Eurasian Eagle Owl – Update.
We have enclosed a claim made in the Collins Bird Guide, first edition (1999) and repeated again in the new updated second edition published January 2010.
“Only a hand full of genuine records in Britain, all in the 19th Century.”
Collins Bird Guide, described as the user Bible for dedicated birders both the UK and across Europe. The first edition sold a quarter of a million copies, and the claim made in that edition has been re-stated once again in the new updated second edition.
This must now provide some room for doubt. Why was this claim never questioned previously?
Eagle Owls Forest of Bowland: Historical Update.
Due to the lack of public knowledge relating the eagle owls in Bowland, and what has been happening since 2006, follow the link below for further information:
An earlier post stated the Bowland owls had not taken any hen harriers. I am not aware of any serious attempt to monitor their diet, but ad hoc searches of the owl’s nesting area revealed 2-3 dead harriers in 2007. One of the birds was an adult (BTO ring) and feathers of 1+ juvenile harrier(s) were also found. Given the limited effort involved it would not be an unreasonalbe assumption that the actual numbers of harriers taken could be greater. Incidentally, these harrier feathers are separate to the feathers of a common gull also found at the same site.
This is a very interesting debate. Whilst eagle owls have not caused the extinction of any other raptor species elsewhere within their range, and any pouplation level impact on other raptor / prey species in the UK seems highly unlikely, a localised impact cannot be ruled out. Whilst it is not possible to say for certain whether eagle owls could impact Bowland’s harriers (or vice versa), if you are advocating the presence of eagle owls in Bowland you are taking a risk with the last stronghold of hen harriers in England and an area with the highest level of protection possible.
The level of risk is unquantified and some people will argue it is minimal (up to 3 dead birds in one year suggests not), but nobody can give a guarantee (despite some of the definitive comments left on this site). Some people might think the presence of eagle owls is a risk worth taking – other people might be more precautionary. Personally, like many of the contributors to raptor politics I think the eagle owls are incredible birds, but if anything else was proven to be killing multiple harriers in Bowland in a single year would we not be a little more objective?
Your comments are only partly accurate; the remains of the dead harrier with a BTO ring was recovered close to the abandoned 2007 eagle owl nest on the 27th July after the 3 chicks had fledged. However, no conclusive evidence that an eagle owl had killed this bird was established. In the same region in 2007 there were both peregrine and goshawk, either of these two species could have been responsible. The detail and circumstances were viewed to be very suspicious by the RSPB and local experts, who jointly believed the corpse, already dead, may have been planted close to the nest to give the eagle owl a bad name.
Regarding the second dead harrier chick, this was found close to an active nest after fledging on the moor just above the eagle owl territory on 1st August. The dead chick had died from natural causes but eventually had been eaten by the remaining sibling. Had an eagle owl been involved all the chicks would have been killed and eaten, not just a single bird.
Last year there 10 breeding attempts made by hen harriers in Bowland of which 4 nests were successful; three nests fledged 5 young on moorland owned by United Utililities, an additional single nest located at Marshaw owned by the Duke of Westminster fledged an additional 5 chicks. The 6 nests which failed in 2009, including the nest containing the 3 dead chicks were all located on moorland owned by United Utilities. You can work out the percentage failure rate of nests sites yourself. The proved threat to hen harriers locally in Bowland is not from the eagle owl we can assure you; the figures may give you a clue to who might be responsible. If you still have doubts, read the details already published in the Raptor Politics web site.
Hi Admin,
If my comments are only partially accurate I welcome their correction with facts, but not with misinformation.
It is accepted practice that prey remains and pellets found at or near a raptor nest are used for dietary analysis. It is not possible to tell whether an item has been scavenged or predated without a detailed post mortem of a carcass, but a dead harrier found next to an eagle owl nest amongst other prey remains is likely to have been predated. I can’t rule out some conspiracty theory that somebody would risk impisonment and place the body of harrier near the eagle owl nest, but to me this seems highly unlikely and there is no evidence of this.
What proof do you have to make any claim that the corpse of the adult harrier was already dead before it arrived at the eagle owl nest? In order to do this you must have proof the harrier was not predated, but either scavenged or planted (having been killed some other way). If you have the results of the Post Mortem that prove the time and cause of death of this adult harrier please post them on the site…
Feathers of the juvneile harrier(s) were found next to the eagle owl nest. They were not recovered from an active harrier nest and there was no carcass. Regardless of where they were found, it is not possible to conclude from a pile of feathers that this was a chick that died of natural causes and was eaten by its siblings (with its feathers subsequently transported by unknown means away from the harrier nest to the eagle owl nest).
If anyone had suggested the resident nesting adult female harrier was taken by the eagle owl, then I agree with you that there is no evidence of this, but this could not have been confirmed by radio-tracking. Batteries on radio (as opposed to solar powered satellite transmitters) do not last long enough to allow tracking of on an adult bird.
