Brian Stone
A Stone chatting
What an bizarre approach. "I believe 'x', refuse to provide any hard evidence for it but expect everyone else to disprove it"!
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Lancs Eagle Owls (1 Viewer)
- Thread starter Farnboro John
- Start date
What an bizarre approach. "I believe 'x', refuse to provide any hard evidence for it but expect everyone else to disprove it"!
considering 2 different pairs have bred - one for almost 10 years - who knows what others are breeding - they should be addedd to the list. what else do these birds need to do to qualify?
if EO'S have been escpain for decades - why breed recently? What about other birds escaping - why dont they breed?
if EO'S have been escpain for decades - why breed recently? What about other birds escaping - why dont they breed?
wigwhammer
Member
Tim: Your response is an excellent example of the point I was trying to make. I think it is patently obvious that I was not trying to be scientific - I am no scientist and make no pretence to give scientific "evidence".
As for the cow, I read in the extract from in a previous post:
and subsequently:
As a scientist you will undoubtedly know that an adult S. mollissima (eider duck) will weigh somewhere between 2 and 3 kg. A fox weighs anything from 3 kg up to an absolute maximum of 7 kg, "normal" being probably around 5-6 kg. In the article there is no mention of sheep or cattle - not one word - which, considering that a fox (and there the operative word is "once") was worthy of a special mention, is somewhat surprising - note also the date of the fox report.
Considering an OE's body weight of perhaps 1900-2500 g (♂) to 2600-4000 g (♀) these are quite considerable feats.
Can you seriously suggest any hypothesis as to how such a bird could kill a cow weighing half a ton or more? Why not suggest they are man-eaters in order to have them exterminated - surely a human child would by comparison be easy prey?
It is the logical conclusion of your opinion that anything that finds its way over the Channel or the North Sea - or even across the Atlantic - should be eliminated in case it decides to settle down and by some fluke meets a partner and starts to breed. "We don't want any immigrants here, thank you very much".....
Is not preventing the natural spread - or indeed the further evolution - of species just as reprehensible as other form of messing about with nature? I see where you are coming from, but there's no need to be so uncompromising.
This is, to me at least, simple common sense.
As for the cow, I read in the extract from in a previous post:
and subsequently:
As a scientist you will undoubtedly know that an adult S. mollissima (eider duck) will weigh somewhere between 2 and 3 kg. A fox weighs anything from 3 kg up to an absolute maximum of 7 kg, "normal" being probably around 5-6 kg. In the article there is no mention of sheep or cattle - not one word - which, considering that a fox (and there the operative word is "once") was worthy of a special mention, is somewhat surprising - note also the date of the fox report.
Considering an OE's body weight of perhaps 1900-2500 g (♂) to 2600-4000 g (♀) these are quite considerable feats.
Can you seriously suggest any hypothesis as to how such a bird could kill a cow weighing half a ton or more? Why not suggest they are man-eaters in order to have them exterminated - surely a human child would by comparison be easy prey?
It is the logical conclusion of your opinion that anything that finds its way over the Channel or the North Sea - or even across the Atlantic - should be eliminated in case it decides to settle down and by some fluke meets a partner and starts to breed. "We don't want any immigrants here, thank you very much".....
Is not preventing the natural spread - or indeed the further evolution - of species just as reprehensible as other form of messing about with nature? I see where you are coming from, but there's no need to be so uncompromising.
This is, to me at least, simple common sense.
Farnboro John
Well-known member
I dunno about EOs but I remember watching a White-tailed Eagle fly through a herd of cows at low level on Sheppey and it caused a stampede. Now why would the cows charge off unless the WTE had already carried off one of them?!
John
You say that as a joke... but I think some of the more hysterical tabloids did report something along the lines of "giant owls capable of snatching small children" when the first reports hit the headlines!!!
