Lancs Eagle Owls (1 Viewer)

[DGRW]

Paul -

Some clear idea of what prey items these birds are actually taking (not what they are capable of taking - that way lies sensationalism) would go a long way towards deciding many Birders point of view regarding "appropriate action".

If it were found that, for example, scarce raptor or other species populations were threatend then I'm sure that many of us would modify our views.

I'm not aware that any such negative impact is so far evident though.

I'm glad that we've arrived back at a few simple common sense facts in this discussion, unquantifiable semantic suppositions regarding historical records and interpretations or lack of them are a distraction I'm afraid. The pro-control advocates are better off without such a subjective distraction, a few verified statistics provide a much firmer argument.

Let's assume then that the vast majority of UK EO's are subsequent to illegal/accidental/intentional release as the recorded stats indicate. Yes the Eagle Owl is a "top predator" but, what if it is clearly found that this bird has no more impact on local ecologies than Little Owl, Goshawk, Muntjack Deer or Red Necked Wallaby. If that were the case then surely any "appropriate action" that is taken would be either consequential to precedent or it would set precedent.

So what kind of precedent would we attempt to set?

Total native genetic purity?

Blimey, we really have our work cut out there.

Or where practicable; is it not possible to work to the same levels of compromise that have come about with other species, some of which are arguably far more blatently non-native than EO's but that still survive in the UK with few problems.

Of course, if we suspect a problem on a par with, for example, North American Mink or Signal Crayfish then an entirely different initiative would be appropriate.

I think the problem that many people have at the moment is that even if we accept that very, very few UK EO's might be natural vagrants, if no ecological disaster appears imminent based upon what we SEE of populations such as the Lancashire population, then how can drastic culling measures be legitimised for EO's but not for other similarly present species populations?

I suspect that many of us just feel that we should have a little more proof, either way, before a decision is irrevocably made. The Lancashire population, I would imagine, is a perfect subject for observation in this regard and time is still on our side provided that we do the neccessary field-work and analysis whilst the population is still at what appears to be a controllable level.

 

[lewis20126]

Before the reintroduction programme began there was genetic work done that established the Welsh Red Kites were just part of the overall European gene pool and not an island race in their own right. Significantly there was at least one record of recruitment from Europe (Germany I think) to the Welsh population before the reintro prog. So the "widening of the gene pool" was not thinning out of different genes from the rest of Europe.

John

Not sure I was suggesting an "island race" - merely some modest element of genetic variation between the Welsh birds and the continental ones. Perhaps there was none (I'd like a look at a summary of the original paper(s)) and there is very little genetic variation across the range?

Has anyone done any genetic work on our beloved Eagle Owls?

 

[Pugs]

A few facts on EO's diet during the breeding season:

(NOTE : NOT ALL ITEMS, JUST THOSE WHERE THERE SEEMS TO BE SOME CONCERN)

1: Mink, Stoat & Weasel - Total = 0.4% of all Prey Items
2: Pine Martin - Total = 0.03% of all Prey Items
3: Badger - Total = 0.00% of all Prey Items
4: Raccoon Dog - Total = 0.00% of all Prey Items
5: Fox - Total = 0.1% of all Prey Items
6: Domestic Cat - Total = 0.03% of all Prey Items
7: Roe Deer - Total = 0.05% of all Prey Items (a fawn!)
8: Sheep(LAMB) - Total = 0.05% of all Prey Items
9: Corvidae - Total = 3.3% of all Prey Items
10: Galliformes - Total = 3.1% of all Prey Items
11: Rats, Mice & Voles - Total = 61.3% of all Prey Items
12: Hares - Total = 2.7% of all Prey Items
13: Strigidae, Falconiformes - Total = 2.2% of all Prey Items
14: Other birds - Total = 35.8% of all Prey Items
15: Anatidae - Total = 8.7% of all Prey Items

A total of 17,615 items were recorded

There is nothing in there that concerns me and if I can find a comparison with both GE & WTE I will post.

