Update on the Intercontinental Traveller – the Purple Martin

Published by Michael Dunn on 04/27/2026 05/06/2026

Photo of a purple martin with dragonfly by Andrew A. Reding.

In 2005, the B.C. Purple Martin Stewardship and Recovery Program (PUMA) oversaw the installation of two sets  of nesting boxes here on SḴŦAḴ | Mayne Island: ten boxes in Bennett Bay beside the Mayne Island Resort pier, and another ten in Miners Bay. The boxes attracted their first occupants in the summer of 2006. Parks Canada supported the new project by supplying a boat to access the boxes for banding birds, and to remove them for cleaning, and our local Trust Committee provided funding for several project accessories. We thought it would be good to see how these birds are doing 21 years later.

Getting to Know Purple Martins

Purple Martins are the largest swallow in North America. The western subspecies (Progne subis arboricola) occurs from southwest B.C. to southern California. It is separate and genetically distinct from the eastern subspecies, P. subis subis. These birds undertake a long migration every year in September. They leave their breeding sites in the Salish Sea and move down the west coast of North America through Central America to spend their winters in the Amazon Basin or the Atlantic coast of Brazil. They begin their return flight in March and are in Oregon by early April, and to the Salish Sea in mid to late April. As I write this on April 20^th, the first male martins have been heard over Miners Bay.

Martin Population Decline

The western purple martins are Blue-listed (a species of concern provincially) and vulnerable in British Columbia, and are still recovering from a severe population decline in the mid-to-late 1900s. Historically, martins nested in woodpecker cavities in old trees or snags. They prefer open woodlands or areas near water. Intensive timber harvest, fire suppression, and snag removal coupled with agricultural clearing and urbanization reduced this preferred habitat type within their original breeding range of the coastal lowlands of the Georgia Basin. In addition, populations of non-native European Starlings and House Sparrows became established in B.C. in the early-to-mid 1900s. These non-native birds compete with martins for nest cavities.

As other suitable habitat was lost, martins shifted to cavity nesting in the decaying, untreated, wooden pilings from industrial development that were then abundant around the Salish Sea. These pilings later became limited in supply, as many rotted and fell, or were replaced by treated pilings and later by steel and concrete. By the early 1980s, when old untreated pilings were almost entirely gone, the B.C. population of western purple martins was reduced to less than ten known breeding pairs.

What Has Been Done to Help?

To prevent extirpation (localized elimination) of this species in B.C., a volunteer-based nest box program was launched around the Salish Sea in 1986 (an earlier program had been launched in Puget Sound). The premise of this program was simple: design and provide suitable nesting habitat that mimics woodpecker cavities. The logical placement of these boxes was to use existing marine pilings and dock structures around the shorelines. Incredibly, the martins took to these boxes, and by 2002 the B.C. population had risen to 200 pairs and by 2018 to 1200 pairs.

To date, the purple martin program has installed more than 1500 nest boxes near or over water representing 120 colonies.

SḴŦAḴ | Mayne Island nest boxes had 100% occupancy in the first year. Occupancy rates have remained high since, but with some fluctuations (ranging from 70% to 100%) over the twenty years. Weather conditions, starlings, and house sparrows all have had effects on the population levels over time. In 2025, the Miners Bay dock was upgraded, and many old pilings were replaced with steel piles. The original nest boxes were taken down and new ones installed for the 2026 season. As adult birds usually come back to the same nest site every year, it is hoped that they will take to the new boxes and locations.

The nesting success and fledgling production of purple martins is highly sensitive to adverse (wet) weather-induced reduction in food supply, and yearling (sub-adult) recruitment and population growth or decline are highly dependent on reproductive success. Poor weather, particularly in May and June, reduces the food supply (flying insects) which affects the number of healthy chicks that can be raised to fledglings. Those fledged chicks then must then complete the fall migration to the Amazon Basin, which is 11,000 km one way, or 300-400 km per day. The survival of chicks on migration is only 40-60%.

How Are Martins Doing Now?

The use of the nest boxes has allowed the local martin population to grow, and Purple Martins have become welcomed spring and summer residents on SḴŦAḴ | Mayne Island. In the Salish Sea region, the population has grown from five breeding pairs in 1985 to an estimated 1200 pairs today–truly a success story. We must thank all the volunteer stewards who cared for and monitored these boxes over the decades the program has been running.  The adult males have begun to arrive back to their breeding sites on the island, and this year we hope for many returning adult birds, good weather, and abundant food to ensure healthy numbers of chicks.

Where Can I See Purple Martins on Mayne Island?

Head down to the either the Miners Bay dock or to Bennett Bay near the Bennett Bay Resort pier, and you will see the iridescent purple-black male martins with long, tapered wings and short, slightly forked tails, sitting on, or soaring near, the nest boxes on the pilings. Females and young birds are duller, with dark, grayish-brown upperparts and pale, grayish-white breasts and bellies. You can also hear and experience the glorious songs of these birds from now until August. It will make your day.

Sources:

Cousens,N. B. F. and J.C. Lee, 2012. Status Report on the Western Purple Martin (Progne subis arboricola) in British Columbia. Prepared for BC Ministry of Environment, Victoria, BC.

Rochet, H. 2018. The Purple Martins of Mayne Island, BC. Article for Mayne Island Conservancy Newsletter

Gibson, N. 2021. Mayne Island’s Purple Martins. Article for Mayne Island Conservancy Oystercatcher.

Enright, Don email April 9, 2026. Summary Data on Purple Martin nest boxes for 2019 to 2025 at Miners Bay and Bennett Bay, Mayne Island.

Atlas of the Breeding Birds of B.C.