Grace is part of the invasive pest plant control team - which means she spends some of her free time up in the sanctuary pulling up the weeds that threaten to suffocate the native bush on which the birdlife depends. The team meets for working bees fortnightly on Saturdays, and Grace has just brought together a group of people like herself who still want to help pulling out the weeds, but who "aren't getting any younger".
She started out volunteering in the visitor centre then joined the weeding team: "But now I find it too steep to get up into some areas. There are places lower down that still needs work. So I thought, I will try to get people interested in weeding there, at their own pace, working away in their own time on allocated areas."
Like any social entrepreneur worth their salt, she's making sure people have the means to do it themselves: "Volunteers can come when they like knowing they are part of a group effort," she says.
"It's different to garden weeding - the terrain is different, the tracks are narrow. You've got to prioritize, and pull out the weeds that are the most destructive, old man's beard, climbing asparagus, banana passion vine. If you let them go they'd cover the canopy so stopping that is our highest priority."
The work brings its own rewards: "I left teaching as I was burned out, and discovered gardening was really restorative. I lost two people who were close to me in quick succession. Gardening helped. There is something about having your hands in the soil that restores you. I love the Brook, I think the river up there is magical. One of my most recent joys was seeing the flowering rata for the first time."
Grace says the main quality you need to join the weeding team is being comfortable in the native bush. "You need to know your weeds and you need to know your natives. People who are familiar with the New Zealand bush - trampers are good, because if you're a tramper you're comfortable on bush tracks."
Raeonie Ellery is an office administrator and volunteer coordinator at Brook Sanctuary: "Now we're getting closer to getting the funding for the fence we need fit strong people to help with invasive plant control and track cutting," she says.
"We have all sorts of roles for all sorts of skill sets and fitness levels - from people on the frontlines staffing our visitor centre and volunteering in the public events team, to bird monitoring and track cutting. Some of our tasks involve health and safety so we only take on people over the age of 18, and we provide full training."
She says It's a chance to learn new skills and see a side of our sanctuary that few people get to see. "Everyone gets something out of it, and we're all here for the same reason - to make a difference for nature."
You can find out more about volunteering at Brook Sanctuary at: www.brooksanctuary.org or contact Raeonie at: raeonie.ellery@brooksanctuary.org.
Or find a conservation group near you supported by WWF and The Tindall Foundation and run by volunteers at: www.wwf.org.nz/what_we_do/community_funding/.
This article is published as a partnership between WWF and Element. Like what you see? Sign up to our newsletter. We're also on Facebook and Twitter.