Figure 4: Recognizability of host egg patterns is related to visual density and spatial dispersion.

(a) The most recognizable signatures (brambling, red-backed shrike and garden warbler) tend to have intermediate levels of visual density. Egg signatures with the highest visual density (reed warbler, pied wagtail and great reed warbler) are less recognizable. Quadratic model, P<0.001. (b) Signature recognizability is positively correlated with the degree of spatial dispersion in egg patterns. Weighted linear regression, P=0.007. Spatial dispersion is high in egg patterns exhibiting a high degree of spacing between distinctive features, such as in the brambling. Spatial dispersion may be a more reliable indicator of signature information content than visual density (a).