Thanh-Lan Gluckman
Cambridge International Scholarship funded PhD
Supervisor: Nick Mundy
- Tel: +44 (0) 1223 331 771
Fax: +44 (0) 1223 336 676
Current Research
Birds often possess spectacular within feather patterning, for example, the spotted tail feathers of the peacock or the wonderful barred plumage of cuckoos and raptors. Although they are ubiquitous, and often exquisite in their arrangement and coloration, only a few studies have sought to understand their functional and evolutionary significance.
Reaction-diffusion is the model which has been proposed to describe how within feather patterning, such as bars and spots, are formed during feather growth. In particular, I am interested in whether this model has implications for our understanding of the evolution of within feather patterning. The majority of work conducted on plumage patterns, with few exceptions, has centred on their function - specifically camouflage. However, my previous research shows that some patterns have also evolved under sexual selection, and may be used in communication. I am interested in how development and natural selection have shaped the patterns we see today, how they might have interacted, and what this can tell us about function and evolution.
My research proposal combines a number of inter-disciplinary research methods; I use computer modelling and image processing to explore how birds see patterns and pattern colour using specimens from museums, Bayesian based computer modelling to trace plumage pattern evolution, and lab based molecular techniques to understand how they are formed. The predominant model systems I work on are the bird groups with the most spectacular plumage patterns in the world - Anseriformes and Galliformes (i.e. ducks, peacocks, pheasants) - and the peculiar system of mimicry in Cuckoos and Raptors. Eventually, I hope to combine patterning from a birds perspective, with pattern formation from the molecular level, to understand how these two processes have interacted to bring about the wonderful array of bird plumage patterns that we see today.
Software
Barred plumage is common among bird species. It is often interpreted as a form of crypsis because pigmentation patterns are less detectable against heterogeneous backgrounds. However, it has also been suggested that barred plumage could signal plumage condition, because it makes irregularities in the plumage perceptually salient. Little empirical work exists on the function of barred plumage, in part because we lack a way for quantifying the regularity of the pattern. To address this gap, Dr. Gonçalo Cardoso and I developed software to analyse the regularity of barred plumage patterns.
Example of input (a) and output images (b and c) for the analysis of plumage regularity, using G. philippensis. a Photograph of barred plumage, b image converted to black and white, and c aligned image. Input and output images d and e illustrate the correction for curvature, or tilt, and perspective, on an artificial pattern. The vertical stripes on the right side of c and d indicate the color homogeneity of each row of pixels.
The software runtime environment and executable (PC) is freely available: MCRInstaller.exe and Barred.exe
The Matlab code for non PC based computers is available on request.
Publications
- Gluckman T-L and Cardoso GC (2010) The dual function of barred plumage in birds: camouflage and communication. J. Evol. Biol., 23, 11:2501-2506
(Covered by: The Age newspaper (October 12th 2010), Science Daily online (September 20th 2010), Australian Geographic online (September 21st 2010), ABC 774 live to air (September 21st 2010). - Gluckman T-L and Cardoso GC (2009) A method to quantify the regularity of barred plumage patterns. Behav. Ecol. Sociobiol. 63:1837-1844
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