The origin, distribution, and function of biological diversity are fundamental themes of
ecology and evolutionary biology. Research on birds has played a major role in the history …

Birds exhibit remarkable variation in plumage patterns, both within individual feathers and
among plumage patches. Differences in the size, shape, and location of pigments and …

Species delimitation requires a broad assessment of population-level variation using
multiple lines of evidence, a process known as integrative taxonomy. More specifically …

Hybridization—the interbreeding of different species—plays an integral role in the evolution
of numerous bird species. However, it remains unclear how widespread this phenomenon is …

Closely related species with parapatric elevational ranges are ubiquitous in tropical
mountains worldwide. The gradient speciation hypothesis proposes that these series are the …

As a dispersive lineage expands its distribution across a heterogeneous landscape, it
leaves behind allopatric populations with varying degrees of geographic isolation that often …

Natural hybrid zones provide powerful opportunities for identifying the mechanisms that
facilitate and inhibit speciation. Documenting the extent of genomic admixture allows us to …

The “paradox of the great speciators” has puzzled evolutionary biologists for over half a
century. A great speciator requires excellent dispersal propensity to explain its occurrence …

Allopatric speciation followed by the evolution of range overlap (sympatry) allows the build‐
up of regional diversity. However, local species richness requires that species co‐occur …

When a single species evolves into multiple descendent species, some parts of the genome
can play a key role in the evolution of reproductive isolation while other parts flow between …