An unsteady return

The first National Survey, in 1989, estimated between 578 and 700 breeding pairs in Britain and the Isle of Man. In 1998, there were 570 territorial pairs. By 2004, there was a 41% increase to 806 pairs – the highest numbers of harriers in Britain for over a century. By 2010, the latest survey uncovered an 18% decline, to our current population, give or take, of 662 breeding pairs. Right now, there are more harriers in Britain than the late 19th Century and more than 20 years ago, but fewer than 10 years ago. According to the BTO’S review ‘Hen Harrier population information’, “Hen Harrier distribution appears to have been broadly stable during the past 20 years; overall, breeding occupancy at the 10km scale has increased by 29% over the past 40 years”. At the same time, relative abundance has declined across most of Scotland and England. Harriers do not face British extinction – but they are not recolonising much of Britain. In many cases, numbers are also suppressed where birds do still nest. To see what’s happening, we need to look first at range. In the latest survey, 76%, or 505 pairs, were in Scotland and Isle of Man. There were 59 pairs in Northern Ireland, 57 pairs in Wales, 29 on the Isle of Man but just 12 in England. This last number has fallen since, with zero breeding pairs in 2014. Key refuges for harriers remain those last outposts – Orkney, the Uists, Inner Hebrides and Arran – and expansion has occurred in areas of true wilderness or deer estates, such as north and west Highland and Argyll, with decreases in south and east Scotland. Between 2004 and 2010, the last survey shows a 49% drop in the Isle of Man population, a drop of between 24% and 49% across mainland Scotland, and a 33% increase in Wales. We’ll get to grouse moors in a minute, but let’s look first at what’s limited harriers on the fringes of their range – the refuges that grouse shooting can’t reach.