Data collection as part of the Deepwater Horizion Carcass Drift Study (Bird Study #1D) occurred during July and August, 2011. Data were collected by R.G. Ford Consulting Company (RGFCC) and Biodiversity Research Institute (BRI), under contract to the U.S. Fish and Wildlife Service, and CardnoENTRIX personnel, under contract to the Responsible Party. There were two main objectives: to quantify the length of time study carcasses float prior to sinking, and quantify the proportion of study carcasses that do not sink and eventually become beached or stranded within the area searched for bird carcasses during the Deepwater Horizon Oil Spill. Bird carcasses and dummies were dropped from boats and helicopters during July, 2011. Data collected on the deployment of each carcass and dummy are found in the Drift Deployments dataset. After deployment, drifters were tracked by aerial, boat, and ground teams. Data collected on sightings of the drifters are captured in this Drifter Sightings dataset. As drifters were tracked via radio telemetry, teams from planes surveying the area recorded sightings of a carcass or dummy by recording waypoints directly into GPS units. Boat and ground crews recorded information on sightings and the collection of drifters along the shoreline into field datasheets (either a “Drifter Sightings Datasheet” or “Bird Search Effort and Birds Collected Data Form”), and by taking photographs. Study photographs include sightings of carcasses and dummies, the collection of drifters, and photographs of field datasheets. Additional details on Bird Study #1D field efforts and results are provided in the work plan and End of Study Report (Draft Final End of Study Report Using Radio Telemetry to Determine the Fates of Bird Carcasses Drifting in the Northern Gulf of Mexico (Carcass Drift Study - Bird Study #1D), RGFCC 2/24/2014).