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Excellent news on Hen Harriers – Mark Avery


https://naturalengland.weblog.gov.uk/2022/08/26/more-than-100-hen-harriers-fledge-in-england-for-the-first-time-in-over-100-years/

This information from Pure England may be very welcome – for 2 major causes. First, it’s excellent news, and second, it’s pretty informative and doesn’t look as if it was written by the capturing trade.

119 Hen Harrier chicks fledged from 49 nests (truly from the 34 profitable nests, and a few nests had been re-nests by the identical pairs) – because the NE weblog says, essentially the most in England for over a century. That’s fantastically excellent news to listen to.

The distribution of nests:

Bowland/Lancashire – 18 nests

Yorkshire Dales/Nidderdale – 10 nests

Northumberland – 9 nests

North Pennines – 7 nests

Peak District – 5 nests

North York Moors – 0 nests

It’s notable, although NE didn’t observe it, that there have been no nests within the North York Moors – the world with the very best dying fee of Hen Harriers from the revealed satellite-tagging examine (see right here).  The North York Moors nonetheless appear out of bounds for Hen Harriers.

It wouldn’t have taken NE a lot effort to annotate the checklist above with what number of profitable nests there have been, and that will have been fairly informative.

I’d be very to listen to whether or not the Duke of Westminster struck fortunate with Hen Harriers ultimately in Bowland – absolutely the birds can’t have shunned his land for one more yr?  However not less than the Bowland AONB now can hold its brand with some satisfaction.

Destiny of tagged birds:  the NE weblog says that six tagged birds have disappeared since their final replace (early March) however then they solely checklist 5 birds, and there do look like 5 of them if one consults the Excel desk whose hyperlink is within the NE weblog publish. These 5 birds are Dru (feminine, tagged 2017, who was predated at her nest), Free (male, tagged 2020, who by no means bred and whose disappearance is the topic of a police investigation in Cumbria), Lydia (tagged 2021, disappeared close to a Goshawk nest (although how the Gos persuaded the tag to cease working is unknown)), Harvey (tagged 2021, topic to a police investigation within the North Pennines) and R1M221 who died of an infection and examined optimistic for fowl flu within the Yorkshire Dales. Dru had a superb innings however the different 4 didn’t breed of their quick lives.

The Hen Harrier which examined for fowl flu is regarding – and I ponder what was the provenance of the opposite Hen Harrier that has been reported as having fowl flu – perhaps it’s a fowl tagged by RSPB, perhaps it was a chick, or perhaps NE have forgotten it. Who is aware of?

Brood-meddling: 13 Hen Harriers ‘fledged’ from brood-meddled nests and 12 of those had been satellite tv for pc tagged – 9 from Yorkshire and three from Cumbria. It’s, maybe, tempting to attempt to assess the fledging success of brood-meddled nests with wild nests, and at first look that appears like it’s 13 fledged chicks from 4 brood-meddled nests (3.25 chicks/nest) in contrast with 116 fledged chicks from 45 wild nests (2.6 chicks/nest) however that isn’t the precise comparability for 2 causes. First, you may solely be a brood-meddled nest when you have chicks or eggs  near hatching, however you is usually a wild nest as quickly as there’s a single egg – thus wild nests are at jeopardy for a lot longer and that must be taken into consideration. To elucidate that additional, if (and it’d or won’t be true) wild nests typically are predated on the early egg stage then they enter the class of failed wild nest, however brood-meddled nests can’t fail at that stage as a result of they must get additional via the season to qualify as brood-meddlable. These knowledge should exist, however they aren’t seen to me, and also you’d must take that into consideration. However in any case, second, every brood-meddled nest is, by definition, one in all a pair of nests shut collectively (that’s what the protocol is) and it’s questionable whether or not the opposite nest must be thought to be a wild nest or in a separate class altogether. If, as an example, perish the thought, as soon as brood-meddled chicks had been eliminated, the opposite nest of the pair tended to fail for some motive, similar to persecution, then these nest failures shouldn’t be ascribed to wild nests, in reality they should be a part of the analysis of brood-meddled nests. You see, it’s a bit difficult – let’s hope that the Steering Group have their heads round all this (perhaps they do, I can’t inform).  On the face of it, and never very surprisingly, brood-meddled nests appear fairly productive. However as we all know, Hen Harriers don’t appear to reside very lengthy.

The survival of satellite-tagged brood-meddled Hen Harriers does look increased (by eye-balling the information – small samples apply) than these of non-brood-meddled tagged birds – that’s fascinating. Why may it’s? It may be as a result of being faraway from the hazard of the moors and introduced up in a cage makes you notably match to outlive as soon as launched once more (potential – however I’m sceptical) or it may be that capturing estates know the place brood-meddled Hen Harriers are and don’t kill them too typically (potential and plausible). Right here once more, the opposite nest  in a pair of Hen Harrier nests, one in all which is brood-meddled, must be used to match survival of intently matched nests – however one can see from the areas of birds tagged every year by NE that isn’t achieved – that’s a disgrace.

If we think about that capturing estates could possibly be extra prone to kill a satellite-tagged Hen Harrier that’s not one of many brood-meddled birds, than one that’s, then that provides some extra complexity. The latter clarification is a little bit of a problem for assessing this trial as a trial however it will probably actually be used as a conservation measure.

With this variety of nesting Hen Harriers I could turn out to be extra relaxed about brood-meddling – though I’m not but. My view has at all times been that brood-meddling must be a reward for good behaviour quite than a reward for unhealthy behaviour, and perhaps we’re getting there.  We’d all have to see a correct evaluation of the information earlier than we may make up our minds about any of this.

What has pushed the rise?:  there may be a lot that’s nonetheless secret or unclear concerning the nesting inhabitants of Hen Harriers in England that it’s tough to evaluate what has gone on. Nevertheless, we are able to make certain that comparatively few broods have been meddled through the years and they aren’t sufficient, at my transient look, to have pushed this enhance on their very own, and I don’t suppose anybody is claiming that they’re (this yr, but).  Certainly, something to do with brood meddling can solely be a small a part of the image.  I ponder how a lot of this very welcome enhance in numbers is because of birds being tolerated in the event that they arrive in spring and lots of of these birds may be heading for Scotland or perhaps even Wales, and might thus be thought to be immigrants.  Relatively than will increase in productiveness, or survival, immigration coupled with larger tolerance on grouse moors would be the driving drive.

Why ought to there be larger tolerance?  There are such a lot of moors with low Crimson Grouse numbers, because of climate and illness primarily, that it actually isn’t price taking the chance of breaking the legislation, and extra Hen Harriers are being allowed to outlive.  As pushed grouse capturing continues to say no then its  affect on Hen Harrier numbers can even decline.  I’d be very to see what would occur in a yr when spring grouse numbers had been excessive and everybody was trying ahead to an enormous season – what number of Hen Harriers will there be then?

It’s enjoyable to invest, however a method or one other, Hen Harrier numbers at the moment are a lot increased than any time in the previous couple of many years. That needs to be excellent news.

 

 

 

 

 

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