This is a guest blog by Mike Whitehouse.
WHAT HAPPENED TO THE 58 HEN HARRIERS? THE UNANSWERED QUESTIONS BEHIND NATURAL ENGLAND’S BROOD-MANAGEMENT EXPERIMENT
I have followed the fortunes of Hen Harriers for many years. My concern is straightforward. I wanted my children to be able to see these magnificent birds flying over the northern uplands as a normal part of our wildlife, not as a rare and precarious privilege.
That is why I have taken a particular interest in Natural England’s Hen Harrier Brood Management Trial.
The trial has now finished. The licence period ran from 2018 to 2024, with brood management actually taking place between 2019 and 2023. Natural England published its final evaluation in July 2026.
But there remains one rather obvious question.
What happened to the birds?
58 birds were released
During the trial, 59 chicks were taken into captivity and 58 were eventually released.
Of those 58 released birds:
- 39 were fitted with satellite tags
- 19 were released without satellite tags
The satellite tags were intended to provide a means of monitoring survival and, where a bird died or disappeared, potentially investigating what had happened.
Indeed, Natural England explained the theory behind the trial quite clearly. If brood management reduced conflict with grouse shooting interests, this should lead to reduced persecution, improved survival and ultimately more Hen Harriers breeding in the wild.
So the fate of those released birds is rather important.
What happened to the 39 tagged birds?
The final evaluation contains the status of the satellite-tagged brood-managed birds at the end of the trial.
At the December 2024 endpoint, three were still alive and actively being tracked.
For the other 36 tagged birds, there was no current evidence of survival from the satellite tracking data.
That statement needs some careful qualification.
According to RPUK two of those 36 birds had in fact already been found dead and have been included in their running tally of 149 missing/killed Hen Harriers.
They were:
- R2-F2-20, brood-managed in 2020
- R3-F1-22, brood-managed in 2022
Both birds had spent the winter of 2022 at the same North Pennines roost.
This distinction matters because the deaths were not discovered after the trial. What happened after the trial was that Natural England finally published the details, on 18 December 2024, after the relevant police investigations had concluded.
Two birds found with shotgun pellets
The post-mortem examinations found three suspected lead shotgun pellets in R2-F2-20 and two suspected lead shotgun pellets in R3-F1-22.
Natural England nevertheless said that their presence suggested ongoing illegal persecution of Hen Harriers in northern England.
And what about the other 34 tagged birds?
This is where the numbers need to be handled carefully.
The 39 tagged birds comprise:
3 alive and actively tracked at the end of the trial
Plus
36 for which the tracking record provided no current evidence of survival at the December 2024 endpoint.
Two of those 36 had subsequently been recovered dead, with shotgun pellets in their bodies.
That leaves 34 tagged birds for which there is no documented evidence of subsequent survival.
Then in addition, there are also the 19 birds which were released without satellite tags.
Natural England has told me that it believes all the brood-managed birds were ringed and that the ringing records were shared with the British Trust for Ornithology.
But Natural England’s Hen Harrier Team has told me that it holds no record of the fates of the brood-managed birds that were not fitted with satellite tags. That leaves an important information gap.
A summary of the 58 birds released:
- 3 were alive and actively satellite-tagged at the end of the trial
- 2 were subsequently confirmed dead, both with shotgun pellets in their bodies
- 34 tagged birds have no documented evidence of subsequent survival
- 19 untagged birds have no fate record held by Natural England
In other words, 53 of the 58 released birds currently have no documented evidence of subsequent survival. That does not mean that 53 birds are known to have died. It does mean that, on the information currently available, there is no documented evidence establishing that they survived.
That is an important distinction.
Did brood management actually increase the Hen Harrier population?
This is perhaps the most interesting part of Natural England’s final evaluation.
The answer is not simply that 58 captive-reared birds caused the subsequent increase in Hen Harrier numbers.
Natural England itself says the number of brood-managed chicks was far too small to explain the substantial increase in nesting pairs.
The population modelling commissioned from the British Trust for Ornithology indicated that the increase was more consistent with higher survival and greater settlement and breeding by wild birds.
Natural England nevertheless concluded that the availability of brood management probably contributed to population growth, particularly through increased breeding on some grouse moors.
But there is an important qualification.
Natural England acknowledges that the effects of brood management could not be completely separated from the satellite tagging, monitoring and surveillance programme that accompanied it.
That makes the question of what actually drove the recovery more complicated than simply saying that brood management worked.
And what about persecution?
Natural England’s own conclusion is also quite clear on this point.
Illegal killing continued throughout the trial.
The final evaluation says that illegal killing remains a significant constraint on Hen Harrier recovery and that the trial did not demonstrate a widespread reduction in illegal killing.
