Hen Harrier nest
The published Hen Harrier breeding data for 2020 has been heralded as a huge success in some quarters, but was it? There has been much back slapping from Natural England’s senior management, the Moorland Association, GWCT and BASC et al. Congratulations are offered all round with the claim that the Hen Harrier Action Plan is working. Cue brass band.
There has indeed been an increase in both the number of successful nests and the number of fledglings and this is to be welcomed. Sixty young from 19 successful nests; 3.2 fledglings per nest is within the range that we would have expected in a year when the weather in June was very favourable. Interestingly in the Natural England press release Tony Juniper is quoted as saying “2020 has seen the best breeding season for England’s hen harriers in years………………” but he fails to mention that there were actually 24 breeding attempts during 2020, 5 of which failed. We will return to this later. According to Natural England’s own data there were 23 breeding attempts in both 2003 and 2007 [A future for the Hen Harriers in England 2008]. Therefore an increase from 23 to 24 isn’t very much to celebrate and doing so is a classic example of ‘Shifting Baseline Syndrome’. The collapse of the Hen Harrier population has been accepted in some quarters, and welcomed in others, as the inevitable, unassailable consequence of the purported conflict between driven grouse shooting and Hen Harriers for decades. Society, including those members who have a duty to protect Hen Harriers, has come to accept a population range between 1% and 5% [3 – 15 pairs] of its agreed potential, is the acceptable norm. Therefore any increase beyond 15 pairs, no matter how small, is seen as something to be celebrated. It is not. If we are to achieve the goal of allowing the Hen Harrier population to increase in proportion with the available, suitable habitat then ‘Shifting Baseline Syndrome’ must be avoided.
Whilst the numbers are an improvement on recent years we shouldn’t get carried away with that. What we should be celebrating is that 330 pairs fledged 3.2 chicks per nest in England, not 19. One thousand chicks entering the population; imagine that. Unfortunately, imagining that prospect is probably all that many of us will ever be able to do. Interestingly, whilst a BASC statement welcomes the increase and acknowledges that there is much to do it also goes on to say “This figure means we are only 30 per cent of the way towards a sustainable English breeding hen harrier population”. If that comment accurately reflects BASC’s position and they are indeed suggesting that 20 nests represents 30% of a self-sustaining population then are they also implying that the English Hen Harrier population of 66 pairs is acceptable. Acceptable to whom? Is that their target population? Sixty-six pairs is only one-fifth of the projected carrying capacity in England.
Other than there being enough breeding birds in the population to raise young, the most important fact leading to increased productivity is prey availability. We know that in 2020 there was a ‘vole plague’ i.e. a plentiful and consistent food supply throughout the breeding season, in some of the breeding areas. The consistent availability of prey and in some cases the provision of supplementary / diversionary feeding understandably led to increased productivity. However, the situation will undoubtedly be reversed in future years when prey availability crashes and / or the demand for the provision of diversionary feeding exceeds the capacity to deliver it, either financially or physically.
Natural England claims that 2020 was a record year, however productivity is only a measure of breeding success. Survivability is the measure of population expansion. In the past according to the analysis of Natural England’s data 72% of satellite tagged birds were killed or very likely to have been killed on a grouse moor. Their landmark paper also revealed that Hen Harriers are likely to die or inexplicably disappear without trace was 10 times higher, yes 10 times higher, on grouse moors when compared to none grouse moors. “Patterns of satellite tagged hen harrier disappearances suggest widespread illegal killing on British grouse moors”. Murgatroyd et al 2019. We won’t know for 1 or 2 years whether or not 2020 was a good year for Hen Harriers. Knowing that 72% of satellite tagged birds are killed or likely to have been killed on grouse moors it is not unreasonable to suggest that 72% of un-tagged birds suffered the same fate.
By making small assumptions and rounding the numbers to make the calculations less technical and using Murgatroyd et al as a base, we can predict what the final outcome will be for the 2020 cohort. Starting with 60 chicks, assuming that 32 were tagged we can predict that 75%, 24 individuals, will be killed or assumed to have been killed on grouse moors. Presuming that 75%, an additional 24 individuals, of the un-tagged birds were also killed or believed to have been killed on grouse moors during the same period, a total of 48 birds joined the ‘disappeared’ during the first year. The 12 remaining chicks, 20% of the original cohort, are not immune from dying and an unknown number will succumb to natural causes. The final number of chicks surviving their first year will depend largely on the availability of prey and the ferocity of the winter but is likely to be less than 12. Before people attempt to ridicule these calculations as ‘back of an envelope’ speculation they should read data published by Natural England in 2019. That data looked at 58 chicks and predicted that only 17%, less than 10 individuals would survive their first year. A very similar outcome to the one we predict for 2020.