 

[Pugs]

Ecological isolation mechanisms of European owls

1: Differences in Morphology
2: Biogeographical Distributions
3: Differences in habitat selection
4: Differences in nesting habitats
5: Differences in hunting methods
6: Differences in diet

This would also apply to any interactions in regards to owls and diurnal birds of prey

 

[Edward woodwood]

A few facts on EO's diet during the breeding season:


1: Mink, Stoat & Weasel - Total = 0.4% of all Prey Items
2: Pine Martin - Total = 0.03% of all Prey Items
3: Badger - Total = 0.00% of all Prey Items
4: Raccoon Dog - Total = 0.00% of all Prey Items
5: Fox - Total = 0.1% of all Prey Items
6: Domestic Cat - Total = 0.03% of all Prey Items
7: Roe Deer - Total = 0.05% of all Prey Items (a fawn!)
8: Sheep(LAMB) - Total = 0.05% of all Prey Items
9: Corvidae - Total = 3.3% of all Prey Items
10: Galliformes - Total = 3.1% of all Prey Items
11: Rats, Mice & Voles - Total = 61.3% of all Prey Items
12: Hares - Total = 2.7% of all Prey Items
13: Strigidae, Falconiformes - Total = 2.2% of all Prey Items
14: Other birds - Total = 35.8% of all Prey Items
15: Anatidae - Total = 8.7% of all Prey Items

A total of 17,615 items were recorded

There is nothing in there that concerns me and if I can find a comparison with both GE & WTE I will post.

you really need to let people know which publication the info is from

extensive and much more complete diet information had already been posted on this thread (from Brds of the Western Palearctic)

It is impossible to draw anything conclusive from such vague information

 

[GMS]

Well there seems to be general agreement that:-

A. It is possible that Eagle Owls could reach Britain naturally.
B. The majority of current records are down to escaped or released birds or their offspring.

I have posted previously saying that I feel natural colonisation is unlikely, and to be honest the more I think about it, the less likely it seems. BWP gives Tawny Owl as having a broadly similar dispersal range to Eagle Owl, and there are recorded sea crossings by Tawny Owls (but none for Eagle Owls). Yet Tawny Owls don’t occur in Ireland and have never colonised (SW Scotland to NE Ireland is actually shorter than the distance from Dover to Calais). If wild Eagle Owls do occur here the numbers are probably so low that natural colonisation won’t take place now or in the foreseeable future.

Agree with most of the above. However I don't think your comparison with Tawny Owl is particularly valid. Tawny Owl is the most common owl on the continent with a density much higher and range much wider than EO. So of course there is a much higher chance for sea crossings by TO. If EO had the same density and range the possibility of crossing would be equally high.

 

[Pugs]

you really need to let people know which publication the info is from

extensive and much more complete diet information had already been posted on this thread (from Brds of the Western Palearctic)

It is impossible to draw anything conclusive from such vague information

Well, unless I can't find it, I cannot see any more complete figures in this thread

Sources:

Mikkola
Randla
Suomalainen
Kivirikko
Sulkava
Marz
Gronlund & Mikkola
Huhtala
Lagerstrom
Willgohs
Olsson

Tim, what do you find disturbing in my above post, these figures are from years of research from people who specialise in Owl ecology or have studied Birds Of Prey, they are not from a 'general birders' bible!

Would you like me to hike up the figure to include

1: Cow - Total = 15% of all Prey Items
2; Strigidae, Falconiformes - Total = 85% of all Prey Items

Is that better in keeping with your opinion?

Now Tim, can you post prey percentages like I have please?

 

[Edward woodwood]

Well, unless I can't find it, I cannot see any more complete figures in this thread

Sources:

Mikkola
Randla
Suomalainen
Kivirikko
Sulkava
Marz
Gronlund & Mikkola
Huhtala
Lagerstrom
Willgohs
Olsson

Tim, what do you find disturbing in my above post, these figures are from years of research from people who specialise in Owl ecology or have studied Birds Of Prey, they are not from a 'general birders' bible!

