At long last, after years of stalling, hiding, prevaricating and obsfuscating (e.g. see here and here) and 13 years after its publicly-funded study began, Natural England’s hen harrier satellite tag data has finally been analysed and published in a peer-reviewed scientific journal.
The paper is open access and can be downloaded here: Widespread illegal killing of HH on British grouse moors
Here is the abstract:
The results? Entirely predictable (hen harriers are highly likely to be killed on grouse moors – gosh, who knew?), and are more likely to be killed inside protected areas such as National Parks and Areas of Outstanding Natural Beauty (AONBs) with large areas of grouse moors than any other type of landuse, especially these protected areas in North Yorkshire, Bowland and the Peak District:
Unfortunately the results do not have the same fine resolution as those of the golden eagle sat tag review, but that is simply a consequence of using different types of satellite tag and duty cycles. E.g. the golden eagle tags, especially the newer GSM solar powered tags, are ‘on’ constantly and are collecting data every minute when fully charged, whereas the hen harrier tags are using the Doppler/Argos system so the tags are less spatially accurate and have frequent periods when they are not ‘on’, thus not collecting data. Nevertheless, even being forced to undertake an analysis at a coarse scale, the results are still damning.
The most devastating result, in our opinion, is the extent of the criminality and this is what should be grabbing the attention of Ministers. Sure, we’ve all known for years that hen harriers are killed by gamekeepers on many driven grouse moors; everybody knows and acknowledges that, but the scale of the killing has always been challenged (or more usually, denied).
But this paper puts an end to those denials. 72% of the Natural England sat tagged hen harriers are presumed to have been illegally killed, versus 9% natural deaths. 72% is the MINIMUM value. If you exclude the tagged birds that are still alive/being tracked (7), and thus just look at the tagged birds with a known end fate, then the maximum value of illegally killed satellite tagged hen harriers would be 82% versus 9.8% natural deaths. It’ll be interesting to add the RSPB-tagged birds to this in due course.
82% of young tagged hen harriers are likely to have been illegally killed, on grouse moors. Compare that to the 31% of satellite tagged golden eagles that ‘disappeared’ in suspicious circumstances on or near driven grouse moors in Scotland. In a direct response to that 31%, Scottish Environment Secretary Roseanna Cunningham ordered an independent review of grouse moor management, specifically to examine opportunities for licensing.
How do you think her Westminster counterparts, Michael Gove & Dr Therese Coffey will respond to the 82% figure? Let’s see, shall we?
A press release has been issued by the partner organisations involved in the hen harrier sat tag analysis, as follows:
STUDY SUGGESTS WIDESPREAD ILLEGAL KILLING OF HEN HARRIERS ON ENGLISH GROUSE MOORS
A new study reveals that young hen harriers in England suffer abnormally high mortality compared to populations in Orkney and mainland Scotland and the study provides compelling evidence that the most likely cause is illegal killing in areas associated with grouse moor management.
Published today in Nature Communications, this paper represents the culmination of a 10-year Natural England study involving 58 satellite tagged hen harriers. The analyses have been led by the University of Cape Town and Aberdeen University with the provision of land use data by the RSPB. The study showed the likelihood of hen harriers dying, or disappearing, was ten times higher within areas predominantly covered by grouse moor, compared to areas with no grouse moor. The study revealed that 72% of tagged harriers were either confirmed or considered very likely to have been illegally killed.
The hen harrier, sometimes called the ‘skydancer’ because of its amazing acrobatic display in the breeding season, is one of England’s rarest birds and is legally protected. Illegal killing of hen harriers has long been thought to limit their population size, but identifying the scale of these crimes and their impact on harrier populations has been difficult because they occur in remote areas and evidence is likely to be destroyed, thus successful prosecutions are rare. This long-term study has enabled patterns of disappearances to be assessed across a large number of birds. This provides overwhelming evidence that illegal killing is occurring on some grouse moors, where some gamekeepers view hen harriers as a threat to their grouse stocks.
Stephen Murphy from Natural England led the data collection and commented: “Natural England welcomes the publication of this study, which demonstrates the value of tagging as a legitimate conservation tool. These analyses are a significant step in understanding the fate of tagged hen harriers, and confirm what has long been suspected – that illegal persecution is having a major impact on the conservation status of this bird.”
Dr Megan Murgatroyd, from the University of Cape Town, who is the lead author of the study said: “Natural England’s long-term commitment to this tracking study has yielded an important dataset involving over 20,000 individual fixes. This is a remarkable achievement for a species whose population in England has averaged only a handful of pairs for the last few years. Whilst dead harriers can be disposed of, the pattern of hen harrier disappearances revealed by this data could not be hidden. [Ed: She’s clearly been listening to Dr Hugh Webster – that’s his line!] The multiple levels of analyses of the data have all led to the same robust conclusion that hen harriers in Britain suffer elevated levels of mortality on grouse moors, and this is most likely the result of illegal killing.“
Dr David Douglas, RSPB Principal Conservation Scientist and a co-author on the paper, said: “The high rate of illegal persecution on grouse moors revealed by this study goes a long way to explaining why hen harriers are barely hanging on as a breeding bird in England. Satellite tag data is giving us very valuable insights into what is happening to our birds of prey in the UK. It has already provided compelling evidence of the link between suspicious golden eagle deaths and grouse moors in Scotland and now it has done the same for hen harriers in England.”
Rob Cooke from Natural England said: “Natural England will continue its satellite tracking work to further improve our understanding of hen harrier movements and behaviour, and will continue work to improve the conservation status of the species. Natural England welcomes the support of many landowners in this, and will continue to work with all landowners and other interested parties to find ways of enabling hen harrier populations to increase from their current critically endangered levels in England”.
[Satellite-tagged hen harrier Carroll, who’d been shot]
UPDATE 20 March 2019: Responses to hen harrier satellite tag paper: Supt Nick Lyall, Chair RPPDG (here)
UPDATE 21 March 2019: Responses to hen harrier satellite tag paper: BASC (here)
UPDATE 21 March 2019: Responses to hen harrier satellite tag paper: DEFRA Wildlife Minister Dr Therese Coffey (here)
UPDATE 22 March 2019: Responses to hen harrier satellite tag paper: Northern England Raptor Forum (here)
UPDATE 24 March 2019: Responses to hen harrier satellite tag paper: Moorland Association (here)
UPDATE 25 March 2019: Responses to hen harrier satellite tag paper: GWCT (here)