The RSPB is being criticised by the usual suspects (The Daily Telegraph, the Daily Mail and also the shooting press) for the number of Hen Harrier nests that failed on its watch last season. We’ve been through this several times recently, including getting the Daily Telegraph to correct its earlier version and to apologise for it.
For the RSPB account of the year – click here.
For the Natural England account of the year – see here.
The fact that six out of nine nests with which the RSPB was involved failed, and one of these was on one of its nature reserves, certainly doesn’t look great. In fact it’s a bit suspicious. But not, to my mind, in the way that YFTB has suggested.
Let us just consider the nests from which male Hen Harriers disappeared. I don’t think there is much dispute that there were five such nests – four at Bowland and one at Geltsdale.
All of the failed nests (whether they were ones where males disappeared or not) were near grouse moors. None of the successful nests was on a grouse moor (I don’t know how many were near grouse moors – maybe all of them for all I know).
The RSPB was involved with 9 Hen Harrier active nests from which 5 males disappeared.
What is the chance that a male Hen Harrier will disappear from an active nest? Well, we’ve already heard from an experienced wildlife photographer who has never seen it happen! But it must happen now and again because Hen Harriers don’t live for ever. According to the BTO male Hen Harriers have an annual survivorship of about 72% per annum. So that means there is a 28% chance of any particular bird dying each year. In the two months when attending an active nest, say, the chance of a Hen Harrier dying must be, on average, about 5% then (assuming various things).
So, if you have 9 nests with RSPB involvement, and males disappear from 5 of them, the probability of that happening by chance is something like 0.05 x 0.05 x 0.05 x 0.05 x 0.05 x 0.95 x 0.95 x 0.95 x 0.95 x 126 = about 0.00003 (or less than three in a hundred thousand). [As I wondered – my original version wasn’t right – but the right version is an even smaller number! thank you for the correction].
So, if there is such a tiny chance that, given the survival rate of male Hen Harriers, you would expect that many males to disappear from the nine nests, either RSPB involvement is a spectacularly bad kiss of death for Hen Harrier nests (which seems to be YFTB’s view) or something else is happening. [And, of course, removing the 2 successful FE nests with which the RSPB had an involvement would make the chance of 5 males disappearing from 7 nests even less likely – I think it is about 1 in 1,000,000].
I think something else is happening. I do wonder whether males from the nests with RSPB involvement were deliberately targetted so that there was the possibility of producing headlines of the type we have seen. I have no idea who might have done this. But I wouldn’t rule out coordination of this type of activity. All it requires is that male Hen Harriers in Bowland and Geltsdale are illegally killed and we know that that sort of thing certainly goes on on some grouse moors by person or persons unknown.
And it would be even better if a few pairs were left, deliberately, to survive on or near grouse moors for comparison – remember the Telegraph started with a 6-0 story.
Now, I know that watches of harrier nests by RSPB and others are done from a distance of many hundred yards (depending on terrain) and that in some cases cameras are put a bit closer to the nests.
The chances of disturbing a male (rather than the female who, of course, is at the nest throughout) through nest-guarding is very very low. Not zero, but getting pretty close to it. But this is what some in the shooting community have suggested has happened – not just to one nest but to five of them.
This is entirely lacking in credibility to my mind. If one nest failed because of disturbance I’d be very surprised – gobsmacked in fact. If it did fail, I’d expect the male to be seen in the area afterwards rather than disappear. And I’d expect, all other things being equal, the female to be more likely to disappear than the male. For five nests to lose their males – for the males to disappear – is indeed highly suspicious.
So suspicious that it does make me wonder whether they were deliberately targetted. And deliberately targetted to produce lurid headlines and stories of the sort for which the Telegraph had to apologise.
So was there a smoke-filled room (there are very few of them these days) somewhere, some time last winter, when this plan was hatched? Was it a cunning plan? Or is that just fanciful? If you were in any such smoke-filled room, then please do get in touch.
What do you think?
And if you can correct my maths I’ll be very grateful – although I am sure that the general thrust of this blog will remain unaffected.