?On common ground after icy split? – the talk by Dr Darren Irwin, hosted by the Tumbler Ridge Museum Foundation (TRMF) and Tumbler Ridge Public Library on 29 May, proved to be a fascinating event. Dr Irwin is Assistant Professor of Zoology at UBC, and he studies speciation: how bird a species over time may become divided into different population that can no longer breed with each other.
It turns out that Tumbler Ridge is one of the finest places in North America to study this phenomenon, as eastern and western populations that became isolated from each other during repeated glacial periods, have now re-encountered each other here, partly because the Rocky Mountains are fairly low here. Through the work of Dr Irwin and his assistant David Toews, intriguing results are emerging, using tools like mitochondrial DNA analysis, and sophisticated analysis of bird song.
Dr Irwin has focussed on the Winter Wren in particular, as well as other east-west species pairs like the Mourning and MacGillivray?s Warblers. He was fortunate to find both the eastern and western forms of Winter Wren occurring close to each other on the Quality Falls Trail near Tumbler Ridge. The research suggests that it is possible that a new bird species will be described in North America, as the wren population will probably be split into two separate species, as even at this meeting point the eastern and western forms have distinctly different songs, and don?t appear to interbreed. The research has demonstrated that the two populations became separated as far back as 2.8 million years ago. Old growth forest is required habitat for these wrens, and Dr Irwin pointed out that the amount of clearcutting of this type of forest in this meeting zone is an obvious concern.
Over 30 people attended the illustrated talk, with time for questions. By the end of the evening the audience was able to easily distinguish between the eastern and western songs, and was encouraged to report their wren records to Dr Irwin, who hopes to continue his research in the Tumbler Ridge area for years to come.
His remarkable work, which emphasizes the importance of places like Tumbler Ridge in North American ornithology, will form the subject of a new TRMF exhibit in the Community Centre. This will be formally opened on June 27th. For more information visit www.zoology.ubc.ca/~irwin/ and click on ?wrens? for details on the Tumbler Ridge wren research.