Today, the marina is quiet. Absent is the communal chatter of Purple Martins socializing atop their favourite wind indicator or chasing off crows and seagulls who venture too close to their nest boxes. Most of the Purple Martins have left for their long migration south and their departure signals the end of summer.
Natural habitat for Purple Martins is in the cavities of old trees especially along coastal areas, near or on open water. However, in 1985 the future of the Purple Martins in southwestern British Columbia was bleak with only 5 known nesting pairs. Loss of habitat was a major contributor to the decline in the Martin population.
Volunteers from the BC Purple Martin Stewardship and Recovery Program created a nest box program to replace the lost habitat. Luckily, the Martins liked their new accommodations and their numbers started to increase. There are approximately 1200 nest boxes in over 60 marine sites along Georgia Strait and the Lower Mainland and in 2007, the program recorded over 600 nesting pairs. The program has been so successful that most of the local Martins have only nested in man-made nest boxes.
Migrating Purple Martins nest from southern California to Campbell River and Powell River at the northern limits of their range. On Vancouver Island, adult Purple Martins (2 years+) usually return to their nesting colonies in April, establish nests and fledge the young just in time to make the long journey back to South America by mid to late August. Sub-adult birds (last year’s fledglings) migrate later and continue arriving until at least the end of June, so that nesting becomes staggered across the colony.
The Martins disperse widely looking for vacant nest sites in established colonies, keeping the gene pool well mixed, and will often colonize new nesting sites. Through the monitoring of banded Martins, researchers have observed that most Martins do not return to their natal colonies.
A continued threat to Purple Martins comes from two competing, non-native bird species which were introduced to the detriment of native birds. Starlings and House Sparrows live year-round in this area, so are able to squat in Martin nests, so that when the Martins arrive from South America, there are no available nesting sites. To help mitigate this problem, nest box openings are constructed to strict measurements to prohibit Starlings from overtaking Martin nests, but the smaller House Sparrows can fit inside. Ideally, Martin nest boxes should be removed or the entrance blocked once the birds have left for South America in the fall to eliminate this problem.
Purple Martins enjoy a diet of insects, insects and more insects. They usually forage high-flying insects but do enjoy dragon flies. Last summer, a Martin followed a dragon fly into our cockpit, snatched it up in his beak and returned to his waiting offspring.
So what can you do to help support the efforts of the Recovery Program? Donations are always welcome or you can adopt a Martin. Volunteers are welcome and waterfront landowners can erect their own nest boxes following the specifications provide at www.georgiabasin.ca/puma.htm.