The Audubon Core metadata schema ("AC") is a representation-neutral metadata vocabulary for describing biodiversity-related multimedia resources and collections. Multimedia Resources are digital or physical artifacts which normally comprise more than text. These include pictures, artwork, drawings, photographs, sound, video, animations, presentation materials, interactive online media including identification tool packages involving text and other media. A multimedia collection is an assemblage of such objects whether curated or not and whether electronically accessible or not. For the purposes of this schema we regard a collection of multimedia resources itself as a 'multimedia resource'. Multimedia descriptions are digital records that document underlying multimedia resources. Audubon Core is focused on biodiversity-related multimedia resources. It shares terminology and concerns with many well known and important standards for describing access to resources such as Dublin Core(DC), Darwin Core (DwC), the Adobe Extensible Metadata Platform (XMP), the International Press and Telecommunications Council (IPTC) the Metadata Working Group (MWG) schema, the Natural Collections Schema (NCD), and others. Where there is an exact match to concerns of such standards, Audubon Core adopts their identifiers and definitions. Audubon Core particularly intends to ease the burden of holders of descriptions specified either by DwC or DC by allowing use of those existing descriptions where appropriate.