The exact proportion of birds being killed or assumed to have been killed on grouse moors, revealed by Murgatroyd et al, may have come as a shock to some but the fact that persecution remains a limiting factor to population expansion is well documented and should not have come as a surprise. In 2008 Natural England published a paper in which they said; “There is compelling evidence that persecution continues, both during and following the breeding season.” The paper went on to say “Persecution continues to limit Hen Harrier recovery in England”. [A future for the Hen Harrier in England 2008.]
Natural England have produced two documents that unequivocally state that persecution is the primary problem limiting Hen Harrier population expansion. However, in Natural England’s latest press release Tony Juniper is quoted as saying “Although persecution is thought to be the main factor limiting hen harrier numbers in England”. At what point did Natural England’s evidence based statements that persecution is the main issue limiting population expansion become a ‘thought experiment’?
NERF is a member of the Raptor Persecution Priority Delivery Group [RPPDG], and as such is a consultee under Action 4 of NE’s Hen Harrier Recovery Plan. The paper can be found at https://www.gov.uk/government/publications/increasing-hen-harrier-populations-in-england-action-plan . Yet when Natural England went in search of supporting comments for their press release they only published comments from the shooting industry. Perhaps Natural England would like to explain why that was the case. They may also want to explain why NERF wasn’t included in the list of organisations working in partnership for the benefit of Hen Harriers.
NERF is at the forefront of Hen Harrier nest finding and monitoring during the breeding season, ringing, satellite tagging and winter roost monitoring in partnership with the RSPB. Despite this, we weren’t approached for a comment when Natural England published their press release. If we had been asked for and provided a comment we doubt that it would have been published. Natural England should be in no doubt that without the dedication of NERF members who commit hundreds of voluntary hours to monitoring and self-fund thousands of miles to monitor Hen Harriers the species would be in a much worse state than it is currently.
NERF is also concerned that the press release failed to acknowledge that there were in fact 24 active nests at the start of the breeding season. Two nests were being provisioned by a polygamous male and when he joined the ‘disappeared’ both nests were understandably abandoned. Two other nests, both of which were known to contain eggs, failed during the Covid-19 lockdown period when conservation staff and volunteers were prohibited from monitoring nests. There is every possibility that these 4 nests failed as a result of persecution and yet they don’t even warrant a mention in the press release. The 5th nest appears to have failed due to predation. Why didn’t Natural England, the Moorland Association or GWCT mention these failures in their statements? Were they attempting to bury bad news rather than being upfront and transparent by publishing all of the nest data in their press release?
Before the celebrations get out of hand we need to take a closer look at land ownership and usage and overlay that with the breeding data. Only by doing that can we develop a new understanding of the breeding success and its relationship with driven grouse shooting in 2020.
The shooting industry are claiming credit for the success because some of the nests were located on grouse moors. However, how relevant was that claim? How many of the 19 successful nests were actually successful solely on the basis that they nested on land managed for grouse shooting and for no other reason? The Moorland Association tell us that the answer is 12, more than 63%. That sounds impressive, but a closer look at the data suggests that when all other factors are considered it is not as impressive as the press release would have us believe.
In reality two nests were brood managed and they should be deducted from the Moorland Association’s claim on the basis that the young from these nests were raised in captivity, not on a grouse moor. Additionally the remaining nests in those brood managed clusters should also be deducted because they were required to be protected as part of the brood management scheme.
Four of the remaining nests were in the South Pennine SPA on United Utilities land in the Forest of Bowland, albeit it with a shooting tenant, and where therefore afforded special protection. Of the remaining nests, 1 nest was on a hill farm with a shooting tenant and both the farmer and tenant were unconcerned that the pair were breeding and both were actively supporting the local Raptor Workers who were monitoring the nest.
Whilst we accept that land with grouse shooting interests can be loosely classed as a grouse moor it should only be done so in the context that the landowner has control over the property. The tenant will be bound by contractual obligations which may include complying with current legislation and face the risk that the contract will be terminated in the event of a breach.
The remaining nest was located on what Raptor Workers and raptor conservationists would recognise as a private, traditional driven grouse moor. The nest was monitored from over the fence line by NERF members and the owner was aware of this.
The spin free results are not as impressive as we were led to believe. Why does Natural England’s senior management and the shooting industry representatives feel that it is necessary to use spin in this way? The data shows an increase, not staggeringly so, but an increase non-the-less. Of course the shooting industry will insist that whilst the primary land use may not be grouse shooting the land is managed for that purpose and the management techniques used benefit all ground nesting birds, including Hen Harriers. The discussion about the alleged benefits of grouse moor land management is for another day.
Before the celebrations begin we need to see the brood management scheme abandoned and year on year increases in both breeding success and chick survivability on land that is primarily used for grouse shooting. Those are the only measures that we should be using to quantify success. It is only when Hen Harriers are breeding on private grouse moors across the whole of the northern uplands that we may allow ourselves a little optimism for the future of a species that remains in peril.
Sorry brass band you can stand down. The fanfare has been cancelled for this year, again, and we won’t be keeping your number on speed dial for the time being at least.
11 September 2020