Wednesday 4 March 2015

Colour - Chiffchaff Colour Profile Revisited

While researching colour in May 2014 I came up with a concept which I call Colour Profiling or CP.  The idea is to use digital colour management and colour sampling techniques to try and create colour profiles to aid in separating very similar species/taxa based on digital images.  I thought Chaffchaffs would be a good place to start and I came up with a CP template for Chiffchaff which I have been trying to test ever since.  

While I am still working on this concept it has taken me considerable time to finally catch up with a tristis-type Chiffchaff.  After a rather poor autumn for putative tristis, this winter has been remarkable here in Ireland, yet I havn't been fortunate enough to catch up with any until now.  It is quite late in the winter so plumage wear is a factor but, in any case I managed to get a nice shot of a tristis candidate at Rossmore Quarry, Co. Cork today.  This was one of three birds present, none of which were calling today (so I can't be certain of the identification of this individual).  Nonetheless this was a useful exercise as I was able to compare a collybita photographed under the same conditions.  I played a brief segment of tristis calls and was immediately buzzed at close range by the three putative tristis while a nearby collybita remained rather disinterested (for what that is worth).

Possible Siberian Chiffchaff Phylloscopus collybita tristis, Rossmore Quarry, Co. Cork.

Typical Common Chiffchaff Phylloscopus collybita collybita, Rossmore Quarry, Co. Cork.

Prior to creating a colour profile from the images above I first calibrated their colours using the X-rite Colorchecker Passport.  For more on this process see HERE.  

The CPs below were created by sampling colours from the above images.  The CP is a colour map made up of carefully selected colours samples.  I am not entirely happy with the way the CP is set up at the moment so it will need a bit of rework but hopefully the value of it is apparent from this illustration.  The colour nomenclature which I have used here is based on the Birder's Colour Pallet which I created for the blog last year.

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