We got a pretty neat present today from Bruce Cousens and Charlene Lee of the Georgia Basin Ecological Assessment and Restoration Society (GBEARS) with the installation of four nest boxes for Purple Martins by the shore! Thanks also to the Bowser Irly Bird for donating the materials to mount the boxes! Read on about the recovery of Purple Martins which were once down to <10 nesting pairs in BC.
Photo: Sandy McRuer RainbirdExcursions via Flickr
Background from the GBEARS WEBSITE: Purple Martins (Progne subis) are the largest swallow in North America. The western subspecies (Progne subis arboricola) is threatened in British Columbia. Historically, Purple Martins nested in woodpecker holes in old trees or snags in open woodland areas or near freshwater and likely made extensive use of fire-killed stands. Due to logging, fire prevention, snag removal, burned timber salvage and agricultural and urban development throughout their original breeding range around the Georgia Basin, this habitat has been destroyed. Increasing populations of non-native European Starlings and House Sparrows also provide strong competition for any remaining nest cavities. By the early 1980s the BC population of western Purple Martins was reduced to less than 10 breeding pairs.
Since then, the British Columbia population of Purple Martins has rebounded to over 200 pairs by 2002 and ~650 pairs by 2007. This is largely due to the volunteer-based nest box program begun in the Georgia Basin area in 1986, as well as a similar program begun a decade earlier in Puget Sound, Washington, in 1975.
The BC population increased dramatically between 2003 and 2006, due in part to good weather conditions throughout the breeding season, resulting in an ample food supply of flying insects for both adults and nestlings. As for other swallows, the nesting success of Purple Martins is highly sensitive to adverse weather-induced reduction in food supply availability. An article about the history of the recovery of Purple Martins in BC, up to and including 2004, was printed in BirdWatch Canada (winter 2005 No. 30, p.21-22), a publication of Bird Studies Canada and is available here in .PDF format.
This program has been successful in creating a colony located on the pilings at the Deep Bay Harbour. All the nest boxes at the harbour are now full and it is our hope that last years young will start building a new colony next door at the Field Station. We’ll be watching eagerly to see if the new boxes are found over the next couple weeks.
Some of the summer students got an impromptu lecture from Charlene on Purple Martin ecology as the assembly went up. Great learning experiences all round. We also found that their was another VIU connection, the boxes were built by RMOT Instructor Greg Klimes.
Charlene and Bruce pose with the newly installed boxes. Note the cool rig so that they can be lowered down every winter for inspection and maintenance, For more information about GBEARS and the great work they do, check their website or contact Bruce and Charlene at coordinates below.
Bruce Cousens, B.Sc., M.Sc., R.P.Bio., Senior Biologist,
BC Purple Martin Stewardship & Recovery Program Coordinator,
Georgia Basin Ecological Assessment and Restoration Society
#4 – 1150 N. Terminal Ave., Unit 117, Nanaimo, BC V9S 5L6
Phone/msg./fax: (250) 758-2922; E-mail: firstname.lastname@example.org