Various methods of obtaining population data are being evaluated to select the best method for estimating population sizes of ground-nesting waterbirds at the Anaho Island National Wildlife Refuge. These colonial nesting birds are sensitive to human disturbance and will abandon their nests if appropriate methods are not utilized during population surveys. Unmanned aircraft systems (UAS) are proving to be a useful alternative to land-based and/or manned aircraft visual surveys and have the potential to be a more economical, less obtrusive, safer, more efficient, and versatile means to survey waterfowl population numbers. Utilizing low-cost cameras onboard the UAS enable the biologist to collect high-resolution color and infrared images. Processing the data to create three-dimensional models using structure-from-motion photogrammetric software, along with automated feature extraction techniques, is proving to be an effective method of collecting the data.
Natural color imagery collected via the RQ-11A Raven UAS platform. Three-dimensional models created from the individual images captured by the UAS. Red pins mark individual American pelicans on the island.