Welcome to the website of Darren Irwin’s research group. Our research is directed toward understanding how new species arise, how geographical variation within species is produced, and how behaviors evolve. We study carefully chosen model systems using an integrative approach, employing techniques such as DNA sequencing, computer-assisted analysis of vocalizations, observation and experimentation in the field, and computer simulation. Research systems have included passerine birds in Asia, Europe, and North America.
A few of our study organisms:
Greenish warblers in Asia show how geographic variation within a species can be used to reconstruct how new species arise. Click here to learn more about this ring species. Collaborators include Trevor Price, Staffan Bensch, Jessica Irwin, and Miguel Alcaide.
A hybrid zone between Audubon’s warblers (left) and myrtle warblers (right) was discovered in the 1960’s, causing the two to be lumped into a single species as yellow-rumped warblers. Ph.D. student Alan Brelsford (defended July 2010) studied molecular, phenotypic, and behavioral variation across the hybrid zone. He found that the hybrid zone is stable, and that there is some form of selection against hybrids maintaining the zone. For the publication, click here. Alan also led a study of genetic variation throughout the entire yellow-rumped warbler complex, showing that the Audubon’s warbler most likely originated through hybrid speciation. Click here for the paper, and here for the associated News and Views. Ph.D. student David Toews (defended April 2014) dramatically expanded the scope of our lab’s work on yellow-rumped warblers, examining the association between migratory behaviour and genetic divergence in both the southwestern USA and the Canadian Rockies. Undergraduate researcher Julian Heavyside is now collaborating with Dave and Wild Research on a study of isotopic variation in yellow-rumped warblers migrating through Vancouver.
In northeastern British Columbia, near the town of Tumbler Ridge, we have found a contact zone between distinct western and eastern forms of winter wrens. These forms differ dramatically in songs and genetics, and the two forms are reproductively isolated. Dave Toews (who did his M.Sc. on this system) and I proposed that the western form be elevated to species status as the “Pacific wren.” In 2010 the American Ornithologists’ Union officially recognized two distinct species in North America: the Pacific wren (Troglodytes pacificus) and the winter wren (Troglodytes hiemalis), both now distinct from the Eurasian wren (Troglodytes troglodytes). Click here to learn more, and to listen to their songs.
In the same region of northeastern British Columbia, we have recently discovered a hybrid zone between MacGillivray’s and mourning warblers. At right is a hybrid (a “MacMourning warbler”) identified using molecular markers. PDF Link
We have also discovered a hybrid zone between Townsend’s and black-throated green warblers in the same region. Click here for the paper describing this zone.