A few thoughts numbered for ease of reference:-
1. I find the statement by the World Owl Trust very unconvincing because it fails to back its stance up with any supporting facts. For example they refer to fossil evidence and birds breeding before the Yorkshire pair, but as the RSPB statement notes “There is some limited fossil evidence of eagle owls in Britain, but this is almost entirely from before the last Ice Age, when clearly the climate and the habitat were very different and Britain was connected to the continent. Several other former breeding birds, such as cranes, appear in art and literature, yet despite its size and being considered a bird of ill omen elsewhere in Europe, eagle owls do not appear regularly in English or Celtic culture until relatively recently.” The World Owl Trust cite the fact that there were records/breeding birds before the Yorkshire pair which appeared on TV, but as the RSPB note Eagle Owls have been kept in captivity since at least the 17th century.
http://www.owls.org/News/eagle_owl.htm
http://www.rspb.org.uk/ourwork/policy/species/eagleowls.asp
2. Some people have said that they should be given the benefit of the doubt (ie if there’s no obvious evidence, such as jesses, that they’re escapees they should be treated as wild birds). However I would again refer you to the RSPB statement which notes that in a 5 year period there were over 2000 applications for licenses to keep Eagle Owls. From my limited knowledge of falconry I believe a ballpark figure of 25% of birds lost or released in the first year is possible. That gives a figure of 80 escaped or released Eagle Owls in Britain per year. Obviously that figure makes no allowance for unlicensed/unregistered owls, which is probably unquantifable, but could be significant.
3. Balance that figure of 80 escaped or released birds per year against the likelihood of wild birds occurring here. I would suggest that if wild birds are occurring, then the numbers will be very low (one or less per year). I base that suggestion on the fact that European Eagle Owls are not migratory or even particularly nomadic, and as the RSPB note “there are relatively few eagle owls in northern France, Belgium and the Netherlands and there is little evidence that eagle owls will cross open sea.” Note that the Hawk Owl which seems better suited to a sea crossing nevertheless finds the Baltic a significant barrier. With odds of 80/1 against I can’t see why an Eagle Owl not showing obvious signs of captivity should be assumed to be wild. After all if an owner who’s got fed up of their owl decided to release it back into the wild there is a very good chance that they will remove the jesses and transport it somewhere remote and away from their home.
4. The BOU carried out a survey of records in the 1990s and felt that in those cases where the identification was proven that the possibility of escapes or releases could not be eliminated. The simple fact is that there are no formally accepted records of wild Eagle Owls in this country in the same way as there are for say Hawk and Tengmalms Owls. On this thread and others about Eagle Owl people have cited Eagle Owls seen on North Sea oil rigs or in situations suggestive of natural vagrancy. If they have records like that then they really should submit them and ideally share brief details with us on Bird Forum. For example can anyone provide a link to details/photos of an Eagle Owl on a North Sea oil rig?
5. It may be that Eagle Owls are in the process of colonising Britain, but it’s my belief based on the figures detailed above that the process is almost entirely fuelled by released or escaped birds. I would welcome any evidence (as opposed to opinion and second-hand anecdote) which adds to the debate, but simply saying that they might be wild and should be given the benefit of the doubt isn’t a strong argument.
6. My reservations about introducing Eagle Owls into Britain is based on the fact that I thought we had learnt from past mistakes that introducing non-native species is not a good idea. It seems deeply flawed to discard that principle pretty much on the grounds that Eagle Owls are spectacular and attractive birds. It’s perfectly possible that introducing Eagle Owls would have very little effect overall on our native wildlife, but clearly we have no way of predicting that in advance.
7. If Eagle Owls colonise naturally then I would support them 100% (in the same way as say Little Egret and Cetti’s Warbler). That happens to be the opinion expressed in the RSPB statement (contrary to comments elsewhere that the RSPB are seeking to introduce Eagle Owls or, alternatively, to have them exterminated), but please note that my only link with the RSPB is as an ordinary member.
1. I find the statement by the World Owl Trust very unconvincing because it fails to back its stance up with any supporting facts. For example they refer to fossil evidence and birds breeding before the Yorkshire pair, but as the RSPB statement notes “There is some limited fossil evidence of eagle owls in Britain, but this is almost entirely from before the last Ice Age, when clearly the climate and the habitat were very different and Britain was connected to the continent. Several other former breeding birds, such as cranes, appear in art and literature, yet despite its size and being considered a bird of ill omen elsewhere in Europe, eagle owls do not appear regularly in English or Celtic culture until relatively recently.” The World Owl Trust cite the fact that there were records/breeding birds before the Yorkshire pair which appeared on TV, but as the RSPB note Eagle Owls have been kept in captivity since at least the 17th century.
