I’m sorry to have to report that we have lost another of this year’s satellite tagged hen harrier chicks.
Brian, named after the very experienced raptor worker Brian Etheridge, was one of our non-public-facing birds. With the permission of the landowner and help of local Scottish Raptor Study Group members, he was tagged as part of the Hen Harrier LIFE Project on 4th July on an estate in Perthshire within the Cairngorms National Park. He fledged from the nest and stayed close to the nest site until the beginning of August when he moved north into southern Inverness-shire. Brian then spent the next few weeks over various areas of managed grouse moor, within the National Park with frequent strong, clear transmissions from his tag providing detailed information about his daily travels.
Brian having just received his satellite tag (photo: Jenny Weston)
Suddenly and without warning, these transmissions stopped on 22nd August. There was no indication of battery failure or other technical problems. His last recorded position was a few miles from Kingussie, though he may have travelled some distance before his satellite tag stopped. Despite a thorough search of the area with landowner cooperation, his body could not be found.
Brian is the fourth satellite-tagged hen harrier to suddenly disappear off radar this year, after our 2014 birds Highlander and Chance vanished in County Durham and South Lanarkshire respectively this Spring, and 2016 bird Elwood disappeared in the Monadhliaths last month.
The Scottish Government has ordered a review of satellite tracking data, following reports of the disappearance of a number of golden eagles in the Monadhliath mountains. Roseanna Cunningham, Cabinet Secretary for Environment, Climate Change and Land Reform, said:
“The latest reports of satellite-tagged golden eagles disappearing on or near grouse moors are very disturbing and disappointing.
“That is why I have instructed officials to analyse the evidence from around 90 surviving and missing satellite-tagged eagles, to discover if there is a pattern of suspicious activity.
“Grouse moor management does help species such as curlew and golden plover as well as generating much needed rural employment and income but this cannot be at any price.
“The public rightly expects all businesses in Scotland to obey the law. Let me be clear: grouse shooting is no exception.
“As previously stated, the Scottish Government is prepared to introduce further regulation of shooting businesses if necessary. It will be unfortunate if the activities of a few bring further regulation on the whole sector, but that is the risk those who defy the law and defy public opinion are running.”
This review has recently been expanded to include data from hen harriers and red kites. We welcome this review and look forward to the report on its findings.
It's now a case of all fingers and toes crossed for our remaining young satellite-tagged hen harriers. You can follow the fortunes of 10 of these birds online at www.rspb.org.uk/henharrierlife or @RSPB_Skydancer.
Since the publication of this blog, we've received an unprecedented number of requests to reveal Brian’s last known location. In publicising the disappearance, in suspicious circumstances, of any satellite-tagged birds, we have always been careful to avoid naming specific land holdings as it would be unfair to implicate individuals when, as already acknowledged, the birds are likely to have moved some distance from where they were last recorded.
We'll make an exception in this particular case because the bird roosted the night before on our Insh Marshes reserve whilst in the daytime ranging out on surrounding moorland, before he disappeared. But as stated in the original blog, the last received location is only an indication of the broad general area in which Brian was spending time. This was true of our hen harriers, Highlander, Chance, and Elwood, all of whom disappeared earlier this year, and why we haven’t previously named estates or specified last known locations.
The key point is that in all cases, satellite tags that were transmitting loud and clear and showing no sign of technical problems suddenly ceased transmitting, in circumstances strongly indicating that the tags had been destroyed. As in previous cases, a search was made of the last location where “Brian” was recorded, with no sign of the bird found.
Not my inference Blanaid, but that of TeeJay and Clare below.
The mentioning of the ScotGov review of satellite tagging data is relevant because the latter has been expanded from golden eagles to include data on hen harriers and red kites. As such, the data from Brian's tag will be included in the review. Any interpretation of this as implying association with persecution is your own inference.
I think you’ve missed my point. The point was that rather than fuelling unhelpful speculation by conflating every loss of satellite signal (not radar tracking by the way) from tagged birds with possible or alleged persecution – by including Roseanna Cunningham’s press release on losses of satellite signal from tagged golden eagles in the Monadhliaths - it would be better to treat each instance, individually. And to take into account all the regional and local circumstances - such as the issue of fox/badger predation at Insh Marshes, and possible associated causes of loss of satellite signal, satellite tag failure and/or satellite transmitter shielding.
No radio or satellite transmitter’s signal will be received if the aerial is destroyed, damaged or shielded, from whatever cause, see here - http://tinyurl.com/zdakpzj. And fox’s teeth and jaws are quite capable of puncturing and rendering a satellite tag, its aerial and/or battery inoperable.
I am not asserting that natural predation (by fox/badger) was responsible on this occasion, but it is as plausible an explanation - given the local circumstances and conditions - as any other.
Foxes do predate hen harriers, just as they predate many other ground nesting birds. This is something we freely acknowledge. However, satellite tags are small and very durable pieces of kit that would require precise and concerted chewing from a fox to destroy to the point of ceasing transmission. I’m sure there are much tastier bits of a hen harrier that a fox would rather focus on.
You say we must look at the facts and the facts available to us show that when birds die naturally, we tend to find them - last year’s Hetty on the Isle of Man for example. The facts surrounding Brian’s disappearance mirror those of our other hen harriers, Elwood, Chance, Highlander, Holly, Hope, and Sky before him. The weight of evidence across this bigger picture clearly indicates that there are factors at play beyond natural predation.
That said, when it comes to individual cases without a physical body to examine, it is as erroneous and unhelpful for you to assert natural predation as the obvious cause, as it would be for us to assert persecution as the cause - which if you read the blog again, you’ll note I didn’t. In fact, I didn’t speculate as to the cause of Brian’s disappearance at all.
On 20th June, Martin Harper blogged that trail cameras at Insh Marshes had identified foxes and badgers as being the most likely reason for poor lapwing breeding success at the reserve and went on to state that lethal control of the foxes was being considered as a management option for next year – see here http://tinyurl.com/hhmotxe
We know from nest cameras monitoring breeding HHs in a Skye study area that fox predation was the major driver of HH breeding failure over the last couple of years - robyorke.co.uk/.../Skye-harrier-nest-predation-report.pdf. Moreover, further nest camera evidence from Langholm this year showed a fox grabbing a young near-fledged harrier from one nest. The increased usage of trail cameras has thus unequivocally identified foxes as a major predator of HHs. And RSPB trail cameras at Insh Marshes have identified that foxes regularly forage there. We also know that HHs have a high mortality rate in their 1st year (D. Watson 1977, The Hen Harrier).
Moreover, as we are all aware, a satellite tag is unlikely to continue functioning after being chewed (along with the prey’s bones, feathers etc) by a fox or badger, and/or after being cached or taken to an underground den or sett, or lying under a carcass with the transmitter shielded by the corpse, vegetation, terrain etc.
So, an entirely plausible explanation for this loss of signal would be mammalian predation of a naïve juvenile bird at a fox-rich roosting site or when on the ground with prey.
Wouldn’t it therefore have been better to release the full facts straight away, rather than disingenuously allowing unhelpful speculation to fuel further paranoia and polarisation in the conservation community?
The key point surely is not to conflate these unexplained losses of satellite signal from tagged birds, but to treat each loss of signal on a case-by-case basis and on the often very few facts pertaining.
Anyway, glad to hear that the landowner 'cooperated' in the thorough search of the area…..
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