The Sarrowhawk is arguably the most exciting of all the birds which visit our gardens, and is now a much more common sight having gone through a large population decline over many centuries – but especially during the 1950s and 60s. The female bird is larger than the male, and is brown on the back and wings, with brown bars on its pale underside and breast. The male has a bluish-grey back and wings, and more of an orange-brown colour to the bars on its underside and breast.
Sparrowhawk diet and food
The diet is almost exclusively birds, though occasionally bats may also be taken. As female Sparrowhawks are larger than males, they’re able to prey on larger birds and can even kill something up to the size of a Wood Pigeon. The male bird’s limit is up to the size of a Mistle Thrush, though for both male and female birds they’re likely to take smaller birds than the examples here. Added to which, there is no preference for a particular species of prey, with whatever is available, most numerous and easy to catch being the first choice – hence why finches are often targeted on garden bird feeders. During the songbird fledgeling season, around 40% of the Sparrowhawk’s diet is made of young birds.
Sparrowhawk nesting and breeding habits
The male Sparrowhawk does much of the nest building, which is located in the fork of a tree or on the base of a branch against the trunk, with a preference for conifers. The nest is usually fairly high in the canopy and hidden from view, and consists of a strong platform of twigs and sometimes also lined with flakes of bark. There is one brood of 3-6 eggs with the female incubating them alone, then also brooding the young birds after they hatch until they’re old enough to maintain their own body temperature. During all of this time, the male bird provides the food for both the female and young.
Behaviour traits of Sparrowhawks
Sparrowhawks are a fantastic bird to observe, with their hunting behaviour often appearing to border on lunacy as they take huge risks when manoeuvring between trees and other obstacles in order to catch prey. As part of this and in the early stage of the hunt, a Sparrowhawk will attempt to approach its target out-of-sight, and therefore will use the cover of buildings, hedgerows, undulations in the ground level etc. to get as close as possible before making a final lunge – and all of this at speeds of up to 50kph. Despite all of this effort, it’s likely that only one about one in ten attacks are successful and result in a kill.
Sparrowhawk history and population trends
As a species which is dependent on woodland, deforestation in the British Isles over many millennia will have greatly reduced the population. However, persecution from gamekeepers from the 1840s (when guns became sufficiently efficient to make a negative difference) right up until 1961 when the species gained legal protection, further reduced the population. And a degree of illegal persecution still, sadly, takes place to this day. In addition to this, the use of DDT pesticides in the 1950s and 60s lead to a further dramatic decrease in the Sparrowhawk population, with the effects of the poison in the food chain leading to infertility and a thinning of egg shells which then either a) meant the developing chick died of cold, or b) the egg was broken by the female brooding. The good news is though that, with DDT banned and out of the food chain, the population has bounced back strongly from the mid-1970s onwards, though has levelled out somewhat since the mid-1990s.