http://www.owls.org/News/eagle_owl.htm
http://www.rspb.org.uk/ourwork/policy/species/eagleowls.asp
2. Some people have said that they should be given the benefit of the doubt (ie if there’s no obvious evidence, such as jesses, that they’re escapees they should be treated as wild birds). However I would again refer you to the RSPB statement which notes that in a 5 year period there were over 2000 applications for licenses to keep Eagle Owls. From my limited knowledge of falconry I believe a ballpark figure of 25% of birds lost or released in the first year is possible. That gives a figure of 80 escaped or released Eagle Owls in Britain per year. Obviously that figure makes no allowance for unlicensed/unregistered owls, which is probably unquantifable, but could be significant.
3. Balance that figure of 80 escaped or released birds per year against the likelihood of wild birds occurring here. I would suggest that if wild birds are occurring, then the numbers will be very low (one or less per year). I base that suggestion on the fact that European Eagle Owls are not migratory or even particularly nomadic, and as the RSPB note “there are relatively few eagle owls in northern France, Belgium and the Netherlands and there is little evidence that eagle owls will cross open sea.” Note that the Hawk Owl which seems better suited to a sea crossing nevertheless finds the Baltic a significant barrier. With odds of 80/1 against I can’t see why an Eagle Owl not showing obvious signs of captivity should be assumed to be wild. After all if an owner who’s got fed up of their owl decided to release it back into the wild there is a very good chance that they will remove the jesses and transport it somewhere remote and away from their home.
4. The BOU carried out a survey of records in the 1990s and felt that in those cases where the identification was proven that the possibility of escapes or releases could not be eliminated. The simple fact is that there are no formally accepted records of wild Eagle Owls in this country in the same way as there are for say Hawk and Tengmalms Owls. On this thread and others about Eagle Owl people have cited Eagle Owls seen on North Sea oil rigs or in situations suggestive of natural vagrancy. If they have records like that then they really should submit them and ideally share brief details with us on Bird Forum. For example can anyone provide a link to details/photos of an Eagle Owl on a North Sea oil rig?
5. It may be that Eagle Owls are in the process of colonising Britain, but it’s my belief based on the figures detailed above that the process is almost entirely fuelled by released or escaped birds. I would welcome any evidence (as opposed to opinion and second-hand anecdote) which adds to the debate, but simply saying that they might be wild and should be given the benefit of the doubt isn’t a strong argument.
6. My reservations about introducing Eagle Owls into Britain is based on the fact that I thought we had learnt from past mistakes that introducing non-native species is not a good idea. It seems deeply flawed to discard that principle pretty much on the grounds that Eagle Owls are spectacular and attractive birds. It’s perfectly possible that introducing Eagle Owls would have very little effect overall on our native wildlife, but clearly we have no way of predicting that in advance.
7. If Eagle Owls colonise naturally then I would support them 100% (in the same way as say Little Egret and Cetti’s Warbler). That happens to be the opinion expressed in the RSPB statement (contrary to comments elsewhere that the RSPB are seeking to introduce Eagle Owls or, alternatively, to have them exterminated), but please note that my only link with the RSPB is as an ordinary member.
Farnboro John
Well-known member
Many thanks for the response John which I will try to answer.
I can’t agree that “almost entirely” means the same as “not entirely”, but I see no point for either of us in getting into a pedantic argument about words. However it would be helpful if someone could point out references to fossil records of Eagle Owl in Britain since the last Ice Age (I’ll happily admit it’s not my area of expertise). Indeed any pointers to references in British folklore etc which refer to Eagle Owls would also move things along.
I don’t think the gamekeepers in the Peak District and elsewhere give the slightest thought to the Eagle Owl situation when they go persecuting Goshawks. I’m certainly not advocating the elimination of Eagle Owls, but there is an obvious difference from Goshawks in that our natural population of Goshawks was eliminated relatively recently and has only just recolonised; whereas Eagle Owls either haven’t had a natural population here since the last Ice Age or haven’t had a natural population here for hundreds of years depending on your point of view.
I didn’t compare Eagle Owls with Long-eared and Short-eared Owls, not in an attempt to be “blatantly selective”, but for the precise reason that there is an established, normal pattern of migrational sea crossings in Long-eared and Short-eared Owls, whereas there is no such pattern in Eagle Owl. If you have evidence of sea crossings by Eagle Owls that would move the discussion forward.
