On Jan 25, 12:40*am, "jbm" wrote:
"Stephen Wolstenholme" wrote in message

...
| On Sat, 24 Jan 2009 14:49:34 -0800 (PST), Andrew Stucken| wrote:

|
| I heard a bird singing all night long through the worst of the cold
| spell earlier this month. A pigeon I think. Does he know something we
| don't?
|
| It's caused by light pollution. Some birds just don't know when it's
| night and time to shut up.
|
| Steve
|

You could be right. Over the last week or so the pesky little critters have
started up here at 4 o'clock in the morning, making the dog think it's time
to get up and ask to go out for a wee.

jbm
(A not so dark) Northampton

I think birds can detect dawn earlier than us, as they seem to start
when it's still apparently dark. That said, astronomical twilight
(which is the first stage when there's some light about) seems to
begin 2 hours before sunrise or end 2 hours after, so 4am at this time
of year seems a bit early.

Nick