Girton Birdwatch - February 2007
Although we are often alerted to the presence of a nearby Sparrowhawk by the fearful scattering of the other local birds I must admit to having felt envious when villagers and friends have reported the close-up views they have enjoyed of this handsome hawk either perched in their garden bushes (J.C.) or bathing in their pond (N. and J. Knights). This lack was remedied the other day when my wife Janet drew attention to an 'odd' bird, which she at first took to be a collared dove, sitting quietly amongst our birdfeeders, a mere 15 feet from our kitchen window. It turned out to be a male Sparrowhawk and through the binoculars it was possible to appreciate its glorious mixture of rusty orange cheeks and throat, barred chest and deep slatey-blue back. The female, as with most hawks and falcons, is larger than the male and lacks the rufous coloration and has a brownish grey, rather than blue, back. Moreover, the sexes exhibit the largest size difference of any British raptor with the female up to twenty-five percent larger than the male and about twice as heavy. The male seldom weighs more than 5 ounces (150gm), a true flyweight amongst our birds of prey (What about the Merlin? I hear you ask; but more of that later). This, of course, means that the female is capable of targeting a broader range of prey, although the male is capable of tackling birds as large as himself. I know that there are mixed views about Sparrowhawks but I like to see them and, as I've said before, their increasing presence is a good indication of the health of our environment and the bird's recovery after the depredations of organochlorine pesticides. However, it does eat a lot of small birds! In the late 1970's a study by Leslie Brown indicated that the amount of food a Sparrowhawk pair and their brood required during the year was substantial, and that to achieve the 66 lb (30 kg) of food killed per adult per year and the 44 lb (20 kg) eaten, more or less 800 average sized or 1,600 small birds needed to be killed each year. For the three months that a brood of two is fed another 400 small birds are needed. One might expect, then, that the 3,600 birds taken would make serious inroads into local populations, but other evidence from studies of small bird populations apparently indicates that Great and Blue tits, for example, are no less common when Sparrowhawks are about than when they are absent. Many of the birds fed to the young are young themselves, and tits have large broods, and it is clear that many of those caught at any time are the older, less well fed, or less fit, than those which manage to escape.
The reason I mentioned the Merlin is that one of these small falcons was seen by the owners of the Oakington Garden Centre while they were out walking over Christmas/New Year. This bird is, in fact, our smallest sized falcon although not our lightest; that distinction belonging to the male Sparrowhawk. It is only 10-12 inches (25-30 cm) long compared with the 12-16 inches (30-40 cm) range of the Sparrowhawk. That makes it shorter than a Mistle thrush. The male is grey above and a rusty yellow underneath, with long dark streaks. The female has larger streaks below and is dark brown above, with a barred tail; that of the male is not so deeply barred. This is a bird more normally associated with moorland, where it preys on Meadow pipits, Twite, Ring ouzels etc, than with our flat and intensively cultivated environment. However, it is well-known that in the winter the bird migrates to the coast or to the familiar Washes of this region, but no one appears to be sure why. So keep your eyes open. I have only seen the one, and that was in the Isles of Scilly. It is a very fierce and energetic bird, which seldom stays still, and launches low level sorties at prey involving light, deft wing-beats interspersed with glides. Should it 'stoop' upon prey, closing its wings completely and diving, it turns into a deadly missile, the speed and ferocity of its attack allowing it to down birds four times its own weight. Its name has no connection with the magician of the King Arthur legends but comes from the old French name for the species: esmerillion.
It is pleasing to report that we still have Barn owls around the village. Rosie Sykes saw one quartering the field between the George, Old Crown and Golf Club while waiting for an early morning bus on 15th December. She has seen Muntjac deer in the same field also. It is quite an achievement to see a Muntjac because they are very secretive and good at concealment, but there are lots around the village as their many sharp, v-shaped tracks testify. It is also a truly tiny animal (with small unbranched antlers), which aids its concealment. It is not a native but is believed to have escaped from the Duke of Bedford's estate at Woburn, where it was brought first in 1894.
Ken Sheard, Ken.sheard2 at ntlworld.com