Two Manx Hen Harriers die of natural causes

It does happen – it’s strange that we don’t hear more about Hen Harriers dying of natural causes.

The RSPB has released information on the deaths of two young Hen Harriers satellite-tagged (as chicks) this year.

Mannin failed to complete the sea crossing between the IoM and SW Scotland whereas Grayse died on the IoM a few weeks after fledging.

Mannin left the IoM on 14 August and headed towards Scotland and died en route (we can safely rule out grouse shooting as the cause) but the satellite tag continued to function and was recovered, with Mannin’s body, on the shoreline near Kirkudbright on 24 August. It’s amazing what these tags can go through and still transmit data except on grouse moors where they seem very vulnerable.

As the RSPB says:

‘Whilst the deaths of both of these birds through natural causes is disappointing, the finding of their bodies and recovery of them and their tags was straightforward. As you would expect, their transmitters continued to provide us with good location data, even after one of them had spent ten days in the sea.

This is, however, in marked contrast to the disappearance of “Calluna”, whose perfectly-functioning tag’s transmissions ended very abruptly on 12th August. Her last recorded position was on a grouse moor, a few miles north of Ballater, in the Cairngorms National Park, and her disappearance can rightly be regarded as highly suspicious.

Here’s hoping that the ten remaining birds from the Class of 2017 continue to thrive and provide us with many more positive stories. You can follow them here.’

Ten days in the sea – they should use these tags on turtles!

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24 Replies to “Two Manx Hen Harriers die of natural causes”

  1. what an extraordinary statement for the RSPB to make:

    "Whilst the deaths of both of these birds through natural causes is disappointing..."

    why is it disappointing? Is the RSPB's objective to prevent all young Hen Harriers from dying before their allotted time, so they feel they have failed when one curl up its talons too soon. I hope not.

    Death of individual birds, lichens bees is a completely natural event - as is extinction of species (though not at the astonishing rates currently taking place) - I imagine there are some species which depend on Hen Harriers dying.

    I'm not suggesting we should celebrate the death of these individuals, but let's accept it happens (what would the normal mortality rates for fledgling Hen Harriers be?) - and is perfectly natural.

    1. I find yours a somewhat bizarre reaction. It's perfectly understandable that, having invested a lot of time and financial resources in tagging these birds, the RSPB should express disappointment that the birds died relatively prematurely thus denying them the sort of useful data that would have helped them to protect and sustain the population. Further, those doing this work are not automata and will inevitably have an emotional attachment to the birds they have worked with and so expressing disappointment is a perfectly reasonable and natural reaction. A press release isn't a peer reviewed scientific document and expressing such feelings therein is perfectly understandable.

      1. "perfectly understandable" ...

        ... when the loss of two individuals represents significant loss to the potential breeding population of a very rare species - for whatever reason

      2. fair enough John - but I think there is a danger that the messages are getting confused.

        Do all Hen Harrier deaths matter equally? or are Hen Harrier deaths on Grouse Moors the real issue.

        Press Releases, especially on such contentious subjects as Hen Harriers, should be handled with far more care than peer reviewed papers, as they will be read by many more people.

        1. I understand your point, Miles but there is a case for showing an emotional reaction in press releases that would be out of place in scientific context.

          1. Thanks John. To be fair, the wording was in the blog. I haven't found the press release, so I don't know if the same wording was used.

            The BBC has picked up the story and there is no mention of disappointment.

            I read the blog carefully (but only after I had shot from the lip with my comment). What came across was heartfelt sadness from the project staff, that the Harriers had not managed to survive. I am sure I would have felt just the same.

  2. Miles

    You are absolutely correct in assuming that some species depend on hen harriers dying. Red grouse is an example, heather is another. Neither would be as prolific in our NPs if hen harriers were more abundant.



    1. ho ho. I was thinking of the myriad of species that depend on other species dying - saprophytes. Some of the most threatened species are fungi and insects associated with the decay of animal bodies.

      1. Miles

        Expressing disappointment that two individuals of a rare breeding species whose population is artificially suppressed by illegal methods and actions is not to be derided. This is particularly acute for species where every death matters and can have significant population effects.

        As for your comments on saprophages, the death of a rare species will by definition have virtually no effect on the conservation status of saprophages unless they are solely reliant on that species. I cannot think of a single saprophage that is reliant on the hen harrier, or indeed any other vertebrate. Indeed, for saprophages to be successful, I suspect that they are either generalists, unfussy as to what the cadaver is, or associated with a family or genus at best. For a species to be specific on a single host must be rare and associated with a contained environment. Perhaps the cadavers of golden mole rats have a rare saprophage associated with them? But a wandering species such as hen harrier?


