Male Hen Harrier (Circus cyaneus) Photo By Isle of Man Government – Hen Harrier, CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=30598443
Dear Readers, of all the UK birds that I want to see and have never seen, the hen harrier is in the top five. A bird of moorlands, bogs, marshes and other wild, open country, it has seen a shocking decline in England and Scotland over the years, though it seems to be doing relatively well in Wales, where there are 40-60 breeding pairs. There are two main reasons for its decline. The first is forestry – many areas of lowland have been, and were, planted with Sitka spruce, destroying the habitat for these birds which, unusually for birds of prey, nest on the ground.
However, the main cause is human persecution. The clue is in the name: hen harriers largely eat birds (with meadow pipits being a particular favourite), though they will also eat frogs, voles and insects. Gamekeepers see them as being a danger to the red grouse on driven grouse moors in England and Scotland, and the mere presence of a hen harrier is believed to impact a day’s grouse shooting. Literally hundreds of these birds are illegally killed every year. English moors should provide habitat for more than 300 pairs of the species, but in some years none have bred at all. It appears that in some areas grouse shooting is only viable if the animals that prey on the grouse are killed, which in my view means that it isn’t viable at all. Raptor Persecution UK is keeping track of all the hen harriers and other birds of prey that simply ‘disappear’ close to grouse moors. Their latest report makes for grim reading.
Female Hen Harrier (Photo By Dibyendu Ash, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=45878145)
Hen harriers are elegant birds who hunt by sight and by sound – note the owl-like facial disc in the photo of the female above, which helps to channel the tiny scurrying sounds of mice and voles. During the breeding season, the male will drop food to the brooding female, who will catch it in mid-air. Hen harriers practice polygyny, with the males mating with up to five females. This means that they have to catch an awful lot of meadow pipits and voles, and research in Orkney showed that the more food is available, the more mates a male will have.
In the winter hen harriers will roost communally (if there are enough of them), and birds from Scandinavia and northern Europe may be spotted on salt marshes and other coastal areas right around the UK and Ireland. There is a famous population on the Isle of Man, and, as previously mentioned, on Orkney.
Hen Harrier from the Crossley ID Guide (Richard Crossley, CC BY-SA 3.0 <https://creativecommons.org/licenses/by-sa/3.0>, via Wikimedia Commons)
Perhaps most extraordinary of all, though, is the ‘sky dance’ display that the male hen harrier performs to attract a mate. Twisting and tumbling in the air, almost out of control and then regaining control, this unfortunately also makes the male bird extremely obvious and vulnerable to those who would seek to eliminate it. But to watch the display is to see something unforgettable. Have a look at the video below, and you’ll see what I mean.
I am familiar with the mating displays of some of our raptors, but dropping food to females in mid-flight is new to me – how fascinating.
Peregrines do this too, I actually saw them doing this a while back when they nested above the Royal Courts of Justice 🙂