Despite their suggestive name, male Purple Martin adults have iridescent blue-black feathers that radiate a purple sheen in the right light. Female Purple Martins are grey-brown and have speckled or striped undersides. Purple Martins are social birds with massive nesting and roosting colonies. At the end of their breeding season, they put on a spectacular show of migratory roosting at sunset, involving flocks of tens or hundreds of thousands of swarming birds.
A Purple Martin roost in Round Rock, Texas in August 2020.
Purple Martins winter in South America, typically Brazil, and migrate to North America to breed in the spring. Canada represents the northernmost limit of the birds’ migration range. There are three known subspecies of Purple Martins: eastern Progne subis subis, desert southwest Progne subis hesperia, and west coast Progne subis arboricola.
Purple Martins, the largest swallow in North America, are uniquely urbanized birds closely tied to human presence.
Of the three subspecies, two are known to regularly nest in human-made structures. The eastern subspecies nests almost entirely in human-made housing structures, and the west coast subspecies nests in human-made nest boxes as well as natural tree cavities in some areas. In other words, most Purple Martins don’t breed in wild spaces—they rely on human-made structures to reproduce.
Ornithologists believe human-made Purple Martin housing emerged centuries ago from practices by the Choctaw and Chickasaw tribes within the modern jurisdiction of Alabama. The tribes hung hollowed-out gourds, adding entrance holes that resemble natural cavities on tree branches to attract Purple Martins. It is thought that this was a natural method of insect and/or mosquito control around village sites (Purple Martins are aerial insectivores). Settlers caught on to the technique and assembled their own gourds. The practice has since become widespread, with conservation organizations, grassroots initiatives, and individuals across North America creating homes for Purple Martins.
There was a time when humans put Purple Martins in direct danger. These troubles date back to the 19th century, when European Starlings and House Sparrows were introduced to the United States. The invasive birds out-competed Purple Martins for natural breeding cavities. The Purple Martin population has since rebounded.
Today, Purple Martins are considered stable by The International Union for Conservation of Nature’s Red List, but their numbers are still dropping around the world and wildlife experts are researching potential stressors. A 2014 study based in Wisconsin found that the Purple Martin population decreased by 6% annually.
Purple Martins were almost extirpated (locally extinct) in British Columbia by the 1980s, but the species has since recovered. Today, the population is thought to be increasing annually in BC.
However, Purple Martins are blue-listed (a species of special concern) in BC. Since the regional recovery of Purple Martins, they have nested exclusively in nest boxes, so their presence in the province is entirely dependent on human-made housing.
The revitalization of Purple Martins across BC wouldn’t be possible without grassroots conservation efforts. Kiyoshi Takahashi, for instance, started building nest boxes in 1985 in Port Moody. He’s since built 85 nest boxes and is considered a major asset to regional Purple Martin conservation efforts, according to the Wildlife Rescue Association of BC. Today, there are Purple Martin nest boxes across southern BC, on the mainland, and on Vancouver Island.
Nest box programs at Maplewood Flats (North Vancouver) and Rocky Point (Port Moody) initiated in the 1990s greatly contributed to the resurgence of Purple Martins in BC. Now, around 110 nest boxes are mounted every spring upon the return of the Purple Martins at Maplewood Flats. In 2019 it was estimated that there was nesting activity in around 86 nest boxes at the Maplewood Flats colony.
As part of our commitment to redress and reconciliation, Wild Bird Trust acknowledges that its conservation and restoration programs such as the Purple Martin (PUMA) Nest Box program have been carried out with little to no consultation or involvement of the Tsleil-Waututh Nation, the original and continuous stewards and keepers of this land. The board of directors and management are dedicated to ensuring the involvement of the Tsleil-Waututh community broadly, including the PUMA program moving forward.