Q: How many hen harriers are there in the UK?
A: There are 630 hen harrier pairs in the UK.
Q: How many hen harriers are there in England?
A: Hen harriers don’t stay within the borders of countries so it depends when in the year you count them. England also has higher numbers of harriers during migration and in the winter, when harriers visit from Scotland and continental Europe. Counts are not made of how many stay all year in England, but there are believed to be at least 12 pairs.
Q: How many hen harriers could settle in England and not affect land management?
A: The Environment Council harrier mediation process modelled how many harriers could settle and not affect land management. Given a crude estimate of the area of suitable habitat, a sustainable number could be 82 pairs of hen harriers in England.
Q: You say ‘suitable habitat’ – how much of that is on grouse moors in England?
A: 50% of the suitable English habitat is found on grouse moors – so there could be up to 41 pairs on English grouse moors.
Q: Why are there so few hen harriers on the 50% of suitable habitat in England that has no driven grouse shooting?
A: It is likely to be a combination of harrier nests being predated, lack of food, persecution, disturbance, and possibly failing to have enough birds settled in an area to make it attractive to others. A paper published in 2013 identified that hen harriers benefited from the control of predators, such as foxes and crows, by gamekeepers to protect red grouse. Another paper published in 2014 noted that over half the hen harrier breeding attempts on Skye failed due to predation. More research is needed.
Q: Why are there so few hen harriers on English driven grouse moors?
A: In addition to the reasons above, the harrier-grouse conflict can make moorland management uneconomic. Hen harriers eat grouse. If there are enough to make a shoot uneconomic, the gamekeepers lose their jobs, and numbers of ground-nesting birds decline, including ones of conservation concern such as waders. The Joint Raptor Study (1992-1996) and subsequent studies at Langholm demonstrated that this situation can really happen, and is no exaggeration.
Q: So what happened at Langholm?
A: Between 1992 and 1997, hen harrier numbers rose from 2 to 20 pairs in 6 years on a driven grouse moor. Shooting was abandoned because the hen harriers ate over a third of all grouse chicks that hatched. With no grouse shooting, the local culture, economy and employment suffered and the control of generalist predators ceased. By 2003, 20 harrier nests were back down to 2 and numbers of breeding grouse and waders had more than halved. Predation was identified as the most likely cause of the declines. Grouse moor managers felt their worst fears had just been proven – this was a real lose/lose situation.