In article ,
Malcolm wrote:
In article , ned writes

I think it is. Here are some counts of the numbers in Kensington
Gardens, London, made by Max Nicholson:

November 1925 - 2,603
December 1948 - 885
November 1966 - 642
November 1975 - 544
February 1995 - 46

This decline, in central London, which has been going on for more than
50 years, is attributed, firstly, to the disappearance of horses from
the streets and, secondly, as already mentioned, to the absence of
nesting places in modern buildings.

Well, I will swallow the first as a very likely cause of the decline
from 1925 to 1948. The latter is pretty dubious, because there are
still a lot of older buildings around, sparrows aren't all that fussy
and smaller numbers need fewer places. c.1985, we had some nesting
behind the guttering in a (then) new extension. It is almost certainly
a cause for some birds, but sparrows?

The decline in farmland also dates to earlier than 1970, with the
widespread introduction of tractors in place of horses and all that
meant over the next decades in terms of cleaner arable fields, loss of
hedgerows, more rapid ploughing, etc., etc.

And there has been very little change since 1975 over most of the
south-east, certainly not enough to account for a tenfold reduction
(unless you bring in the passenger pigeon effect, which is not
intrinsically impossible, but is a bit implausible).

My hypothesis is that many declines have been due to cats - and I
don't mean feral ones. If you consider the proportion of the south
east that (a) has vegetation and (b) is outside the territory of
any cats, it HAS decreased by tenfold or more since 1966. Whether
this is the cause for sparrows, I can't say.

What we need is some larger predators, both to keep the deer down
(especially for birds that rely on woodland undergrowth) and to keep
the cats down. Bring back lynx. I know that you disagree, but I
can't understand why - it is not as if any likely prey of lynx are
even rare, with the POSSIBLE exception of a few birds that are
currently seriously endangered by the combination of deer and cats.


Regards,
Nick Maclaren.