Volunteers had also provided support at the Valley Project’s premises on Saturday morning.
About 50 people had attended a rat trap-making session on Saturday morning, and in the afternoon about 20 others had gone to an awareness-raising gathering about using a modern possum trap, Miss Cross said.
North East Valley School pupil Ernest Billot said he was enjoying the hammering and other aspects of making the wooden traps.
The Valley Project, the University of Otago, Orokonui Ecosanctuary and Open VUE supported the backyard programme, which aimed to "encourage ecological action in backyards in the Lindsay Creek catchment", including in North East Valley, Miss Cross said.
After the successful development of Orokonui Ecosanctuary in 2007, the Valley Project, Open VUE and other supporters were keen to create a green corridor, including in the valley, to encourage native birds such as kaka, which were breeding at Orokonui, to move into the wider Dunedin area, she said.
It was hoped more native plants would be added to backyards and predator numbers would be cut.
Open VUE had been launched in 2017. It had earlier worked closely with schools, and was now working to promote a network of backyard ecosanctuaries.
"I’m very happy about how the day went — obviously, delighted about the number of people who came along," she said.
The hope was to have 100 families signed up to take part in the valley initiative before the end of the year.
Covid-19 had pushed matters back a little bit, but "I think we’re on track for that [the participation target], given how successful it was today", she added.