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#196
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Lack of invertebrates / house sparrows (was Reed Buntings)
SNIP Birds nesting in my eaves observed using an oscilloscope. They're clever little buggers aren't they? I saw the blackbirds in our garden recently assembling an electron microscope. I reckon the magpies thieved it for them. Steve |
#197
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Lack of invertebrates / house sparrows (was Reed Buntings)
"Tumbleweed" wrote in message . .. "W K" wrote in message ... "Oz" wrote in message news Tumbleweed writes ISTR reading a few years ago that the number of sparrow hawks had risen hugely since the 1940's, maybe to 50,000 or more, whereas 60 years ago or so they were persecuted and very few and far between. If the difference was say, 40,000 sparrowhawks between then and now, and they each ate 1 sparrow a day, that would be 14 million less sparrows a year. Plus, every day I see loads of magpies (probably 10 or 20), which I believe eat other birds eggs. When I was a kid I don't think I ever saw one. I would guess the number of magpies must have risen 10 fold in the last 30-40 years. That must account for a fair few sparrows (and similar) as well. Certainly there are lots of aphids and the like in my garden in the summer and I would have said that most gardeners nowadays used less chemicals than 30 years ago. You certainly cant have a rise in the number of predators and expect the prey to remain constant, You can, if the predation is not the main thing controlling the prey numbers. If the limiting factor is breeding sites and food sources in winter, the ones eaten will just leave more resources for the others and the population level stays precisely the same. after all isn't that the point of all this organic gardening we hear about, encouraging predators such as hoverfly and ladybirds into gardens? If that works for them, I don't see why it wouldn't work for sparrow hawks/ sparrows as well. How do you do that encouragement? Are you bringing/attracting these creatures in from elsewhere? I believe one trick would be to attract more insects in general so that there is a wide selection of prey for them. It would certainly work on a local level if you set up your garden to be an ideal killing zone for the sparrowhawk - but that would probably not effect the overall populations averaged out over the sparrowhawk's range. An equivalent might be to feed a predator and keep its level at higher levels (ie domestic cats, corvids given sources of carrion that help them get through winter in greater numbers) This is nothing like the case with the sparrowhawks (although perhaps all those well fed tits could make a minor difference through the winter). "I don't see" Glad to see such an admission of cluenessness OK, so if you're so clued up, give us the benefit of your all-knowing wisdom, or do you just do poor sarcasm? With that level of radio2 lunchtime ramblings I'd have thought it wasn't worth it. Its about reaching levels of year-round semi-equilibrium, and what the limiting factors are. Sparrowhawks are unlikely to overexploit their area and cause population crashes. (and you know, they eat lots of birds that are having no problems at all, or increasing). |
#198
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Lack of invertebrates / house sparrows (was Reed Buntings)
"Tumbleweed" wrote in message . .. "W K" wrote in message ... "Oz" wrote in message news Tumbleweed writes ISTR reading a few years ago that the number of sparrow hawks had risen hugely since the 1940's, maybe to 50,000 or more, whereas 60 years ago or so they were persecuted and very few and far between. If the difference was say, 40,000 sparrowhawks between then and now, and they each ate 1 sparrow a day, that would be 14 million less sparrows a year. Plus, every day I see loads of magpies (probably 10 or 20), which I believe eat other birds eggs. When I was a kid I don't think I ever saw one. I would guess the number of magpies must have risen 10 fold in the last 30-40 years. That must account for a fair few sparrows (and similar) as well. Certainly there are lots of aphids and the like in my garden in the summer and I would have said that most gardeners nowadays used less chemicals than 30 years ago. You certainly cant have a rise in the number of predators and expect the prey to remain constant, You can, if the predation is not the main thing controlling the prey numbers. If the limiting factor is breeding sites and food sources in winter, the ones eaten will just leave more resources for the others and the population level stays precisely the same. after all isn't that the point of all this organic gardening we hear about, encouraging predators such as hoverfly and ladybirds into gardens? If that works for them, I don't see why it wouldn't work for sparrow hawks/ sparrows as well. How do you do that encouragement? Are you bringing/attracting these creatures in from elsewhere? I believe one trick would be to attract more insects in general so that there is a wide selection of prey for them. It would certainly work on a local level if you set up your garden to be an ideal killing zone for the sparrowhawk - but that would probably not effect the overall populations averaged out over the sparrowhawk's range. An equivalent might be to feed a predator and keep its level at higher levels (ie domestic cats, corvids given sources of carrion that help them get through winter in greater numbers) This is nothing like the case with the sparrowhawks (although perhaps all those well fed tits could make a minor difference through the winter). "I don't see" Glad to see such an admission of cluenessness OK, so if you're so clued up, give us the benefit of your all-knowing wisdom, or do you just do poor sarcasm? With that level of radio2 lunchtime ramblings I'd have thought it wasn't worth it. Its about reaching levels of year-round semi-equilibrium, and what the limiting factors are. Sparrowhawks are unlikely to overexploit their area and cause population crashes. (and you know, they eat lots of birds that are having no problems at all, or increasing). |
