New methods for assessing Marbled Murrelet nesting habitat: Air photo interpretation and low-level aerial surveys

Abstract

This extension note summarizes the application of two new methods that were developed to assess the quality of forest habit that Marbled Murrelets (Brachyramphus marmoratus) use for nesting in British Columbia: air photo interpretation and low-level aerial surveys. Both methods use comparable sixlevel ranking systems that are based on the availability of forest attributes deemed important for nesting murrelets. The methods were developed and refined through preliminary work done in many varied coastal regions in British Columbia; they were designed to complement each other and be applicable to either small patches (1-2 ha) or to larger polygons used in mapping for forest management. Both methods were tested in comparisons with known murrelet nest sites and both are currently being applied by government and forest industry biologists. This note provides practitioners who are proposing to use one or both of these methods a concise guide to their suitability and limitations, and also provides links to relevant reports that offer greater detail on testing and applicability.