Hi –
It would be quite straightforward to determine whether there are differences or significant differences in the vocalisations – calls and songs of the various Shrike-tits, …..if a group of birding-aus-ers were to collaborate. The difficulty might be getting enough sound recording samples.
Could try state govt workers/birders naturalists for more recordings.
For each taxa you might try to get at least 5 songs [larger sample would be better of course], and at least 5 contact notes, determine song characteristics of the vocalisations [means etc using “Excel”]- max. frequency, min frequency, song length, pace (time between songs if relevant) – portray these on sonagrams and see if they look different, and where sample sizes allow, try some simple statistics [available on the internet or Excel].
If one of the taxa has a particular song or call type that is totally unlike other taxa, that would be of value to document. The basic documentation and description of calls and songs of each taxa would be of value on its own.
You might call it a “Preliminary examination of species limits in Shrike-tits…” and it would be publishable in Aust Field Ornithologist, or elsewhere [one of the collaborators would need to be keen to write].
Creating sonograms and calculating song characteristics could be done in Raven Lite program, free download:
http://www.birds.cornell.edu/brp/RavenLite/RavenLiteDownload.html
Theres many examples of such analyses, heres one showing sonograms of various geographic representatives of the “Large-billed Crow” of Asia:
http://www.xeno-canto.org/feature-view.php?blognr=109.
Colin
To:
Subject:
Shrike-tit calls
From:
Graeme Chapman
Date:
Sun, 13 Jan 2013 16:14:17 +1100
Hello Peter,
Just to pick up on your comment that “I’m not sure where Phil’s idea of ‘very different Calls’ comes from”. Until I’d spent some time at O’Reillys in the rainforest I would have agreed with Phil – the calls of Northern Shrike Tits do sound different to Eastern Shrike-tits but now that I have had more experience I would modify that statement to ……sound different to most Eastern Shrike-tits.
In my experience, the rainforest inhabiting birds at O’Reillys (a very odd habitat for a Shrike-tit) do have in their repertoire calls that are almost identical to the northern Shrike-tits at Drysdale River. I’ve heard and recorded lots of Eastern Shrike-tits and haven’t heard “northern” type calls anywhere but at O’Reillys. I would be interested to know where you’ve heard these calls in the east – they must surely occur elsewhere because you are obviously familiar with them. Unfortunately we know so little about the entire repertoire of all but a few of our native birds in Australia that it’s downright embarrassing.
For those who are interested in the different Shrike-tit calls, my website has a good selection where they can be compared easily .
Cheers
Graeme Chapman ===============================
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