A Natural Experiment on the Condition-Dependence of Achromatic Plumage Reflectance in Black-Capped Chickadees
2011

Black-Capped Chickadees' Plumage Reflectance and Disease State

Sample size: 20 publication Evidence: high

Author Information

Author(s): D'Alba Liliana, Van Hemert Caroline, Handel Colleen M., Shawkey Matthew D.

Primary Institution: University of Akron

Hypothesis

Birds afflicted with avian keratin disorder would show reduced expression of black and white, but not grey, color.

Conclusion

The study found that black and white plumage color in black-capped chickadees reflects their disease state, with affected birds showing reduced color expression due to feather soiling.

Supporting Evidence

  • Feathers of affected birds had a matted appearance with large deposits of debris.
  • UV-vis spectrometry revealed spectral differences between affected and unaffected birds.
  • Experimentally cleaning the feathers increased color expression of ornamental feathers in affected birds.

Takeaway

Sick black-capped chickadees have dirty feathers that make them look less colorful, which can show other birds that they are not healthy.

Methodology

The study used UV-vis spectrometry, scanning electron microscopy, and a feather cleaning experiment to analyze plumage reflectance.

Limitations

The study's sample size was limited, which may affect the generalizability of the findings.

Participant Demographics

The study involved 10 affected and 10 unaffected black-capped chickadees from Alaska.

Statistical Information

P-Value

p<0.05

Statistical Significance

p<0.05

Digital Object Identifier (DOI)

10.1371/journal.pone.0025877

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