Sparrowhawk – Accipiter nisus

The Sparrowhawk is a relatively small birds of prey adapted for hunting smaller birds in confined spaces like dense woodland, so gardens are ideal hunting grounds for them. Adult male sparrowhawks have bluish-grey back and wings and orangey-brown bars on their chest and belly. Females and young birds have brown back and wings, and brown bars underneath. Sparrowhawks have bright yellow or orangey eyes, long, yellow legs and long talons. As with most birds of prey the females are larger than males.

Habits and habitation

Sparrowhawks breed in woodland but also visit gardens and more open country. They can be seen in towns and cities, as well as rural areas. Listen for the alarm calls of smaller birds as they spot a sparrowhawk and will alert other birds in the area to the danger. In the UK sparrowhawks are found everywhere, except for parts of the Scottish Highlands, the Western Isles and Shetland.

Reproduction

Their territories are well spaced – pairs do not tolerate another nest close by. The distance between each nest varies ranges from 0.5 km to 2.1 km. This is determined by the local food supply – the better the food supply, the smaller each territory will be. The nest is usually built in lower parts of the canopy, close to the trunk of a tree and usually concealed from view. It is a sturdy platform of twigs, lined with bark flakes. A central ‘cup’ prevents the eggs from rolling out. Nest building can take several weeks and is often completed long before the eggs are laid.

Sparrowhawk facts; Because of the size difference, male sparrowhawks court the females with caution, as the female can (and sometimes does) kill her suitor.

Sparrowhawk chicks hatch when there are plenty of fledgling small birds around, in the same way that blue tits synchronise their breeding to coincide with the peak availability of caterpillars. Three to six eggs are laid at two-day intervals during May. Incubation lasts for 32-35 days and the eggs hatch in succession over two or more days, so that the chicks are different sizes. The female helps the chicks to break out of their shell. They are covered in pure white short down, and their eyes are already partly open when they hatch.  Succesive hatching is an adaptation to cope with an unpredictable food supply. If food is short, the youngest chick will die and reduce the brood to a manageable size.

The chicks are very vulnerable in the first week of their lives as they cannot control their body temperature. They are therefore brooded almost constantly at this time, and then progressively less until they are able to do so. The female has sole care of the eggs and young, while the males’ role (from egg-laying through to fledging) is to provide all food required by the female and the chicks. The female will hunt as the chicks get older, but only if the male is unable to catch adequate food by himself.

Diet and feeding

A Sparrowhawks diet mainly consists of small birds and the occasional rodent. 120 different species of prey have been recorded. Males can catch birds up to thrush size, but females, being bigger, can catch birds up to pigeon size. Some sparrowhawks have adapted their hunting habits to catch bats.

Sparrowhawk facts; Their usual flying speed is around 30-40 kph, but a sparrowhawk is capable of up to 50 kph in short bursts.

There have been concerns in the past that sparrowhawks eat too many small birds and cause their population to fall or even become extinct, however long-term scientific studies have shown that sparrowhawks generally have no or little impact on songbird populations. It is worth remembering that sparrowhawks and songbirds have existed side by side for thousands of years without any detrimental effect on songbird numbers.

Conservation Status

The Sparrowhawk , along with other British birds of prey was first given legal protection in 1961.It is now protect in law by the the Wildlife and Countryside act 1981 , which offers protection for the birds , nest sites and eggs. It is estimated that there are 30,000 breading pairs here in the U.K. The Sparrowhawks currently listed as Amber on the at risk list.

The average lifespan for a sparrowhawk is 2.7 years, and very few live longer than seven years. About one third of the adults die each year, and around two-thirds of the fledged young die in their first year, the most common cause being starvation. Food availability and the quality of parental care are critical factors influencing a sparrowhawk’s survival. Lack of food also limits the production of young, just half of sparrowhawk nests produce young in any breeding season. The rate of death among young sparrowhawks peaks in August and September, but adult mortality is at its highest in March and April when food supply is at its lowest. Prolonged hard winter weather can cause a significant drop in the subsequent breeding population.

Sparrow Hawk facts

Length.                    28-38cm

Wingspan.              56-78cm

Weight                     Male        110-180g

                                 Female.   185-345g

Breading pairs.      Approx.    30,000

Average life.           2-3 years

Status.                     Amber

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