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Every
afternoon, before, sunset, starlings gather in the
dead tops of these tall spruces. Small groups fly in
and settle and there is constant music and movement as
the birds sing and preen, and flit from perch to
perch. The singing creates a background of chattering
and whistling which is sometimes called a 'murmuration'
although, if the flock is large, it is hardly the
subdued sound that the name implies.
No one seems
to know why starlings sing at this time but one of the
peculiar features of a murmuration is that the chorus
builds up, then suddenly ceases as if a switch has
been thrown. How the sudden cut-off of song is co-ordinated
is quite unknown but it is usually followed by some or
all the starlings flying off. Some disappear, perhaps
joining another flock passing by and heading for the
overnight roost; others circle and land again. More
birds arrive, the murmuration builds up and there is
another dramatic silence followed by another
departure.
One theory is
that the murmuration cut-off helps to co-ordinate the
instantaneous departure of the flock, but this begs
the question as to how the cut-off is itself co-ordinated.
Furthermore, starlings often take-off together without
a murmuration. However, there is sense in a
simultaneous movement because flying in a dense flock
is a good defence against predators.
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