Sparrowhawk - January 2022
Even though Sparrowhawks are our second most common bird of prey (around 40,100 breeding pairs in the UK and increasing) they fly among us largely unseen, because rather than hanging around where we can see them, such as above road verges, they skulk in the shadows of dense cover, in hedgerows and woodlands. With their increasing population and shrinking habitat, they are found more and more in our gardens. Where we often make it easy for them to hunt, with bushy garden shrubs and bird feeders attracting their prey. Having an apex predator like a Sparrowhawk visit your garden is thrilling and shows that you have managed to attract a healthy population of garden birds and rest assured the overall population of small garden birds is not significantly affecting by Sparrowhawks, if you want to worry about any of their predators, worry about domestic cats!
Sparrowhawks are small birds of prey, they have long tail feathers and short rounded wings, with a wingspan of 55-70cm. Designed for high manoeuvrability, allowing them to fly between trees and small spaces at speed in short sharp hunting bursts. Typically only about one attack in ten results in capture, most of their diet is made up of small birds, males can catch birds up to thrush size, but females, being bigger, can catch birds up to pigeon size. In order to be successful when they hunt, they first have to be able to approach their prey closely and undetected, relying on the element of surprise. Right now is the best time for us to see them but also a difficult time for them to hunt, as the lack of leaves reveals their hidden world, Sparrowhawks will often follow a regular route to get close to potential prey.
Interestingly the colour of a Sparrowhawk’s eye depends on its age and gender. Typically younger birds have greenish-yellow eyes which become brighter yellow within the first couple of years of their life. In some older Sparrowhawks, the eye colour can become orange or even occasionally, red! Sparrowhawks have thin yellow legs and the colour of their plumage depends on their age and sex. Adult males have slate-grey (often appearing blue) upper parts and fine rufous barring underneath. Females have brownish-grey upper parts and less barring than the male. They also have a more prominent white line above the eye. But the sure way to tell the sexes apart is their size; female Sparrowhawks are typically 25% larger than males, but can be twice as heavy!
In medieval falconry, birds of prey were trained for sport. Falconry was distinguished from hawking, falconry was practised from horseback and hawking by foot. Whilst the King was expected to fly a Gym falcon and the servant of knave a Kestrel, the Sparrowhawk was deemed to be a bird for a priest.
In more recent times the Sparrowhawks were virtually wipes out. By the 1960s, the liberal use of the pesticide DDT had left the Sparrowhawks rare. Like all birds of prey, they are extremely vulnerable to pesticide poisoning, which has the effect of either killing them outright or rendering them infertile.
Our British Sparrowhawks are largely resident, and don’t travel very far in their whole lives. Most of them will breed within 12 miles of where they were born. Birds which use the same nesting territory in successive years will usually also have the same mate, until one of them die and it is usually the male that goes first. He will do well to live to seven or eight, whilst the female may survive until she is ten or 11. Breeding pairs will not tolerate another Sparrowhawk in their territory, the size of which is entirely dependent on the availability of food, it can be from 0.25 up to 1.25 miles. Three to six eggs are laid at two-day intervals during May. 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.