That is particularly relevant when considering the fate of the brood-managed birds.
What did the experiment actually cost?
This is another area where the full picture is not yet available.
It said that Hen Harrier monitoring and recovery work overall had been estimated at hundreds of thousands of pounds annually, involving several directorates, but that it did not hold a detailed breakdown of their work.
Following an Environmental Information Regulations request, Natural England disclosed £83,613.50 of identifiable external expenditure associated with the work I asked about.
That included:
- £3,291.50 for satellite-tag data extraction in 2022
- £49,999 for the 2024 National Centre for Social Research study
- £30,323 for the British Trust for Ornithology population modelling
Natural England also said that two of the reports were produced internally and therefore did not have separately identifiable external costs.
However, Natural England did not provide a complete internal staff-cost figure for the trial.
There are also questions about the satellite tags themselves. Six reconditioned tags were supplied in 2023 but no costs were shown* against the remaining 33 tags or for the cost of their transmissions and associated data services.
So £83,613.50 cannot be presented as the total cost of their brood-management experiment. It is just the identifiable external expenditure Natural England has so far disclosed. I have therefore asked Natural England for further clarification.
What did Natural England actually learn from this financially costly experiment that displaced these birds, raised them in captivity and released them back into a predatory environment, where the majority of them were likely to be never seen again?
The unanswered question
Natural England has now concluded that the brood-management trial contributed to an increase in Hen Harrier nesting on some grouse moors.
It also accepts that the numbers of captive-reared birds were too small to explain the overall increase in wild bird survival and that the effects of brood management cannot be completely separated from the intensive tagging and monitoring programme, and that illegal killing continued throughout the trial.
Against that background, I keep coming back to the birds themselves.
58 were released.
39 were satellite tagged.
3 were still alive and actively tracked at the end of the trial.
Two others had already been found dead, both with shotgun pellets in their bodies.
34 tagged birds have no documented evidence of subsequent survival.
19 released without satellite tags for which Natural England says it holds no fate records.
That is a remarkable amount of uncertainty surrounding the fate of birds that were deliberately taken from the wild, raised in captivity and released as part of a scientific experiment.
The obvious next step is surely to find out what can still be established.
Were any of the 19 untagged birds subsequently seen?
Were any identified through their rings?
Does the BTO hold records that Natural England does not?
And, more broadly, what happened to the birds once the experiment stopped?
I have therefore approached the relevant organisations for any additional records they may hold.
Because ultimately, whatever one’s view of brood management, these were not numbers on a spreadsheet. They were 58 individual Hen Harriers and we should be able to account for what happened to them. They represent a significant cohort of Hen Harriers in England.
Natural England itself says that illegal killing continued during the trial and remains a significant constraint on Hen Harrier recovery.
So if persecution remains a problem, should conservation policy concentrate on finding ways of making Hen Harriers more acceptable to grouse shooting interests?
Or should it concentrate much more heavily on ensuring that a protected bird is actually protected?
That is not an argument against every grouse moor manager. There are undoubtedly estates and individuals who genuinely support Hen Harrier conservation.
But the continuing disappearance of protected birds means that the question cannot simply be ignored. I started campaigning because I wanted to see Hen Harriers flying over the northern uplands as a normal part of our wildlife not as a rare and precarious privilege.
ENDS
*Ed: it’s my understanding that the Moorland Association paid for the costs of the satellite tags used during the trial. It’s also my understanding that the Moorland Association paid the brood meddling licence holder, Jemima Parry Jones of the International Centre for Birds of Prey, for the costs of the removal of HH chicks from the moors, the costs of holding them and rearing in captivity, and the costs of their subsequent release.
Of the 34 remaining tagged birds, surely there’s a record of their movements and final recorded locations? 🤔
It seems bizarre that if this was a scientific trial into whether brood management worked, in among many things whether persecution diminished, why is the fate of so many of these birds unknown? Surely if they had satellite tags attached, staff involved would have had the opportunity to follow and record the fate of these several dozen birds? What a waste of time, effort and money otherwise and this whole farrago sums up the obfuscation and delaying tactics that moorland landowners and managers employ, with the consent of our environmental watchdogs. Time to end these cosy relationships and ban shooting on our moors for good as our rural “custodians” can’t be trusted
Speaking as the holder of a degree in environmental sciences, this was not in any way manner or form a scientific study. Actually, I could say that just from some basic knowledge of scientific methods…
It was PR flummery to try to keep shooting interests onside and was never going to show anything much of any use.
As it happens, it’s even worse than that: so little usable information has come out of it that it raises even more questions about the lack of thought going into it.
