Sparrowhawk Special - The Raptor Debate
During the 1960's when as a child my keen interest in natural history was developing the only birds of prey I regularly encountered were Kestrels and owls. Common Buzzards were pretty much confined to western Britain, the only Marsh Harriers were at Minsmere and Red Kites and Ospreys were something I could only dream about. The other notable absentee was the Sparrowhawk whose population had been decimated by toxic pesticide use and was confined to extensive forests and wilderness areas where pesticides were less frequently used. Even here they were rigorously persecuted by foresters and gamekeepers.
Nowadays, our better educated and more enlightened attitudes, coupled with the banning of most toxic pesticides, has allowed a slow recovery of many of our raptor species, both diurnal and nocturnal. Common Buzzards now breed in many south Lincolnshire woodlands and the Hobbies can be seen in Rippingale most summers. There are also many pairs of Marsh Harriers breeding along the Lincolnshire coast and fens. The bird of prey that still causes the most controversy, though is, without doubt, the Sparrowhawk.. Of all the birds of prey the Sparrowhawk is the one we are most likely to see in our gardens and typically, our encounters can be emotional experiences that will leave us with mixed feelings.
Many of us will spend considerable time and money feeding the birds in our garden and the experience of witnessing a Sparrowhawk taking a Blue Tit or Goldfinch from our bird feeders can be quite distressing.
Some like one ill informed fellow resident of Rippingale, might be tempted to tilt the balance in favour of our song birds, as he did, by shooting one of the only pair resident in Rippingale during the nesting season. This almost certainly resulted in the young Sparrowhawks starving in their nest, but his action is unlikely to have increased the song bird population at all.
Most bird populations are governed by the availability of food, suitable habitat and weather conditions and this applies equally to Sparrowhawks and Blue Tits. In a good year when plenty of caterpillars are available Blue Tits will raise several broods and a brood size could be as high as 16! If all these young birds survived to adulthood there would be insufficient nest sites and food shortages might well result in the extinction of some of their insect prey species. So nature has its natural controls to check the populations of all species; for some caterpillars it might be Blue Tits and for Blue Tits the Sparrowhawk certainly has a role to play.
In point of fact the domestic cat poses a greater threat to song birds and the combined population takes more garden birds than Sparrowhawks. We had one pair of Sparrowhawks in Rippingale but how many cats?
Sparrowhawks are strictly territorial and one of the factors that governs the size of the territory is the availability of prey. A resident pair of Sparrowhawks will not tolerate other Sparrowhawks in their territory and I have often seen resident birds driving off intruders. In fact Sparrowhawks are pretty intolerant to other species of raptors too and will often drive off much larger species such as Buzzards. Furthermore, a pair of Sparrowhawks are perfectly engineered so that they do not compete with each other for the same food within their territory. The female is much larger than the male and tends to feed on much larger birds. I have seen our local female Sparrowhawk taking adult Collared Doves for example. The much smaller male has to confine his tastes to smaller species and thus does not compete directly with his mate.
To end this article on a positive note a pair of Sparrowhawks near my Sleaford office have successfully reared two young, who are still fairly inept hunters, but are getting plenty of practice chasing the resident pigeons and doves. Elsewhere Red Kites have nested for the first time in Lincolnshire and Marsh Harriers have raised young only a few miles from Rippingale.
All in all the future looks bright for our raptors, providing we humans can resist the temptation to interfere with nature's delicate balance.
Some text may be lost if you are viewing with a low screen resolution - click here for more info