Would you like me to hike up the figure to include

1: Cow - Total = 15% of all Prey Items
2; Strigidae, Falconiformes - Total = 85% of all Prey Items

Is that better in keeping with your opinion?

Now Tim, can you post prey percentages like I have please?

well, thanks for more info

they aren't sources though, they're a list of authors

you posted a list of % of a diet. With no more detail.

I have no 'opinion', if you read the thread. I think the situation should be monitored but i don't have a blinkered viewpoint that i put forward avoiding published research, as the vast majority do on here.

you question about me posting 'prey percentages like you have' is typical of many postings we get on this forum. % diet from where? One pair, One population, all eagles owls ever? when? in what habitat and in what situation, as a total of what? What do those data you posted 'mean'? They are as they stand, meaningless.

sorry, but i'm done

Tim

 

[Edward woodwood]

here's one:

'some' studies show 'some' Eagle Owls predate mostly on birds (Bocheński et al. 1993) with some studies finding 83% of diet (by weight) made up by avian prey (Everett 1977).

see the problem with selective data?

really done now, sorry...

Tim

 

[Pugs]

On prey...

At the end of the day all I am posting for, is to allow people to see that this is a two way conversation and that there may be some 'bias' here on this forum by regular posters. This may annoy a few people but I feel I need to also quote from well known sources.

There seems to be hysteria towards the Eagle Owl and prey. An Eagle Owl is no more a top predator than a Golden Eagle or White Tailed Eagle, both of which are more than capable of taking large prey (including Birds of Prey) and the local cat!

People don't like to hear the above but that is nature (just look at Springwatch and how upset the public were, on certain subjects!)

Yes it is relevant because the hysteria quoted for EO's could be quoted for both Eagle species too and has been in the past, hence the demise and persecution of many of our wonderful Eagles from our lands in past generations.

I don't want to go in to prey specifics because quite frankly it is irrelevant and detrimental not only to EO's but GE's and the WTE.

 

[Pugs]

here's one:

'some' studies show 'some' Eagle Owls predate mostly on birds (Bocheński et al. 1993) with some studies finding 83% of diet (by weight) made up by avian prey (Everett 1977).

see the problem with selective data?

really done now, sorry...

Tim

But Tim is that not true on all species in the world?

They are sources from Mikkola's 'Owls of Europe', sorry but I ain't writing down every single study and date/time

 

[Himalaya]

when i went to whitendale i remember one thing - there were hardly ant corvids anywhere near the eagle owl nest. a few ravens crossed at the top of the valley but neither them, nor any of the hen harriers or short eared owls had any intention of descending down into the valley. they kept very close th the ridge. one of the short-eared owls did descend but eventually crossed over the road from a considerable height. maybe it knew of the danger that lay and also the fact that we were there too. the eagle owl had seen it still and watched the s e owl fly over even though the s e owl was for sure well over 30 metres above us.

there was a curlew in that valley - i heard the calls. they seemed not very far from the eagle owl nest but who knows. obviously sound can be deceiving and the birds could be quite far.

te forest of bowland seems to have a very high density of birds but tht was lacking anywhere near the eagle owl nest - i had seen no other corvids except a few ravens. there were no carrion crows or magpies around.

 

[nirofo]

Well regardless of all the published or unpublished findings, I for one hope that the Eagle Owl is here to stay! I am not particularly worried whether the birds are natural or introduced, I find them a welcome addition to our already diminished and diminishing even further avian populations. The numbers of birds present or even the likely projected numbers will hardly influence our indigenous species to the extent that the alarmists and would be cullers would have us believe. Even in Europe and scandinavia where the birds are fairly widespread they are hardly in sufficient numbers to make a huge impact on the local wildlife.

nirofo.

