The book by Gisela Kaplan about magpies has lots to say about their vocal
abilities and behaviour. They sing for similar reasons that most passerine
birds sing. Yet according to Prof Kaplan their vocal prowess is very well
developed with considerable learning abilities involved and capacity for
variation. Not only that but they sing with a wider variety of contexts than is
typical for most passerine birds. Both sexes sing throughout the year. As she
said on TV recently, they exhibit the vocal start of what we have usually
called cognitive development and leisure activity - this is a pretty unusual
bird - she says. She gave a lecture about this, in Canberra (at ANU) on
Saturday which was most interesting and attended by a big audience (including
me).
If the question is about it being "warbling" as a description of the type of
sound, well that is just the way it is and it really doesn't matter what it
sounds like to us. As for Graham's question, I can only suggest either there
is too much other noise or he is probably not listening properly (or he is not
a youngster any more and not near these birds in the mornings). Or they aren't
living in the parts of Sydney he is in. I doubt very much that there is any
part of their range where they don't call.
Philip
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