The hen harrier is a predatory bird species that lives over a wide region including parts of Asia, Europe, and North America. These birds generally stick to the northern parts of their range in the summer, and they will migrate south in the winter. On average, the birds are about 20-inches (50 cm) long, and weigh about 15 ounces (425 grams), with a wingspan of 4 feet (1.2 meters). The female hen harrier has a bigger body than the male, and both sexes look very different, with males being mostly gray, while females are mostly brown. Both varieties have broad-looking faces with hooked beaks, which makes them look somewhat owl-like.
These birds are a kind of hawk, and they hunt many different rodents and other small animals. They also hunt and catch many other bird species. The hen harriers have excellent vision and hearing, which they use to spot their prey from the sky and zero in before diving. The broad face shape gives them an ability that is similar to an owl’s sound-based directional navigational skill.
Hen harriers generally spend a lot of their time in flat grassy areas. This would include places like pastures. These kinds of areas are good for them because the ground is easy to see from the sky, which can potentially simplify hunting. They are fairly social birds and often live in large groups. Sometimes the groups can include other predatory bird species.
When breeding, the hen harrier male has a courtship display. He will fly up and down, diving repeatedly while turning in a corkscrew pattern. Males have long-term commitments to more than one female that they mate and reproduce with every year.
The average clutch is approximately five eggs. It takes about 30 days for the eggs to incubate, with the female doing all the work in that area. The males go out and hunt for the females while they stay with the eggs, and they actually drop the food from the sky as they pass over the nest area. Once the chicks are born, they will leave the nest after about five weeks.
These birds aren’t endangered, but their population has been going downhill. Some of this is due to things like habitat loss, but they are also hunted. In Britain, the hen harrier hunts the grouse, which is also a very popular game bird. Some gamekeepers kill harriers to make sure that they don’t over-hunt the grouse. This activity has greatly reduced their population in Britain, and some efforts have been undertaken to try and reverse the situation.