canberrabirds
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To: | <> |
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Subject: | cisticolas and others breeding |
From: | "Philip Veerman" <> |
Date: | Fri, 24 Jan 2014 22:12:49 +1100 |
Martin's examples are fine and there are any number of other
examples. Martin's concept seems as good as any other suggestion to me, although
probably requires a time context (as in immediate). It is not always behaviour
by the male. For example I think the female sexual solicitation behaviour by the
Pied Currawong is far more obvious than the male's courting behaviour. In that
case I guess a Co is one up in usefulness scale than a Di. So by all means
include Di data if you are sure that is what it is and you wish, because that is
what our data forms allow but I wouldn't worry about it too much. I suspect some
things are recorded as displays that may be behaviour unconnected with "behaviour intended to persuade a
bird of the opposite sex to copulate". Because maybe the observer does
not know what it is. I think it pretty pointless to label every Cisticola
singing at the top of a grass stem as a breeding record (I not sure that was
being suggested). Then many other species do routines that are nowhere near as
obvious (at least to us).
I last
commented on this question, in relation to the issue of cuckoos having a brood
patch, as to what we should include as breeding records. My opinion is that
including "display" as a breeding record is a fairly vacuous bit of data, unless
it is followed up by later data demonstrating the breeding. This normally
applies more to GBS methods because that is more likely to follow the activities
of a particular set of birds at a site, than other types of COG surveys when
often you never see those birds again. Thus the one GBS breeding record of a
Wedge-tailed Eagles perform a
spectacular display flight is hardly worth
the bother, as it clearly was not breeding in the site, all it does is set a
date. I wrote a couple months ago of having a Hobby flying around the tree
in my yard and investigating the abandoned Pied Currawong nest. If it had stayed
and started nesting then I would record that as a Di to set a date. But it
didn't so I have not recorded the behaviour as it simply isn't useful and
because without proof of later evidence I cannot be sure I was interpreting the
behaviour correctly. Likewise all the Crested Pigeon bowing
displays are only notable to set dates and should be considered only as part of
better evidence of breeding. All the Satin Bowerbirds bower activities are entertaining but don't tell us much about
breeding as they are probably not breeding locally anyway. It just tells us
that the males are highly
motivated.
Years
ago I wrote an article in CBN of observing White-throated Needletails doing what
looked like engaged in pair chasing display (over Tuggeranong Hill). Others have
also published similar. The species doesn't breed in Australia but maybe goes
through what presumably is "behaviour intended to persuade a bird of the opposite
sex to copulate".
Philip
-----Original Message----- From:
Martin Butterfield [
Sent: Friday, 24 January 2014 5:35 PM To: John Harris Cc: Bill & Raelene; Subject: Re: [canberrabirds] cisticolas breeding I don't count myself as 'learned' but here is an opinion.
I have never seen a 'universal' definition of what is a breeding display
written down. The concept is something along the lines of "behaviour
intended to persuade a bird of the opposite sex to copulate".
This covers a large range of species-specific behaviours:
I'm not sure that it is always the male that is the actor, but whether the
other participant is visible depends on the situation. I've certainly seen
male Satin Bowerbirds going though a very vigorous display routine without a
female in sight for several minutes. Then she has emerged from dense
undergrowth at which point I offered them privacy. Clearly what the male
was doing was DIsplay and would have been even if I had left before the female
revealed herself to me (I suspect the BB knew she was there all along).
Martin On 24 January 2014 16:47, John Harris <> wrote:
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