In 1985, a census was conducted of the western purple martin, an eye-catching swallow.
Biologists checked usual haunts, looking for nests in snags in the forest and pilings on the waterfront.
After an exhaustive search, the enumeration counted precisely five breeding pairs. Ten birds. You could count them on the fingers of both hands.
Those five pairs flew away that fall, as was custom, leaving their human admirers on Vancouver Island to launch a desperate campaign to preserve the presence of the subspecies here.
Their efforts have paid off. The perilous decline was reversed and, after years of slow growth, the bird population has rebounded. More than 750 nesting pairs have been counted in British Columbia this season.
On Sunday, the Western Purple Martin Foundation held their eighth annual open house at the marina in Ladysmith, site of the largest colony in the province. Visitors were asked to wear purple to mimic the dark, glossy, blue-black plumage of the adult male.
Hatchlings were taken from nests to have placed on their scaly legs electronic bands, which will give scientists useful information about the birds, their health and their migration.
The birds are appealing both for the notable colour of the adult males, as well as for a “cheerful, chortling call,” said Charlene Lee, a retired biological consultant and president of the Georgia Basin Ecological Assessment and Restoration Society, a conservation group. “It seems to appeal to people.”
Those who have fought to preserve the presence of Progne subis arboricola on the island spend a few anxious weeks each spring awaiting the return of the birds from a seasonal migration from sunnier climes. It is a hands-on assignment.
“It’s almost like we’ve got adopted children,” Ms. Lee said. “You see them come back. You handle them to see how they’re doing. You put leg bands on them. You send them off in the fall. Then, you hope they’re doing well down in South America. When they’re about to come back and you wonder, ‘Are we going to have a good return?’ You’re always anxious to see how well they’ve done.”
The birds returned in mid-April, as expected, only to face a dearth of food owing to the wet weather. Martins are aerial insectivores, dining on moths, beetles, flying ants and dragonflies, a preferred treat. The rains reduced the population of flying insects. In turn, the birds laid only three or four eggs per nest, instead of the five or six eggs of previous years.
The population’s precipitous decline came about in part because of a shortage of suitable nesting places. The martins are finicky about where they live, preferring natural cavities and woodpecker holes. The logging of forests meant fewer snags left standing. Replanted trees grow at similar heights, while the martins prefer to be above the canopy, farther from ground predators and the better to spot airborne ones.
Meanwhile, on the waterfront, it became common to replace old pilings with ones coated in creosote.
A year after the census counted five breeding pairs, volunteers began placing nest boxes in such locations as Victoria Harbour and Cowichan Bay. A decade later, a census counted 55 pairs. The number has grown every year since.
Naturalist groups have now placed 1,600 nest boxes for the martins at 70 marine and 20 freshwater sites in the province. These boxes are modest affairs, as the western purple martins eschew the elaborate, apartment-style boxes used to house their eastern cousins.
When the weather turns, the martins will fly south to winter in southeastern Brazil.
Since those 10 birds were counted all those years ago, you might say the western purple martin has changed colours. The bird has moved from the province’s Red List as an endangered subspecies to the Blue List, meaning it is merely vulnerable.