The Bring Back the Bluebirds project, which began in 2012, involves moving up to 10 pairs of Western bluebirds from southern Washington state to Vancouver Island every year.
The birds are held in an outdoor aviary for several weeks before they're released as breeding pairs. After that, the organization tracks their nesting success.
"They don't always stick, but we're seeing an increase in the percent of bluebirds we released actually staying where we released them to nest," project co-ordinator Jemma Green told On The Island.
"We're seeing an increase in the number of birds returning on their own every spring from year to year and we're also seeing an increase in the number of nests these birds have and the number of young."
There are now 19 returned Western bluebirds in the Cowichan Valley, including six breeding pairs, according to the Garry Oak Ecosystems Recovery Team Society.
A total of 16 eggs and 15 baby birds have also been tracked this spring.
Green says bluebirds are a crucial part of the Garry oak tree ecosystem, where more than 115 species are listed as at-risk provincially and federally.
"So if we can bring bluebirds back and restore those habitat elements that they need to thrive, we're restoring a good part of that ecosystem and hopefully benefiting a whole bunch of species at risk as well."
To hear the full interview with Jemma Green, listen to the audio labelled: Western bluebirds returning to Vancouver Island