"Colonel Bloomer" wrote in message
...
On Mon, 22 Mar 2004 19:55:03 -0000, "Tumbleweed"
wrote:


"Colonel Bloomer" wrote in message
.. .
On Mon, 22 Mar 2004 17:20:45 +0000 (UTC), "W K"
wrote:


"Colonel Bloomer" wrote in message
.. .
On Mon, 22 Mar 2004 11:59:32 +0000 (UTC), "W K"

wrote:


"Colonel Bloomer" wrote in message
.. .
snips
I feel this is a bit more than the natural yoyo cycle of populations.

The cycle of populations.
When the sparrow population reached it's height, maybe there
was some vulnerability due directly to the closeness the birds
found themselves in.
Maybe some populations are in a "stable state" when they are
fluctuating?
sparrowhawks (another post)
Predators may lower the population if they recover themselves from
population losses such as the agro-chemicals combined with
gamekeeper slaughter.
Once established though, there should be a "natural" balance between
prey and predator numbers?
Another consideration may be that garden feeders may have increased,
and this is thought to unnaturally bring birds together more closely than
they would do elsewhere. I heard someone say that many deaths from
disease actually reduce numbers eventually around a feeder.
I have not noticed this myself, rather the opposite after more than 7 years.
T.