Raptors of Coombe Bissett Down (Part Two)

Raptors of Coombe Bissett Down (Part Two)

Community Engagement Assistant, Oliver Davies, explores the ecology and behaviour of raptors you might observe during a visit to Coombe Bissett Down, including the sparrowhawk, red kite, and peregrine falcon.

Sparrowhawk (Accipiter nisus)

As our second most common raptor and a frequent garden visitor, the sparrowhawk is often seen single-mindedly chasing down prey and consuming it in its favourite plucking spot. It is a bird specialist found in mixes of woodland and open countryside, and there are 40,000 pairs in the British Isles, which is an astounding number, considering that 80% of its population was wiped out by pesticides in the 50s and 60s. They are now recognised as a valuable indicator of a healthy and diverse bird population. 

The long tail of a sparrowhawk could be confused with that of a kestrel, but the finely barred underparts and furious expression are unique to this raptor – with exception to the considerably larger goshawk. Males are grey on their back and have rusty barring on their chest, whereas females tend to be browner, and their front is a clear white with dense, black barring. They will hunt birds of any size up to their own, as well as small mammals – particularly bank voles. However, female sparrowhawks are 15% larger and two times heavier than males, which means that the latter falls comfortably within the former’s size range of prey. 

In early spring, females will survey their large home ranges for a male that has found and defended a good territory. The pair then perform high, circling flights above their territory with fluffed out tails. A nest is built from scratch each year, and it will be ready by May when the female lays up to 6 eggs and spends the following 34 days incubating them as the male collects food. The chicks then take their first flight around 28 days after hatching and will spend the following 4 weeks receiving dwindling provisions of food from their parents. Some fledglings sneak into other nests to take advantage of extra free meals, but most move on to establish their own territory in time for breeding seasons next spring. 

Red kite (Milvus milvus)

At the start of the 20th century, there were only 5 pairs of red kites remaining in Britain. Once a greatly appreciated city-street cleaner that was as prevalent as pigeons are today, this carrion specialist suffered from endless persecution in the 18th and 19th centuries. Reintroductions started in southern England and northern Scotland in 1990, and now the red kite has reached a population of 1,800 pairs in the British Isles. This raptor is seen in almost any area of open countryside with enough trees for nesting.

Outsized in the UK only by the golden and white-tailed eagles, a red kite can be identified from almost a kilometre away by its characteristic forked tail and long-fingered wings. It is mostly a foxy red-brown colour with black streaks on its front and back, but its head is grey and the underside of its wings are pale with black tips on the very ends. Red kites often join other scavengers on large carcasses, taking away scraps of food to consume elsewhere, but they also feed on roadkill and earthworms.

Red kite pair bonds are monogamous and long lasting, and a couple will stay in their territory all year round. Breeding age is usually 2 years, and they attract a mate by flapping their wings with slow, deep beats, which is an unusual but irresistibly attractive behaviour for a soaring bird. Their nest comprises a messy lump of sticks that is often decorated with plastic bags, bits of fabric, and socks; Shakespeare appropriately quoted in Winter’s Tale, ‘When the kite builds, look to lesser linen’. 40 days of courtship is followed by a month of incubation – mainly by the female – on two or three eggs. The chicks will then take their first flights at two months of age.   

Peregrine Falcon (Falco peregrinus)

People have trained raptors for falconry since the 9th century, but the most esteemed of all the trainable birds of prey – fit for a medieval king – is the peregrine falcon. 1,400 pairs can be found in the British Isles, and although they are most common along the rugged coastlines and craggy uplands of the north east, peregrines are beginning to thrive in urban areas. Many cliff-like buildings have become nesting sites for this iconic bird, including Salisbury Cathedral, which is only 3 miles from Coombe Bissett Down.

At a distance, the peregrine falcon appears almost black and white, but its back is actually a dark grey-blue, and its otherwise white front has fine bars running across it. It is the biggest and most powerful of our British falcons, with a square-tipped tail and pointed wings that curve towards the body like the arms of an anchor. Their flight is fast and showy, but of course, it is their hunting style that captures people’s attention. They are bird hunters, capable of taking down anything between a swift and a goose – buzzards and grey herons have also been reported succumbing to the claws of this raptor. After circling high above its chosen quarry, the peregrine falcon plunges into a headlong dive, reaching speeds of over 200mph where it then delivers a high-velocity punch that dispatches its prey almost instantly. In our cities, they have become a greatly appreciated predator of feral pigeons and black-headed gulls.

Peregrine falcons stay together season after season, but they always roost in separate places over winter before returning to their previously established nesting site. Much of their courtship comprises cooperative hunting, but males will also perform dives and provide food for the female to win her favour. Their nest is nothing more than a bare scrape, onto which the female lays three or four eggs in early April, and she will incubate the eggs for a month. When the chicks have reached six weeks of age, they leave the nest and take up residence in nearby feeding posts where they continue to play together and receive food from parents for a couple of months. These younglings then begin to make their own kills and disperse before winter to find their own territories.