 

[Gomphus]

As I have stated before I have no real entrenched view on this other than we get it right...I do believe in science however and proper study and results. Earlier Pocile suggested I would like to use the UK as an introduction experiment...I find that slightly insulting and felt I had to reply.
At risk of repeating myself, what I have been doing is advocating we do keep an eye on this and monitor the situation, then when we have the facts, do whatever it takes either way. We will not be overrun by these birds in say the three years it takes to get some results, they cannot be rising that fast in numbers surely?
Eradication of these birds will always prove difficult IMO, as has been stated there are loads of licences given out, and loads of Owls escaping all the time, they have been for years it seems. Indeed my other half heard tales of EO's breeding in Scotland well over twenty years ago and has always maintained they were there!
No one yet has answered my question....how many pairs are we talking about? What for instance is the population growth? If Owls have been in the Bowland area, as has been suggested to me, for over twenty years, have they bred before? Mortality etc must effect these birds as any other so how many young survive from each nest? Are they self sustaining? We are using the examples of two publicly known pairs to suggest they are widespread, now I live in a county with tonnes of habitat for EO's and indeed we have had at least one female in suitable habitat for a long while she even built nests, however to my knowledge she never found a mate.... asking around I have not come across any breeding records. There are several recent records of known escapes in towns and gardens but these birds seem reluctent to head off to the wild areas? I really do think we have time to monitor the situation before we reach "critical mass". In any of these cases we have to be careful to make sure we don't send out the wrong message to people that large birds of prey are in someway alien to this country...and dangerous, and its ok to kill them, thus giving open season to all louts with air rifles etc not to mention gamekeepers! There is no way the press wouldn't get hold of a tale like this...
A friend of mine works for the police and frequently deals with calls from the public concerning large birds of prey and has to explain that big birds do exist in the UK and reassure them they are in no danger from them (they are usually Buzzards!). This often comes as a surprise to people! The public is swayed by the often hysterical reporting of killer birds of prey on the loose, I recall I think, a Ferruginous Hawk, escaped round me and the press were warning it would attack children, eat dogs etc! People were scared of it and wanted it shot on sight as a result! Talking to some one later they were amazed to find Buzzards live locally and were asking if they should be shot as big birds of prey were dangerous....

Incidentally to those who say there is no folk law evidence etc of EO's in the UK, These big Owls are difficult to see and Owls were Owls to many, perhaps we should take a look into the Fortean World...I'm sure I've read about Owlmen etc in the ancient lore? Big Owls anyone? Indeed there are descriptions of Owlmen in modern times I've often wondered how many of this type of thing relates to big escaped Owls. People are often surprised by how big Owls get you know!

Right thats it I have no more energy for this argument, I feel sad that we can sit here and advocate the shooting of any birds on heresay evidence (so far) without any scientific back up, surely that makes us no better than say those who want to kill raptors because they kill the pretty songbirds in their gardens....or even racing pigeon fanciers who kill Peregrines cause they eat their prize birds (they at least have evidence from rings in nests to back 'em up)! Sad isn't it, we cannot let these type of people point at us and say "well you said it was alright when you killed Eagle Owls because you "heard" they kill other birds".
If EO's are indeed proved to be a menace to the UK's native inhabitants then you would have my heartfelt support in a cull same as I have given to the Ruddy Duck Cull, but only when the proof is there for all to see.

Cheers

 

[Edward woodwood]

On prey...

At the end of the day all I am posting for, is to allow people to see that this is a two way conversation and that there may be some 'bias' here on this forum by regular posters. This may annoy a few people but I feel I need to also quote from well known sources.

yes, but your post was biased. If it was intentional, then that's pretty bad form, if it's unintentional then i can accept you don't get the 'fair test' stuff we hammer into kids in science lesson these days. Either way, it needs commenting on.

You posted it highlighting the rats, mice and voles at 61% to give people the impression that Eagle Owls 'as a species' have this kind of diet. The reality is that Eagle Owls will prey on available food and in certain areas this can include other raptors (to a level far beyond their abundance can sustain), and a whole variety of other animals.

