Data from: Parallel evolution of bower-building behavior in two groups of bowerbirds suggested by phylogenomics

The bowerbirds in New Guinea and Australia include species that build the
largest and perhaps most elaborately decorated constructions outside of
humans. The males use these courtship bowers, along with their displays,
to attract females. In these species, the mating system is polygynous and
the females alone incubate and feed the nestlings. The bowerbirds also
include 10 species of the socially monogamous catbirds in which the male
participates in most aspects of raising the young. How the bower-building
behavior evolved has remained poorly understood, as no comprehensive
phylogeny exists for the family. It has been assumed that the monogamous
catbird clade is sister to all polygynous species. We here test this
hypothesis using a newly developed pipeline for obtaining homologous
alignments of thousands of exonic and intronic regions from genomic data
to build a phylogeny. Our well-supported species tree shows that the
polygynous, bower-building species are not monophyletic. The result
suggests either that bower-building behavior is an ancestral condition in
the family that was secondarily lost in the catbirds, or that it has
arisen in parallel in two lineages of bowerbirds. We favor the latter
hypothesis based on an ancestral character reconstruction showing that
polygyny but not bower-building is ancestral in bowerbirds, and on the
observation that Scenopoeetes dentirostris, the sister species to
one of the bower-building clades, does not build a proper bower but
constructs a court for male display. This species is also sexually
monomorphic in plumage despite having a polygynous mating system. We argue
that the relatively stable tropical and subtropical forest environment in
combination with low predator pressure and rich food access (mostly fruit)
facilitated the evolution of these unique life-history traits.