  3. Very sad news, but the birds were located & explanations for their deaths confirmed. It should be that easy shouldn't it? Over time the reliability of these tags will be undeniable and more weight added to the case against Driven Grouse Moor land management methods. The lives of Mannin & Grayse have not been wasted & their contribution to the survival of Hen Harriers in the U.K. are now etched in the history books.

    1. I agree it's sad, especially for the Hen Harrier workers on the Isle of Man who watched these birds grow up and hoped they would be successful.

  4. It might also be worth recalling the example of the Montagu's Harrier sat-tagged by the Dutch research team which expired in Senegal but whose still-transmitting tag was subsequently recovered 12 months after the bird had stopped moving.

    1. Miles - I see what you mean but it's a bit like my favourite passage of john Donne who almost said:

      'No man is an island entire of itself; every man
      is a piece of the continent, a part of the main;
      if a clod be washed away by the sea, Europe
      is the less, as well as if a promontory were, as
      well as any manner of thy friends or of thine
      own were; any harrier's death diminishes me,
      because I am involved in harrierkind.
      And therefore never send to know for whom
      the bell tolls; it tolls for thee.

      1. Thanks Mark.

        I guess this comes back to what you were writing about in British Wildlife; the cross-over (or lack of it) between conservation and animal welfare.

        I'd say I have a strong emotional connection to nature (which is a big part of what People Need Nature is all about). But for me, this does not usually mean a emotional connection with individual animals or plants.

        Having said that I was pretty upset when I thought a Butterfly orchid had been dug up on a nature reserve I used to manage. On reflection I concluded that it had been dug up by a rabbit. Perhaps I was kidding myself.

        1. Miles,think you should stick to plants.
          In this case nothing wrong at all with RSPB response,we all know HHs have some natural deaths but it is still sad when it is reported but it is the illegal persecution that we need to get on top of.

  5. It is disappointing to have lost these birds, we are probably so accustomed to persecution being the reason for Harriers dying that we have overlooked that they face other challenges in their early months.
    What is telling is that if they die naturally with Sat Tags on then retrieving them should be possible!

    1. Words again - possible or easy. What really this is showing is that when the birds die naturally it is EASY to find the bird and tag. When shot dead the bird and the tag disappears straight away and you can not find either unless you look on ebay!

  6. Thought - How about we satellite tag the shooters? Blue collar criminals get tagged. Tagging the white and blue collared shooters - we'll know when they approach the precious harrier nests...

  7. The whole point of satellite tagging Hen Harriers is to collect robust data that accurately reflects the birds movements and life expectancy. For this purpose all data is useful, even if it provides evidence of higher than expected natural mortality. However as has been pointed out above, the recovery of tags from dead birds under extreme conditions such as drowning in the sea, also provides increasing counter evidence to the tags which disappeared under mysterious circumstances on grouse moors. These tags are clearly robust and reliable. The more tags that are recovered from alternative locations the more evidence there is of suspicious disappearances when they cease to function on or near to grouse moors.

  8. Amazing that a tag was still working after a significant period in the water! I'm currently going through the excellent report that SNH did at the request of Roseanna Cunningham. and have to say that there's a hell of a lot of background info re the tags that I just didn't know. They really are incredible, designed to alert trackers if the battery is low or technical problems are developing, another reason why sudden cessation of signal is very suspicious. I've still got 150 pages plus to go, but it's fascinating stuff. Tags are only going to become better and cheaper - no wonder they are hated by some. One tag was found where the harness looked as if it had been cut and the tag itself had been stabbed by what was probably a knife - remarkably it still worked - no sign of the bird though.

  9. So, Miles, you think that the RSPB statement of being 'disappointed' that two young Hen Harriers have died a natural death is 'EXTRAORDINARY'

    What was your sentiment? Indifference?

    Do you think everyone should be INDIFFERENT to the premature death of rare birds if their deaths are natural? Do you think that being 'disappointed' really indicates a non-acceptance of natural death? Jeezus H Christ...

    And you even ask WHY the RSPB is 'disappointed' that two young, rare birds died prematurely? I will tell you WHY: because if they were not 'disappointed' the RSPB would not have gone to the trouble of tagging these birds in the first place. If the RSPB were not 'disappointed' they would not care about birds, and if people were not 'disappointed' they would not support the RSPB.


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