Myself and Poecile have already referenced studies showing the effect EO can have on other raptors etc (see above thread). Regardless of my 'position' on EO, that is a known fact and something that anybody involved in making decisions about these birds has to take on board.

Life's too big and things are going way too wrong in general for me to be exercised about these birds one way or the other. But i do get annoyed with some of the misleading stuff posted at times - intentional or not.

Tim

 

[ColinD]

...If EO's are indeed proved to be a menace to the UK's native inhabitants then you would have my heartfelt support in a cull same as I have given to the Ruddy Duck Cull, but only when the proof is there for all to see.

Cheers

But what proof do you need? A wiped out population of harriers? Would that be proof enough? Do we have to wait that long? I don't know if Eagle Owls could potentially wipe out harriers in Bowland, but what I do know is, in the majority of cases, an introduced species causes harm to native species, all over the World. Is that not a fact?

If these birds are escapes or deliberate releases, then they have no place in our countryside. We don't need years of research to produce scientific evidence about the food they eat. Surely it's simple. If they're escapes they shouldn't be here.

 

[Pugs]

yes, but your post was biased. If it was intentional, then that's pretty bad form, if it's unintentional then i can accept you don't get the 'fair test' stuff we hammer into kids in science lesson these days. Either way, it needs commenting on.

You posted it highlighting the rats, mice and voles at 61% to give people the impression that Eagle Owls 'as a species' have this kind of diet. The reality is that Eagle Owls will prey on available food and in certain areas this can include other raptors (to a level far beyond their abundance can sustain), and a whole variety of other animals.

Myself and Poecile have already referenced studies showing the effect EO can have on other raptors etc (see above thread). Regardless of my 'position' on EO, that is a known fact and something that anybody involved in making decisions about these birds has to take on board.

Life's too big and things are going way too wrong in general for me to be exercised about these birds one way or the other. But i do get annoyed with some of the misleading stuff posted at times - intentional or not.

Tim

Yeah, likewise Tim you are bias. Lets leave it at that shall we?

 

[Edward woodwood]

Yeah, likewise Tim you are bias. Lets leave it at that shall we?

well, how?

I don't have an opinion on 'keeping' them or 'eradicating' them so how am i 'bias'. Or biased i should say.

Just putting info out there to be discussed not ignored.

Tim

 

[Himalaya]

there are a lot of "if's" here. as much as i like the idea of eagle owls colonising our island ad in fact in a way stil inclined to believe natural vagrants do get here - i also do accept that these birds could be escapees or released birds and if they were ever proved to be then i would support their removal from the countryside - removal meaning removal and not a cull. however, the owls got here its not their fault. they are just animals and have the urge to survive like the rest of us. i would not want to see them killed.

if they eagle owls do have a devastating affect on the hen harrier population then i do believe they should be caught and released elsewhere - whether they or natural vagrants or falconers birds. eagle owls could probably survive elsewhere with ease. hen harriers are very dependent upon bowland within england. i know the rspb mentionned money potentially being wasted - they have a right to - no one wants to support a failing project. i am not that bothered if the eagle owl ate peregrines, goshawks or buzzards - they would probably re-colonise and compared to the hen harrier in england they are less threatened.

i know thats interference but everyday we interfere in the environment and i dont see why we should nt do it to stop a threatened species being eradicated.

 

[Himalaya]

there also needs to be a system checking who has what pets wise and then if animals are sold, exchanged etc a department needs to be notified - bit like the DVLA and cars. i think all birds should have some sort of tag or ring on to show it is an escapee. of course these tags/rings could be taken off if owners deliberately let them go but the owner should have to answer questions released to the disappearance of the bird. i don't know if they have a system like that already.

there also needs to be exact information given out about how many eagle owls are breeding in the uk and possibly which areas - of course vague areas mentionned as don't want the birds to receive unsavoury visitors