Birds-of-paradise exhibit extreme diversity in colors, sounds, and behaviors used during courtship displays, necessitating novel methods to quantitatively evaluate the evolution of their complexity.

(A) Sixteen exemplar species (purple tips) are shown with their phylogenetic relationships to highlight variation in plumage color, acoustic signals, and courtship display behavior. (B) Behavioral subunits were scored from field-captured videos of displaying males (S3 and S4 Tables). Behavioral subunits were combined to create composite behaviors describing any behavior across species and facilitating sliding-window analysis of behaviors and behavioral sequences. (C) UV and visual spectrum images were taken of museum specimens (S7 Table) and used to generate avian visual model-informed image stacks. Color values were clustered with respect to modeled avian discriminability, enabling whole-specimen quantification of color richness and diversity. (D) All bird-of-paradise sounds were placed into a multidimensional acoustic space defined by principal components analysis. Sounds were then given identities based on locations within acoustic space, facilitating a sliding-window analysis of sounds and acoustic sequences (S8 and S9 Tables). lws, long-wavelength sensitive; mws, medium-wavelength sensitive; sws, short-wavelength sensitive; UV, ultraviolet; uvs, ultraviolet sensitive.