Evolution of nest architecture in tyrant flycatchers and allies.

Innovations in nest design are thought to be one potential factor in the evolutionary success of passerine birds (order: Passeriformes), which colonized new ecological niches as they diversified in the Oligocene and Miocene. In particular, tyrant flycatchers and their allies (parvorder: Tyrannida) are an extremely diverse group of New World suboscine passerines occupying a wide range of habitats and exhibiting substantial extant variation in nest design. To explore the evolution of nest architecture in this clade, we first described nest traits across the Tyrannida phylogeny and estimated ancestral nest conditions.

Convergent evolution of elaborate nests as structural defences in birds.

The pendent nests of some weaverbird and icterid species are among the most complex structures built by any animal, but why they have evolved remains to be explained. The precarious attachments and extended entrance tunnels characteristic of these nests are widely speculated to act as structural defences against invasion by nest predators, particularly tree-climbing snakes, but this hypothesis has yet to be systematically tested. We use phylogenetic comparative methods to investigate the relationship between nest structure and developmental period length, a proxy for offspring mortality, in weaverbirds (Ploceidae) and icterids (Icteridae), two bird families in which highly elaborate pendent nests have independently evolved.

Phylogenetic relationships of weaverbirds (Aves: Ploceidae): A first robust phylogeny based on mitochondrial and nuclear markers.

Weaverbirds are a diverse passerine group with species diversity concentrated in sub-Saharan Africa. No comprehensive phylogenetic hypothesis regarding relationships of weaverbirds has been produced, however, so we developed a first extensive phylogeny for the family Ploceidae, based on a multilocus dataset of three mitochondrial loci and four nuclear markers. Analysis of these data offered strong support for monophyly of the family and revealed seven distinct clades within Ploceidae.