Display dispersion and diet of birds of paradise: a comparison of nine species

Summary

Birds of paradise (Paradisaeidae) are a diverse, poorly known group of tropical forest passerines. The majority of species (34 of 43) are sexually dimorphic, known or presumed to be promiscuous, and known to exhibit a range of male spacing patterns, from territoriality to lek behavior. In this study we mapped male dispersion in nine species of birds of paradise at three sites in Papua New Guinea. We observed four patterns: 1) Dispersed (territorial): Black-billed Sicklebill (Epimachus albertisi), Brown Sicklebill (E. meyeri), and Superb Bird of Paradise (Lophorina superba); 2) Dispersed (non-territorial): Magnificent Riflebird (Ptiloris magnificus), Magnificent Bird of Paradise (Diphyllodes magnificus), and Twelve-wired Bird of Paradise (Seleucidis melanoleuca); 3) Exploded lek: King Bird of Paradise (Cicinnurus reguis)-most males paired, and Lawes' Six-wired Bird of Paradise (Parotia lawesii); and 4) True lek: Raggiana Bird of Paradise (Paradisaea raggiana). These findings revise earlier assessments of spacing in some species, and the example of C. regius is the first documentation of a paired-male distribution for birds of paradise. In Table 3 we categorize all species of promiscuous birds of paradise into these four classes of dispersion. Comparison of diet with dispersion revealed a significant relationship between the extent of frugivory and the breakdown of widely-spaced territorial behavior. Obligate insectivores defended exclusive territories, while highly frugivorous species formed leks. Species with intermediate diets showed patterns of dispersion intermediate between these two extremes. Resource defense appears to be a viable option for species whose diet contains less than approximately 50% fruit.