This creates more questions than it gives answers. The whole project was meant to assess whether ‘brood-managing’ helped the population yet, at the end of the trial, we know the fate of less than 10% of the birds involved. What investigations were carried out where the tags were no longer working? A potential ‘failure rate’ of 29 out of 34 tags is most unusual, yet none of the 29 were subsequently found. Does the manufacturer have a view or did they all happen to stop working in a known black spot for persecution? We need to know. What was the point of leaving 19 birds ringed but not tagged? Were none of the untagged birds spotted or the rings subsequently reported?
It seems a very leaky experiment that provided little conclusions. Even their one of saying it may have played a part in the increased number of HH seems based on wishful thinking rather than science based fact.
The experiment looks like the sop we always felt and feared it would be.
It would be interesting to see the historical statistics of Harrier breeding efforts & outcomes on the specific grouse moor Estates’ landholdings where nests were monitored and chicks were taken from. A useful comparison could be made on the situation before, during and after the brood meddling scheme. I know that this info is known to the raptor monitor groups and probably to Natural England monitors too, but there is maybe a wariness of legal troubles if they present names of estates. I believe it would show that some expert raptor killers fingers were kept off their semi -auto shotgun triggers on some estates during the scheme, but that they went quite quickly back on to the triggers when it ended.
Reason being – I believe that although the whole charade was rolled out under the guise of “research” some people were definitely given the discreet “nod” to “hold back, put up with it for a while” because this was in fact to be the start of a longer term plan that would evolve into a type of “raptor removal licence”. Where applications for individual numbers and species of previous protected “problem birds” would be received and granted whenever a land manager deemed it economically necessary. Who knows, had the Conservatives & friends remained dominant in the corridors of powers that might have been the future we could have had today i.e.”one nest per X thousand acres is more than plenty, you can snuff out the rest”.
The Conservative party wants to do away with Natural England and incorporate them into a new Environmental Crime and Enforcement Authority to target illegal dumping and wildlife crime, this may be a way forward because at the moment, NE is as useful as a chocolate firegurard
I suggest that the health of our environment and natural heritage has been, and still is, of very little interest to the tory party.
“The Conservative party wants to do away with Natural England and incorporate them into a new Environmental Crime and Enforcement Authority to target illegal dumping and wildlife crime, this may be a way forward because at the moment, NE is as useful as a chocolate firegurard”
Do you believe that ‘wildlife crime’ is all that concerns Natural England?
No, but they did borrow 58 Hen Harriers for their project. That in itself gives them some degree of responsibility surely ?
What question is this supposed to be an answer to?
What happened to the 58 Hen Harriers and Natural England ‘s involvement in this
There were many questions posed in this blog, the last of which asked “Or should it (Natural England) concentrate much more heavily on ensuring that a protected bird is actually protected?”
For example, is your answer to that “No”? I do not know which question you are replying “No’ to.
You initially asked “Do you believe that ‘wildlife crime’ is all that concerns Natural England?” My answer to you then was and still is “NO”.
In addition, I am very clearly of the view that NE spent an inordinate amount of taxpayers money on their project; in essence, to try and appease the shooting industry. I fully agree with the point you highlight. They they should have spent our money on ensuring that a protected bird is actually protected. Supporting the RSPB Investigations team would have been a good place to start, imo.
Agree with you. Also something very peculiar was made to occur with the NE harrier monitoring staff (i.e. the unbiased taxpayer employed civil servants) routine working practices and conduct around professional relationships. I believe the ones that do the twilight hunkering down at roosts on boggy moors in -10 wind chill are at heart good people. But when I heard who the “well known characters” – shall we say, were from some of the estates that they were obliged to go jollying about on the job with, I just couldn’t fathom what the hell was going on and who was fooling who. I still can’t fathom it. Maybe it’s me – I can’t function in that many “shades of grey” !
We know what happened to five of the sat tagged harriers in this sham project with certainty. The rest of those ” missing” satellite tagged harriers are almost certainly dead. If they had died natural deaths then transmitters continue to transmit and most would have been found and a cause of death determined. That this has not happened has all the hallmarks of persecution most likely by some in the grouse industry, their supporters or employees, with the culprits destroying or disabling the tags to hide their crimes. We largely through Ruth’s efforts through know this with statistical if not actual certainty. With those satellite tagged birds acting as a sample of the population it is most likely a similar proportion of the untagged birds have met the same fate.
As a ringer I know that it is very very unlikely the BTO have any data about the ringed birds ( ALL) that the ringers ( NE or associates) do not have.
The whole scheme was a pointless scam and that is what these results show, as the persecutors carried on regardless with just a shift in timing and perhaps technique.