Egg Speckling Patterns Do Not Advertise Offspring Quality or Influence Male Provisioning in Great Tits
Figure 2
Great tit eggs were photographed in the wild using a UV-sensitive camera, producing images in the (A) human-visible spectrum and (B) ultraviolet spectrum.
Images were converted to correspond to a blue tit’s (Cyanistes caeruleus) double cones (C). Egg patterns were measured using a digital image analysis technique (D) based on the fast Fourier transform, in which information about egg speckling is captured at different spatial frequencies. The original image is broken down into seven new images, each containing information at a different spatial scale. Low spatial frequencies (E) capture information about the relative contribution of large markings and high spatial frequencies (F) capture information about the relative contribution of small markings (see Stoddard and Stevens 2010 for details). Egg photograph by M. C. Stoddard.