A pair of sparrowhawks has been seen hunting in the park.
Sparrowhawks (Accipiter nisus) prey upon birds; they are specialists, adapted to hunting in the confines of woodland, and have been recorded preying on more than 120 different bird species, all the way from tiny goldcrests to pheasants. If you find scattered feathers where a great tit or a pigeon has been killed, the killer might well be one of this pair of sparrowhawks.
 Male sparrowhawk by John Purvis (CC BY-NC-SA 2.0) flickr.com  Female sparrowhawk by Peter Trimming (CC BY-SA 2.0) geograph.org.uk
The female is 25% larger and heavier than the male and can tackle much larger prey: pigeons, thrushes or even one of our ever increasing population of magpies. The male is smaller and more inclined to prey upon tits, finches and sparrows.
Sparrowhawks tend to kill very young birds or the sick, old, injured and weak. They keep the populations of their prey species healthy. During these summer months almost half of the pair’s diet will be fledglings; of the fledglings that survive the sparrowhawks’ attentions this summer, a high proportion will die of starvation during their first winter. The number that will survive to breed next year will be unchanged by the presence of these predators.
Contrary to popular belief, sparrowhawks do not control the numbers of their prey, but the numbers of prey do control the number of sparrowhawks. If this pair leaves, there will be no obvious increase in songbird numbers, nor will there be an obvious decline if the hawks return. But if, for some reason, our songbird numbers decline, the sparrowhawks will be forced to leave.
Sparrowhawks are the very definition of an apex predator and their presence in the park is a tribute to its biodiversity.
Header picture: Sparrowhawk in flight by Mark Kilner (CC BY-NC-SA 2.0) flickr.com
A version of this post was first published in July of 2020