Fact Sheets

Sparrowhawks

1. INTRODUCTION

In the late 1950's and early 1960's sparrowhawk numbers fell dramatically. They were reduced by 50% in western Britain and were virtually wiped out in eastern areas. This was mainly due to the increased use of DDT, aldrin and dieldrin as agricultural pesticides. These chemicals accumulate through the food chain and affect the fertility of birds of prey. Legal and voluntary bans on the use of these substances have reversed the situation and now sparrowhawk numbers are recovering. In some areas, they are nearly as common as kestrels, although they behave more secretively and are less noticeable.

2. SPARROWHAWK FEATURES

Both sexes have short, rounded wings and a long tail. The male sparrowhawk is one of the smaller raptors, only weighing 100 - 200gm and has dark grey upper parts, and reddish barred underparts. The female is much larger than the male, and can weigh 180 - 350gm. with greyish brown plumage, and brown bars on the underparts. She has a white stripe above the eye. The male and female are the same length, usually between 30 - 40 cm. The sparrowhawk is well equipped to hunt from the air as its long tail acts as a rudder. The wings are 55 - 70cm. long and are rounded. This is short for a bird of prey, but gives the sparrowhawk more manoeuvrability when flying between the trees of dense woodland.

The sparrowhawk hunts from the air, darting out of cover with great speed to kill its prey. A sparrowhawk does not hover, unlike the kestrel, and relies on speed and surprise to catch its prey. It has long slim legs, large sharp talons and a very sharp hooked beak, for piercing and tearing up prey.

3. HABITAT

The sparrowhawk can be found mainly on farmland, in hedgerows along country lanes, and coniferous and mixed woodland.

4. FOOD AND HUNTING

The sparrowhawk’s main diet is small birds like sparrows, starlings, thrushes, and chaffinch, although it will occasionally take mice, voles and young rabbits. When there is a shortage of food it will even eat insects like beetles. It hunts with great agility, hiding under cover and then launching out at speed to catch the small prey in its talons, whilst it is in flight. Often just the force of the impact kills the prey.

In open country, the sparrowhawk flies low over ground, skimming hedges and fences, but staying close to cover so it can rapidly pounce on its victims. In woodland its agility enables it to fly swiftly between the trunks and branches. The female sparrowhawk, being larger, will often kill bigger birds like the fieldfare and woodpigeon. It carries its prey to a ‘plucking post’ which is usually a fence post or tree stump. It perches there and plucks the prey before eating it. They are very strong birds which can carry prey as heavy as themselves. A sparrowhawk can often be spotted in the fields by the crowd of small birds that gather and mob it in an attempt to drive it away from their nests.

5. BREEDING

Sparrowhawks are solitary birds and only come together to breed during spring and early summer. The female builds the nest that is made up of both green and dry twigs, and most often sited in the branches of a conifer, close to the trunk. Sometimes she will use an old nest of another species as a foundation. She lays between four and six bluish white eggs specked with brown. The eggs are incubated for about 35 days before they hatch. Both parents feed the nestlings for 3 weeks to a month before they leave the nest. The nestlings require a large quantity of food, as each one will eat two or three sparrow-sized birds every day.

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