#199
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Lack of invertebrates / house sparrows (was Reed Buntings)
"Tumbleweed" wrote in message . .. "W K" wrote in message ... "Oz" wrote in message news Tumbleweed writes ISTR reading a few years ago that the number of sparrow hawks had risen hugely since the 1940's, maybe to 50,000 or more, whereas 60 years ago or so they were persecuted and very few and far between. If the difference was say, 40,000 sparrowhawks between then and now, and they each ate 1 sparrow a day, that would be 14 million less sparrows a year. Plus, every day I see loads of magpies (probably 10 or 20), which I believe eat other birds eggs. When I was a kid I don't think I ever saw one. I would guess the number of magpies must have risen 10 fold in the last 30-40 years. That must account for a fair few sparrows (and similar) as well. Certainly there are lots of aphids and the like in my garden in the summer and I would have said that most gardeners nowadays used less chemicals than 30 years ago. You certainly cant have a rise in the number of predators and expect the prey to remain constant, You can, if the predation is not the main thing controlling the prey numbers. If the limiting factor is breeding sites and food sources in winter, the ones eaten will just leave more resources for the others and the population level stays precisely the same. after all isn't that the point of all this organic gardening we hear about, encouraging predators such as hoverfly and ladybirds into gardens? If that works for them, I don't see why it wouldn't work for sparrow hawks/ sparrows as well. How do you do that encouragement? Are you bringing/attracting these creatures in from elsewhere? I believe one trick would be to attract more insects in general so that there is a wide selection of prey for them. It would certainly work on a local level if you set up your garden to be an ideal killing zone for the sparrowhawk - but that would probably not effect the overall populations averaged out over the sparrowhawk's range. An equivalent might be to feed a predator and keep its level at higher levels (ie domestic cats, corvids given sources of carrion that help them get through winter in greater numbers) This is nothing like the case with the sparrowhawks (although perhaps all those well fed tits could make a minor difference through the winter). "I don't see" Glad to see such an admission of cluenessness OK, so if you're so clued up, give us the benefit of your all-knowing wisdom, or do you just do poor sarcasm? With that level of radio2 lunchtime ramblings I'd have thought it wasn't worth it. Its about reaching levels of year-round semi-equilibrium, and what the limiting factors are. Sparrowhawks are unlikely to overexploit their area and cause population crashes. (and you know, they eat lots of birds that are having no problems at all, or increasing). |
#200
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Lack of invertebrates / house sparrows (was Reed Buntings)
"Tumbleweed" wrote in message . .. "W K" wrote in message ... "Oz" wrote in message news Tumbleweed writes ISTR reading a few years ago that the number of sparrow hawks had risen hugely since the 1940's, maybe to 50,000 or more, whereas 60 years ago or so they were persecuted and very few and far between. If the difference was say, 40,000 sparrowhawks between then and now, and they each ate 1 sparrow a day, that would be 14 million less sparrows a year. Plus, every day I see loads of magpies (probably 10 or 20), which I believe eat other birds eggs. When I was a kid I don't think I ever saw one. I would guess the number of magpies must have risen 10 fold in the last 30-40 years. That must account for a fair few sparrows (and similar) as well. Certainly there are lots of aphids and the like in my garden in the summer and I would have said that most gardeners nowadays used less chemicals than 30 years ago. You certainly cant have a rise in the number of predators and expect the prey to remain constant, You can, if the predation is not the main thing controlling the prey numbers. If the limiting factor is breeding sites and food sources in winter, the ones eaten will just leave more resources for the others and the population level stays precisely the same. after all isn't that the point of all this organic gardening we hear about, encouraging predators such as hoverfly and ladybirds into gardens? If that works for them, I don't see why it wouldn't work for sparrow hawks/ sparrows as well. How do you do that encouragement? Are you bringing/attracting these creatures in from elsewhere? I