I am fully aware of the breeding figures published on the raptor politics website for harriers in Bowland and the conclusions that have been drawn. In recent years (the last five or so), there has not been a single proven case of hen harreir persecution in Bowland. I know there was plenty before this. I am not stating persecution does not occur, but the evidence you dismiss that harriers might have been taken by eagle owls is far stronger than any evidence that harriers have been killed by man over this time period in Bowland.
Clearly the harrier population in England is limited by perseuction and no doubt some of the harriers dispersing away from Bowland meet a sad and premature end. However, with so much available unoccupied habitat, the loss of any harriers is likely to be additive to other causes. Whilst the loss of a harrier thorugh illegal perseution makes the blood boil, in terms of effect on the Bowland harrier population it doesn’t make any difference how a harrier was killed. Neither persecution or predation should be dismissed.
I really enjoy the website but personally I think some of the good causes you are fighting for would be better served if the arguemnts were a little more balanced.
We appreciate your comments, we wish that more people like you with a different perspective would post messages but dissapontingl very few do. Our replies to your original post were based upon first hand detail we had been given, and yes you are correct some of the assumptions are just that. However we are able to confirm that the feathers collected close to the 2007 eagle owl nest, were in fact proved to have been from a common gull- there is no doubts about that.
Regarding the banded hen harrier corpse found in 2007, we will never know the truth one way or the other. Anyone can make assumptions, but that’s all they will ever be under such circumstances. The only way to prove one way or another if harriers or any other species of birds are being predated by eagle owls will be to observe such behaviour. Or as you so rightly point out from the remains in pellets.
Your last point, persecution has always been almost impossible to prove without an eye witness. The regions we are talking about are remote to say the least. The failure rate for all game predating raptor species in Bowland throughout the last 40 years speaks for itself. When field workers visit nest after nest where the eggs, young and adult birds have simply vanished or have been found dead year after year, there can only really be one valid conclusion.
Here are my ‘way off the mark assumptions’:
i) Way off the mark assuption number 1: Harrier remains found near an eagle owl nest could be the result of intra-guild predation (I said 2+ but De Facto actually said 3).
ii) Way off the mark assumption number 2: Any losses of hen harriers are of concern, regardless of specific mortality factors.
Here are your comments which apparently demonstrate my points are way off the mark:
i) De-facto’s facts: A dead hen harrier chick found at the nearest harrier nest to the owls died of natural causes.
Perhaps other people have incorrectly suggested this dead chick was taken by the owls, but not me. I agree with your comments but have never referred to this breeding attempt / these birds. You have jumped to the conclusion that I am talking about this harrier nest for some reason but a dead harrier chick at a harrier nest is totally separate to harrier remains found at the owls’ nest.
ii) De-facto’s facts: ‘The only reasonable assumption’ for finding a dead harrier near the owls’ nest is that it was planted as the birds were a few hundred metres away at this stage.
So it is possible for this website to simultaneously promote the eagle owl’s dispersal ability over hundreds of kilometres across large water bodies, yet it would be unreasonable to assume one of the birds might have flown less than a few hundred metres? Were the other prey premains near the harrier remains also planted?
iii) De-facto’s facts: The adult female harrier (from the nest I have never mentioned) was tracked by satellite away from Bowland.
There were no adult hen harriers being satellite tracked in England in 2007 (I have made a phone call to confirm this). This is a physical impossibility. There is no evidence to suggest the adult female was taken, but it is worrying that such misinformatoin is being used when having a rational discussion about Bowland’s harriers (see my earlier comments about objectivity).
Thank you very much for your many comments, your contribution has been welcomed, providing refreshing impetus to this on-going debate.
We at raptor politics always do our very best to be factual, but if a mistake is made then we will always be prepared to hold up our hands. As you will appreciate, the majority of our posted comments are received from a wide readership, which must be taken on trust.
We have now amended the error regarding the use of telemetry at the harrier nest located above and close to the eagle owl nest in 2007. The brown female harrier had not been fitted with such a device.
The information relating to telemetry, should have referred to a second female, fitted with telemetry as a nestling at another Bowland site, found breeding at the same territory in the following season (2008). This detail was taken from “The Upland Breeding Report for the United Utilities Forest of Bowland Estate 2008 report, and therefore we must accept as correct.
Quote De-facto:
Let me try and end all the speculation once and for all. On the 27 July an inexperienced field police worker visited the area above the 2007 nest and recovered what he believed were hen harrier feathers. The corpse of a recently dead harrier was also recovered from the same location. After this detail had been given to the Crime Officer and Natural England, misleading and quite frankly inappropriate information was then leaked to the Shooting Times which they then published as fact.
I assume the said inexperienced police field officer held a Schedule One licence, or was accompanied by an experienced licence holder when he visited the nesting area. If neither was the case then why was he visiting a Schedule One species alone, and why has no one confronted him for an explanation, or have they? It just adds another thread to what is already a possible illegal placing of dead Schedule One species, (namely Hen Harrier) near to the nest of a contraversial species like Eagle Owl. He may be completely innocent but it does make you wonder, and why was it so quickly released to the Shooting Times by the Crime Officer!