One of our readers, Peter Greenhill of Narborough, recently saw this female Sparrowhawk take a Woodpigeon in his back garden. It is never pleasant to witness the life and death struggles that routinely take place, but as Peter pointed out we have to accept that these events occur just as much in our local villages as on the plains of Africa. Woodpigeons are doing really well at the present time with an estimated 5 million pairs breeding in the UK. Sparrowhawk numbers, in contrast, fell dramatically in the last century, becoming extinct in many English counties. Numbers have now climbed to around 30,000 pairs in the UK and they are no longer considered to be under threat. They eat mostly small birds, with males taking birds up to the size of a Blackbird whilst the larger females can catch birds up to pigeon size.
Dramatic encounters such as this are very rare events in most gardens, but on a smaller scale the struggles between predators and prey are taking place constantly. If you have a garden pond you may have noticed Pondskaters, small insects that skate around on the surface of the water. They are predatory bugs, 1 – 2 cm in length, that feed on flies and other small insects that fall into the water. The Pondskaters are attracted by the vibrations given off by the fallen insects and several can cluster around the prey, as shown in this photograph. In gruesome fashion, they all stab the prey with their sharp mouthparts thus recycling all of the nutrients rather than letting the remains rot in the pond. Their long legs and water-repellant feet allow them to skate around without sinking.
I noticed another example of predation in my garden last month. Red Campions are delightful little pink flowers, but they are soon infested with Campion Aphids – small black bugs that suck the sap from the upper stems. These infestations occur very rapidly and there are soon many hundreds of the bugs present. However, the predators now rush to the rescue with ladybirds (including this delightful little 14-spot Ladybird) making a meal of the aphids. They are soon joined by ladybird larvae and hoverfly larvae that also survive mostly on aphids and within a week or so all of the aphids had been eaten.
Predators play a key role in maintaining the natural balance of ecosystems, with both predators and prey benefiting from this interaction. Predators cannot be eliminated without risking the balance of the larger ecosystem, resulting in an overabundance of prey species. As I described above with the Red Campion, an ecosystem with lots of predators available will usually take care of any pest species. The use of pesticides will temporarily remove the pests, but will also kill all of the predatory species so when the aphids return there will be no natural control, thus requiring the unnecessary application of more toxic chemicals. Much better to leave nature to it.
One of our readers, Peter Greenhill of Narborough, recently saw this female Sparrowhawk take a Woodpigeon in his back garden. It is never pleasant to witness the life and death struggles that routinely take place, but as Peter pointed out we have to accept that these events occur just as much in our local villages as on the plains of Africa. Woodpigeons are doing really well at the present time with an estimated 5 million pairs breeding in the UK. Sparrowhawk numbers, in contrast, fell dramatically in the last century, becoming extinct in many English counties. Numbers have now climbed to around 30,000 pairs in the UK and they are no longer considered to be under threat. They eat mostly small birds, with males taking birds up to the size of a Blackbird whilst the larger females can catch birds up to pigeon size.
Dramatic encounters such as this are very rare events in most gardens, but on a smaller scale the struggles between predators and prey are taking place constantly. If you have a garden pond you may have noticed Pondskaters, small insects that skate around on the surface of the water. They are predatory bugs, 1 – 2 cm in length, that feed on flies and other small insects that fall into the water. The Pondskaters are attracted by the vibrations given off by the fallen insects and several can cluster around the prey, as shown in this photograph. In gruesome fashion, they all stab the prey with their sharp mouthparts thus recycling all of the nutrients rather than letting the remains rot in the pond. Their long legs and water-repellant feet allow them to skate around without sinking.
I noticed another example of predation in my garden last month. Red Campions are delightful little pink flowers, but they are soon infested with Campion Aphids – small black bugs that suck the sap from the upper stems. These infestations occur very rapidly and there are soon many hundreds of the bugs present. However, the predators now rush to the rescue with ladybirds (including this delightful little 14-spot Ladybird) making a meal of the aphids. They are soon joined by ladybird larvae and hoverfly larvae that also survive mostly on aphids and within a week or so all of the aphids had been eaten.
Predators play a key role in maintaining the natural balance of ecosystems, with both predators and prey benefiting from this interaction. Predators cannot be eliminated without risking the balance of the larger ecosystem, resulting in an overabundance of prey species. As I described above with the Red Campion, an ecosystem with lots of predators available will usually take care of any pest species. The use of pesticides will temporarily remove the pests, but will also kill all of the predatory species so when the aphids return there will be no natural control, thus requiring the unnecessary application of more toxic chemicals. Much better to leave nature to it.
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