There are similarities in shape between Eagle and Long-eared and Short-eared Owls, but I suspect that the significantly broader wings of the Eagle Owl would be a disadvantage on a sea crossing. Someone with a good understanding of bird flight might be able to comment on wing loading and aspect ratio etc, but I can’t.
I did mention Hawk Owl as being more suited to a sea crossing for the following reasons:-
A. Narrower wings (hawks are better at sea crossings than eagles).
B. Much more nomadic lifestyle, routinely travelling much further than Eagle Owls and prone to irruptive movements at irregular intervals.
C. The longest recorded movement for a Hawk Owl is over 4 times that for an Eagle Owl (and I suspect the sample size for Hawk Owl is much smaller).
D. Although the Baltic is a significant barrier to them, they have crossed it to reach Denmark and France, indeed the large movement in 1983/4 produced about 200 in Denmark and one even reached the Faeroe Islands.
E. There are four European records (in Britain and the Canaries) of the N American race of Hawk Owl. I guess it’s just possible that they travelled the whole way on a ship, but it’s far more likely that they flew part, most or all of the way.
I didn’t mention dispersal in Eagle Owls because (bearing in mind that they don’t migrate) it would be extremely surprising if they didn’t disperse. BWP quotes Norwegian studies as saying that young don’t leave the natal area until August/September and there is a tendancy for them to disperse towards the coast.
It’s not hard to imagine a released or escaped bird or one of the young from an unlocated pair somewhere in Britain reaching a coastal migration point in October and being hailed by some as “probably” or “almost certainly” a natural migrant.
Looking at the facts I think a natural colonisation by Eagle Owls is extremely unlikely, but conditions change and who knows what the situation will be further down the line? Certainly more information is always welcome, and ringing recoveries which provide evidence of sea crossings by Eagle Owls would be very interesting.
I can’t agree that “almost entirely” means the same as “not entirely”, but I see no point for either of us in getting into a pedantic argument about words. However it would be helpful if someone could point out references to fossil records of Eagle Owl in Britain since the last Ice Age (I’ll happily admit it’s not my area of expertise). Indeed any pointers to references in British folklore etc which refer to Eagle Owls would also move things along.
I don’t think the gamekeepers in the Peak District and elsewhere give the slightest thought to the Eagle Owl situation when they go persecuting Goshawks. I’m certainly not advocating the elimination of Eagle Owls, but there is an obvious difference from Goshawks in that our natural population of Goshawks was eliminated relatively recently and has only just recolonised; whereas Eagle Owls either haven’t had a natural population here since the last Ice Age or haven’t had a natural population here for hundreds of years depending on your point of view.
I didn’t compare Eagle Owls with Long-eared and Short-eared Owls, not in an attempt to be “blatantly selective”, but for the precise reason that there is an established, normal pattern of migrational sea crossings in Long-eared and Short-eared Owls, whereas there is no such pattern in Eagle Owl. If you have evidence of sea crossings by Eagle Owls that would move the discussion forward.
There are similarities in shape between Eagle and Long-eared and Short-eared Owls, but I suspect that the significantly broader wings of the Eagle Owl would be a disadvantage on a sea crossing. Someone with a good understanding of bird flight might be able to comment on wing loading and aspect ratio etc, but I can’t.
I did mention Hawk Owl as being more suited to a sea crossing for the following reasons:-
A. Narrower wings (hawks are better at sea crossings than eagles).
B. Much more nomadic lifestyle, routinely travelling much further than Eagle Owls and prone to irruptive movements at irregular intervals.
C. The longest recorded movement for a Hawk Owl is over 4 times that for an Eagle Owl (and I suspect the sample size for Hawk Owl is much smaller).
D. Although the Baltic is a significant barrier to them, they have crossed it to reach Denmark and France, indeed the large movement in 1983/4 produced about 200 in Denmark and one even reached the Faeroe Islands.
E. There are four European records (in Britain and the Canaries) of the N American race of Hawk Owl. I guess it’s just possible that they travelled the whole way on a ship, but it’s far more likely that they flew part, most or all of the way.
