at Stevie's comments above - he said the words and he agrees with me and Jane - that is what he meant. Did you not read his post before you replied?

give up mate

and i reckon you're busking with the seven dictionaries bit......

 

[StevieEvans]

(Yes, i quite agree David.)

Malky, what if i'd left the 'out' out of it....? (my phrase, not Janes )

Your argument is pretty petty to say the least!

You've turned a serious (if slightly off topic) point about the potential accidental destruction of a Schedule 1 breeding species into nothing more than a farce.
Shame that some folks seem to forget this site is dedicated to wild birds ......... & not for arguments, point scoring & winding folk up.

Disgruntled SE.

 

[StevieEvans]

Tim,
Where's the 'Ref' at, when the mans being played instead of the ball ?
Maybe there aren't enough yella cards bein' dished out...?
Anyway, I wonder what the Magnificent 7 are....
S.

 

[Andrew Rowlands]

There are definitely people here who aren't interested in reasoned debate/have their own agenda/are only hear to wind others up. There's no point in trying to reason with them and the sooner they are ignored, the sooner they'll go away.

Malky, ..... you've turned a serious (if slightly off topic) point about the potential accidental destruction of a Schedule 1 breeding species into nothing more than a farce.
Shame that some folks seem to forget this site is dedicated to wild birds ......... & not for arguments, point scoring & winding folk up.

The 'Ref' calls in from time to time; if in the meantime, anyone thinks that a poster is 'playing the man not the ball' - hit the 'report bad post' button or PM an online Mod; DON'T bother replying to it, it makes it easier to remove!

Malky, if you don't understand a Post, ask the Poster to explain it.

Back to the Topic...

Andy.

 

[Jane Turner]

The 'Ref' calls in from time to time; if in the meantime, anyone thinks that a poster is 'playing the man not the ball' - hit the 'report bad post' button or PM an online Mod; DON'T bother replying to it, it makes it easier to remove!
Andy.

There have been a few studs up challenges though . Not sure there is much more to say unless Anthony wants another 20 papers which cite habitat changes as the cause of Songbird declines.

 

[Nightranger]

Thank you for that Ian. It would thus seem a good idea, where game stocks are not at issue, to introduce Goshawks to keep the Magpies under control.

How's about that for a leap of faith?

Phil

Hi Phil,

Well the evidence suggests that would actually work but there are two things that probably argue against doing anything deliberate. Firstly, there probably is not enough undisturbed woodland to suit goshawks near to urban areas where magpie populations are densest. Secondly, the racing pigeon people would rightly (in this case) object to predators being deliberately introduced in their area. It is one thing to have peregrines and sparrowhawks coming into urban areas naturally but quite another to artificially introduce a species. To be honest, this form of natural control seldom works the way we expect anyway.

Ian