Thursday, 17 July 2014

Hen Harriers suffer major losses to predators

This is the time of year when young Hen Harriers are beginning to fledge. What a joyful time and what an uplifting experience to see these youngsters, with their dark chocolate brown backs and cinnamon underparts, twist and turn playfully at one another as they wait for their mom or dad to return with food. Up they'll rise and take the food in the air, just like the specatcular food passes from the male to the female earlier in the breeding season. It truly is a sight to behold and treasure.

However, each year it is becoming more and more apparent that the parents are finding it next to impossible to rear their chicks to the stage that they can fledge. Every year, the majority of nests fail. This means every following year, there are less Hen Harriers and a number of areas are now devoid of Hen Harriers. Where will it end?

One of the main causes of nest 'failure' is predation. Fox, Mink, Pine Marten, Hooded Crow and Magpie are seen as the key species involved. The change from open moorland and extensive farmland to forestry in many of the Hen Harrier areas has benefited those predators and put rare breeding birds like Hen Harriers, Curlew, Red Grouse etc. at a major disadvantage. Not just a disadvantage in the case of Hen Harriers -in fact a death trap. If a female harrier nests in young forestry because of the tall vegetation that grows between the trees (sometimes this is the only potential nesting habitat given it was planted on a bog they would have naturally used) there is a good chance she is in a precarious situation, surrounded by predators with very good noses. This is what is called an Ecological Trap.

3 comments:

  1. Add man to the list and they don't stand a chance.

    ReplyDelete
  2. Of the predators that you have listed above the fox, mink and magpie are well established in open countryside. The pine marten population is not huge as far as I know. Heavy woodland results in less human interference. It`s hard to know which type of nesting site would be worse.

    ReplyDelete
  3. Hi Mike and Tony,

    Thanks for your comments. Pine Martens (a protected native species) are doing well in places, which is great news. However the scales seem to be tipped against ground nesting birds like the Hen Harriers that could otherwise withstand a certain amount of nest loss.

    As regards heavily planted areas being safer from humans - one would need to consider whether such isolation might even facilitate serrupticious activity like persecution? These forests are being used for a number of other illegal activities from dumping to unlicenced rallies to worse.

    ReplyDelete