Mass Audubon has purchased the Spring Street Woodlands in Marshfield, adding the 31-acre parcel to the North River Wildlife Sanctuary. The sale closed on March 15 and the informal trails on the land are now open to the public. The conservation group raised approximately $171,500 to cover the purchase price, appraisal, and legal expenses. “Lots of people in the local community assisted with this, which was fabulous,” said Sue MacCallum, director of the group’s South Shore Sanctuaries. Mainly woodland, the property contains the headwaters of Hannah Eames Brook and is home to a variety of wildlife. The land was previously owned by a private realty trust controlled by the Hale family, which bought it in the 1940s, according to trustee Peter Hale.