I didn’t mention dispersal in Eagle Owls because (bearing in mind that they don’t migrate) it would be extremely surprising if they didn’t disperse. BWP quotes Norwegian studies as saying that young don’t leave the natal area until August/September and there is a tendancy for them to disperse towards the coast.
It’s not hard to imagine a released or escaped bird or one of the young from an unlocated pair somewhere in Britain reaching a coastal migration point in October and being hailed by some as “probably” or “almost certainly” a natural migrant.
Looking at the facts I think a natural colonisation by Eagle Owls is extremely unlikely, but conditions change and who knows what the situation will be further down the line? Certainly more information is always welcome, and ringing recoveries which provide evidence of sea crossings by Eagle Owls would be very interesting.
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i think neither point of view can be fully validified. i do think its strange why only a few have managed to breed and how one of the young has dispersed to shropshire only to be killed yet some say they are not nomadic.
the fact that people have let eagle owls go in the country is clouding and biasing the argument. we are tarring all eagle owls with the same brush. surely if they were an escape they could have stayed somewhere residential?
the fact that people have let eagle owls go in the country is clouding and biasing the argument. we are tarring all eagle owls with the same brush. surely if they were an escape they could have stayed somewhere residential?
bitterntwisted
Graham Howard Shortt
Like the Goshawks?
All the evidence painstaking presented by several knowledgeable posters throughout this and previous threads suggests that the Eagle Owls at large in this country are escapes or descendants of escapes. No credible evidence of natural colonisation has been provided. Why is that so hard for people to accept?
Graham
wigwhammer
Member
I know this goes off on a rather different tack and I won’t persue the matter further, but wouldn’t it be equally useful to be campaigning for much more restrictive regulations on keeping wild birds (or any wild animals)?
I know that here in Germany (ok – everything is highly regulated here, but sometimes it’s not just pure bureaucracy) it is illegal to keep any kind of wild creature (including imports) without a licence – and to get a licence is virtually impossible.
People who keep BOP for hawking etc. have special, but no less strict regulations. They must be trained, certified and registered hunters with a special hawking licence. They must have an aviary built to strict standards, they have to have a “dedicated” freezer for storing food (mice, rats etc) and so on and on top of that they are subject to regular on-the-spot inspection by the authorities.
Of course, all birds are marked and registered, so there’s no chance of getting away with just setting one free.
It's unthinkable here that anybody could have a pet owl and I must say that I am quite horrified that this seems to be the case "back home".
I know that here in Germany (ok – everything is highly regulated here, but sometimes it’s not just pure bureaucracy) it is illegal to keep any kind of wild creature (including imports) without a licence – and to get a licence is virtually impossible.
People who keep BOP for hawking etc. have special, but no less strict regulations. They must be trained, certified and registered hunters with a special hawking licence. They must have an aviary built to strict standards, they have to have a “dedicated” freezer for storing food (mice, rats etc) and so on and on top of that they are subject to regular on-the-spot inspection by the authorities.
Of course, all birds are marked and registered, so there’s no chance of getting away with just setting one free.
It's unthinkable here that anybody could have a pet owl and I must say that I am quite horrified that this seems to be the case "back home".
I don't think anyone finds it hard to accept that there is no evidence, because there isn't!
The question is - why is it so hard for some people to accept that natural colonisation may have happened even though there is no evidence for it?
Its the arrogance of some people who refuse to accept that they don't know everything, that is hard to accept - and why this debate is going on and on!
Edward woodwood
Member
DGRW
Well-known member
Old cliche -
"absence of evidence is not evidence of absence"
I therefore have to agree with Amarillo i.e. that some birds may have colonised naturally but also that some are obviously escapes or descendants of escapes. We just don't know as a certainty.....do we?
I have to say that I personally find it quite likely that northern European Birds might find their way naturally to the UK. It wouldn't be particularly unusual in terms of many of the other incidentals that we find in the UK every year would it?
I'm not in favour of any kind of "ethnic cleansing" for the sake of it but at the same time I have to accept that some species simply cannot fit in to modern UK ecologies without causing some level of degradation to those ecologies (e.g. North American Mink).
There's also a side to me that would like to think that EO's could exist within modern UK ecologies without degrading them and that they would be a fantastic addition to the British A List.
So what exactly IS the hard evidence?