believe one trick would be to attract more insects in general so that there is a wide selection of prey for them. It would certainly work on a local level if you set up your garden to be an ideal killing zone for the sparrowhawk - but that would probably not effect the overall populations averaged out over the sparrowhawk's range. An equivalent might be to feed a predator and keep its level at higher levels (ie domestic cats, corvids given sources of carrion that help them get through winter in greater numbers) This is nothing like the case with the sparrowhawks (although perhaps all those well fed tits could make a minor difference through the winter). "I don't see" Glad to see such an admission of cluenessness OK, so if you're so clued up, give us the benefit of your all-knowing wisdom, or do you just do poor sarcasm? With that level of radio2 lunchtime ramblings I'd have thought it wasn't worth it. Its about reaching levels of year-round semi-equilibrium, and what the limiting factors are. Sparrowhawks are unlikely to overexploit their area and cause population crashes. (and you know, they eat lots of birds that are having no problems at all, or increasing). |
#201
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Lack of invertebrates / house sparrows (was Reed Buntings)
In message , shazzbat
writes SNIP Birds nesting in my eaves observed using an oscilloscope. They're clever little buggers aren't they? I saw the blackbirds in our garden recently assembling an electron microscope. I reckon the magpies thieved it for them. That's nothing - the birds in my back garden are building an A-bomb! ;-) -- Five Cats Email to: cats_spam at uk2 dot net |
#202
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Lack of invertebrates / house sparrows (was Reed Buntings)
In message , shazzbat
writes SNIP Birds nesting in my eaves observed using an oscilloscope. They're clever little buggers aren't they? I saw the blackbirds in our garden recently assembling an electron microscope. I reckon the magpies thieved it for them. That's nothing - the birds in my back garden are building an A-bomb! ;-) -- Five Cats Email to: cats_spam at uk2 dot net |
#203
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Lack of invertebrates / house sparrows (was Reed Buntings)
On Tue, 23 Mar 2004 18:51:06 +0000, Five Cats ]
wrote: That's nothing - the birds in my back garden are building an A-bomb! ;-) and your cats WMDs in the Anderson shelter? |
#204
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Lack of invertebrates / house sparrows (was Reed Buntings)
In message , shazzbat
writes SNIP Birds nesting in my eaves observed using an oscilloscope. They're clever little buggers aren't they? I saw the blackbirds in our garden recently assembling an electron microscope. I reckon the magpies thieved it for them. That's nothing - the birds in my back garden are building an A-bomb! ;-) -- Five Cats Email to: cats_spam at uk2 dot net |
#205
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Lack of invertebrates / house sparrows (was Reed Buntings)
On Tue, 23 Mar 2004 18:51:06 +0000, Five Cats ]
wrote: That's nothing - the birds in my back garden are building an A-bomb! ;-) and your cats WMDs in the Anderson shelter? |
#206
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Lack of invertebrates / house sparrows (was Reed Buntings)
"Five Cats" ] wrote in message ]... In message , shazzbat writes SNIP Birds nesting in my eaves observed using an oscilloscope. They're clever little buggers aren't they? I saw the blackbirds in our garden recently assembling an electron microscope. I reckon the magpies thieved it for them. That's nothing - the birds in my back garden are building an A-bomb! ;-) That'll show your 5 cats who's boss :-)) |
#207
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Lack of invertebrates / house sparrows (was Reed Buntings)
In message , shazzbat
writes SNIP Birds nesting in my eaves observed using an oscilloscope. They're clever little buggers aren't they? I saw the blackbirds in our garden recently assembling an electron microscope. I reckon the magpies thieved it for them. That's nothing - the birds in my back garden are building an A-bomb! ;-) -- Five Cats Email to: cats_spam at uk2 dot net |
#208
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Lack of invertebrates / house sparrows (was Reed Buntings)
"Five Cats" ] wrote in message ]... In message , shazzbat writes SNIP Birds nesting in my eaves observed using an oscilloscope. They're clever little buggers aren't they? I saw the blackbirds in our garden recently assembling an electron microscope. I reckon the magpies thieved it for them. That's nothing - the birds in my back garden are building an A-bomb! ;-) That'll show your 5 cats who's boss :-)) |
#209
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Lack of invertebrates / house sparrows (was Reed Buntings)
On Tue, 23 Mar 2004 18:51:06 +0000, Five Cats ]
wrote: That's nothing - the birds in my back garden are building an A-bomb! ;-) and your cats WMDs in the Anderson shelter? |
#210
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Lack of invertebrates / house sparrows (was Reed Buntings)
On Tue, 23 Mar 2004 18:51:06 +0000, Five Cats ]
wrote: That's nothing - the birds in my back garden are building an A-bomb! ;-) and your cats WMDs in the Anderson shelter? |
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