"Nick Maclaren" wrote in message
...


| The increase in collared dove population is an interesting point,
because
| they are relative newcomers, and there does seem to be a correlation
between
| their establishment here and the sparrow decline, although that may
merely
| be coincidence. What is the 'realistic causal chain' you have in mind,
| though?

Winter and early spring feed. With the major reduction in fields left in
stubble over winter, the number of horses etc., seeds are in limited
supply.
Pigeons are much larger than sparrows, and bully them out of the way (as
well as eating much of what is available). It's one of the many plausible
speculations.

Not in my garden they don't. They co-habit very happily.

I think that there are local variations in the reports of sparrow numbers.
We have as many as ever, if not more. I used to count them for BTO but it
became impossible. There are no more collar doves than before, just one
breeding pair and their offspring until it's independent (perhaps they're
territorial)

Mary