A postscript to my message posted last night, Thursday, 13 March 2003 10:24
PM.
Dean had questioned my proposition that with Superb Lyrebirds "if anyone
took the trouble to tape-record and analyse the mimicry from all the
individuals in one area, it would be found that they all use the same suite
of mimicked sounds".
In commenting on that, I had intended to add that in the summary at the
beginning of the paper that Dean quoted (Robinson and Curtis (1996; Emu 96:
258-275)), was this statement:
"Lyrebird vocal display consists of mimicry of natural sounds
interspersed with territorial song and other specific signals. Mimicked
sounds are culturally transmitted by adult males and not learned by young
birds from the models, but further sounds may be subsequently added to or
delete from the repertoire."
Dean was right in believing that most of my experience has been with
Albert's Lyrebirds. In the paper cited, Norman wrote the Superb part and the
overall conclusions; I contributed the Albert's part. With respect to the
above statement, I knew it to be correct for Albert's and had no reason to
question Norman's belief that it applied to Superbs. He had, after all,
carried out a major CSIRO research project on the Tidbinbilla Superbs under
the supervision of Harry Frith, Chief of the Division of Wildlife Research,
and himself a very knowledgeable person where lyrebirds were concerned.
This lasted from 1959 to the mid-1960s.
And to get back to Tony Russell's original query, I must add that Dean is
right in saying "that mimicry away from the display mound constitutes more
than a minor amount of the total mimicry given."
I believe I am right in saying that with Albert's almost all breeding season
mimicry is given from the display platforms, but I was wrong in saying this
applied to the Superb. I should have re-read the Robinson/Curtis paper!
Re-read it? I should have read it more carefully before it was published!
This is what Norman wrote (and I accepted!):
"Observations in Sherbrooke Forest, where Superb Lyrebirds are less
timid, showed that males produced short bouts of singing while feeding after
the intense early morning displays. This behaviour is also implied in the
performance of bird D at Tidbinbilla, by shorter bouts between 0909 and 1053
h, the absence of clicks, and the lower incidence of pliks during this
period. The time spent by bird D in vocal display at the mounds (Table 2)
was investigated by placing microphones to track the bird around his
territory, supplemented by additional microphones on active mounds (Robinson
& Frith 1981), Although more mounds were used at the height of the breeding
season the proportion of time in display at the mounds increased steadily
throughout."
Norman's Table shows the percentage of display at mounds rising from 22% on
June 10, to 51% by 14 July, and up to 74% on both August 20 and September 3.
I find it surprising that through June and up to mid-July more time is spent
in singing away from the mounds that at them. (And I assume much of the
singing is mimicry.)
Alas, both Norman and Harry are no longer with us, so I cannot ask them to
comment.
Syd
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