"Oz" wrote in message
...
Thur writes

sparrowhawks (another post)
Predators may lower the population if they recover themselves from
population losses such as the agro-chemicals combined with
gamekeeper slaughter.

Apart from raptors, and then many years ago, I haven't heard of
gamekeepers shooting birds other than some corvids.

Shooting crows/pigeons was once the only shooting allowed to
farmworkers, which kept populations down 30 years ago.

Apart from DDT, banned in the early 1970's, do you have any evidence of
significant bird losses due pesticides?

Once established though, there should be a "natural" balance between
prey and predator numbers?

Yes, but this need not be, and often is not, a stable population as in
the same every year.

--
Oz
This post is worth absolutely nothing and is probably fallacious.
DEMON address no longer in use.

I do hear that the Goshawk is now returning to some areas,
and I see with my own eyes Buzzards wheeling overhead
(and searching our nesting sites) which were once completely
absent from my area. (North Midlands)
I hear (tv) that these predators were reduced by one or both of
the problems mentioned.
Poisoning and egg stealing and capture still go on if we are
to believe the Courts, where the odd one or two of those found
are fined.
Your trust in gamekeepers is heartening, but to a cynic like me,
mistaken. Their job is to increase their crop of game by suppressing
natural predation which increases with the increased prey supply.
How else can they keep their jobs?
But the point is that as predator numbers have risen, populations
of their prey will have reduced to a balance. Whether this accounts
for the sudden drop in sparrows mentioned is another matter.
I should have quoted that part of the other post to which I had been
referring.
T.