The objective of the Deepwater Horizon Work Plan for the Beach Searcher Efficiency Study (Bird Study #1B) was to estimate the detection probability of carcasses, or the efficiency of wildlife search teams across beach habitats of the northern Gulf of Mexico. This study complemented work done under Bird Study #1C and Bird Study #19, which estimated carcass persistence on beach habitats and searcher efficiency and carcass persistence in marsh habitats of the northern Gulf of Mexico, respectively. The data collected under this work plan were used by the Trustees to help quantify spill-related avian mortality using a Shoreline Deposition Model (SDM). In order to accurately quantify avian injuries the SDM accounts for the number of carcasses missed by observers (searcher efficiency) as well as carcass losses to scavenging and other natural processes (carcass persistence). Data collection for Bird Study #1B was conducted in late Summer 2010 while some of the wildlife search teams were still conducting beached bird surveys. Study teams placed marked, unoiled carcasses along beach transects and recorded how many carcasses were found by search teams. Additional information on the study procedures and data are provided in the end of study report (Detection Probability (Searcher Efficiency) Study Bird Study #1 B End-of-Study Report, July 28, 2013).