nightjar wrote in message
. ..

"BAC" wrote in message
...

nightjar wrote in message
.. .

"Jane Ransom" wrote in message
...
In article ,
nightjar@?.?
writes

'Despite the large numbers of birds killed, there is no scientific
evidence
that predation by cats in gardens is having any impact on bird
populations
UK wide.

Not my words, but those of the RSPB.


Must be right, then ...

It is not inconsistent with the claim that areas with cats have fewer
birds.
The RSPB also points out that there is evidence that cats tend to take
birds
that are sickly or weak and concludes that the majority of those caught by
cats would probably not have survived to breed the next season. It is the
number of breeding birds that determines the threat, or lack of threat to
the bird population. If an area with cats does have fewer birds, then if
the
population also comprises a higher proportion of breeding birds, but fewer
weak or sickly birds, both statements can be correct.


I don't doubt it. Culling/predation seems more likely to affect the average
age and fitness of a population, rather than the numbers of the pre-breeding
'prey' population, providing there is some sort of balance.

However, the population density of domestic cats has nothing to do with the
carrying capacity of their territories, so, in areas where cats are thick on
the ground, there seems likely to be a disproportionately high level of
predation.

I would be surprised if cat predation were not 'a' factor in the observed
decline of certain species in some locations.