Purple Martin population growing in B.C.

The Ladysmith Harbour has one of the largest active Purple Martin colonies in B.C.

The Western Purple Martin Foundation hosted its eighth annual Purple Martin Open House July 29 at the Ladysmith Maritime Society Community Marina. Here

The Western Purple Martin Foundation hosted its eighth annual Purple Martin Open House July 29 at the Ladysmith Maritime Society Community Marina. Here

The Purple Martin colony at the Ladysmith Harbour is one of the largest active colonies in B.C.

There were 65 active nests In 2011, and so far this year, the Georgia Basin Ecological Assessment and Restoration Society (GBEARS) has found close to 60 pairs of birds in the harbour and hasn’t even completed a full nest check.

This good news was shared during the Western Purple Martin Foundation’s Purple Martin Open House July 29 at the Ladysmith Maritime Society Community Marina.

The Purple Martin is the largest swallow in North America, and the bird’s population in B.C. has been in decline for a century or more due to habitat loss from logging, agricultural land clearing, fire suppression, urban development and competition for nest cavities with European Starlings and House Sparrows.

Their population has increased steadily with the use of nest boxes. The B.C. nest box program started in the mid-1980s at Cowichan Bay Estuary,and the program is now called the B.C. Purple Martin Stewardship and Recovery Program.

In the last 20 years, about 1,500 nest boxes have been distributed among 90 marine and freshwater sites throughout the Purple Martins’ historical breeding range, which includes southern and eastern Vancouver Island, the Sunshine Coast, the Lower Mainland and the Gulf Islands, and more than half of those nest boxes have been distributed since 2000.

According to GBEARS, there were only 510 breeding pairs of Purple Martins in B.C. in 1985. In 2011, there were about 750 breeding  pairs across the province.

The long-term challenge as the population grows is to re-introduce the species to its historic nesting habitat in the wild so that the birds are less dependent on humans.

“In the wild, martins used to nest in woodpecker cavities, so there might only be three to six cavities in an area, so nesting areas would be very small in the natural habitat, but we don’t have as many old trees and snags in the forest anymore, so we don’t see martins in the wild anymore,” said Charlene Lee, project co-ordinator for the recovery program.

An important part of the B.C. Purple Martin Stewardship and Recovery Program is banding nestlings. Coloured bands represent different year classes and locations, and each band has a unique number that can be read through a spotting scope. By reading bands, program staff and volunteers can get an idea of how birds move between colonies, which age groups show up when, and how many birds are surviving each year.

Birds banded in Ladysmith have dispersed as far as Campbell River, Sooke and the San Juan Islands, explained Lee.

Lee says the purpose of the Purple Martin Open House is mainly education for young and old.

“It’s nice to have children come so they can see baby birds being banded and get an appreciation for nature, and it’s a good-news story, and we’d like to spread the good news,” she said. “People can find out some of the reasons behind why the nest boxes are here. Without nest boxes, purple martins would likely not exist in B.C. anymore.”