Is it demostrated that EO's are damaging to UK ecologies or is it a matter of conjecture? If it's a matter of conjecture then just how valid is that conjecture?
I got talking to an old chap in a hide a couple of weeks ago who started telling me about his Lancashire Eagle Owls. He finished by saying, and I quote:
'Bloody RSPB, what do they know, bloody boffins in suits'
I decided to not pursue the discussion further at that point but I was more than a little amused as one of the boffins in question was sitting at the other end of the hide listening in on the conversation. He decided to let it lie as well.
Is it proven that EO's are a problem?
If not; what studies are in place? what are those studies appearing to show?
Do we have any hard evidence or do we have (admittedly/arguably) valid conjecture?
Would EO predation be more damaging than, for example, White Tailed Eagle predation?
There seem to be many that are really getting their knickers in a twist over Eagle Owls, are they really that significant a predator or problem?
"absence of evidence is not evidence of absence"
I therefore have to agree with Amarillo i.e. that some birds may have colonised naturally but also that some are obviously escapes or descendants of escapes. We just don't know as a certainty.....do we?
I have to say that I personally find it quite likely that northern European Birds might find their way naturally to the UK. It wouldn't be particularly unusual in terms of many of the other incidentals that we find in the UK every year would it?
I'm not in favour of any kind of "ethnic cleansing" for the sake of it but at the same time I have to accept that some species simply cannot fit in to modern UK ecologies without causing some level of degradation to those ecologies (e.g. North American Mink).
There's also a side to me that would like to think that EO's could exist within modern UK ecologies without degrading them and that they would be a fantastic addition to the British A List.
So what exactly IS the hard evidence?
Is it demostrated that EO's are damaging to UK ecologies or is it a matter of conjecture? If it's a matter of conjecture then just how valid is that conjecture?
I got talking to an old chap in a hide a couple of weeks ago who started telling me about his Lancashire Eagle Owls. He finished by saying, and I quote:
'Bloody RSPB, what do they know, bloody boffins in suits'
I decided to not pursue the discussion further at that point but I was more than a little amused as one of the boffins in question was sitting at the other end of the hide listening in on the conversation. He decided to let it lie as well.
Is it proven that EO's are a problem?
If not; what studies are in place? what are those studies appearing to show?
Do we have any hard evidence or do we have (admittedly/arguably) valid conjecture?
Would EO predation be more damaging than, for example, White Tailed Eagle predation?
There seem to be many that are really getting their knickers in a twist over Eagle Owls, are they really that significant a predator or problem?
Jos Stratford
Beast from the East
Try a comparison with Snowy Owl, a far closer match to an Eagle Owl than a Hawk Owl. And Snowies obviously do cross water.
Hawk Owls are, by and large, much easier to see than Eagle Owls - so recorded movements is not that comparable between them.
wigwhammer
Member
There seems mainly to be speculation based on hearsay - and of course Tim thumping his bible, apoplectic at the thought of anybody doubting his Truth.....
Yes, Tim, now you come to mention it I do have some vague memory from way back that there are differently sized cattle - and that they have babies too. Thank you for preventing me from having to go to my grave in ignorance.
But I'm sorry, your roaring fails to convince me - perhaps you could post the relevant passage from the BWP (unedited if you please) and tell us from which edition you are quoting.
As I already pointed out, the extract from BWPi posted earlier in this thread makes no mention of it and I would tend to assume that the BWPi is more up-to-date than your £30 edition (c/f what I believe to be around £1100 retail price). The BWPi does certainly claim to contain "The entire text of The Handbook of the Birds of Europe, North Africa and the Middle East (the complete 9-volume set, known as BWP)" updated for 2006
KnockerNorton
Well-known member
KnockerNorton
Well-known member
Indeed they do, and have reached Uk in some numbers. Even bred several times. Would we consider them a native British bird and a coloniser though? No, we wouldn't, they're sporadic vagrants. Despite a fair bit of apparent habitat for them. And even if EO has reached UK at all (which a couple may have), we can be fairly sure that it's been in nothing like the numbers that Snowy Owls have. So that helps us get this in perspective. There's a damn lot of EO about for such a (possible) rare vagrant...many many more than more the regular Snowy Owl could lead us to expect - and they haven't even colonised yet.
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