Dusky Canada geese (Branta canadensis occidentalis) comprise one of the smallest populations of geese in North America and their breeding range is limited to Prince William Sound, primarily the Copper River Delta, and Middleton Island, Alaska. The Alaska Region of Migratory Bird Management initiated an aerial breeding pair survey on the Copper River Delta in 1986 after reported declines in the abundance of dusky Canada geese on their nesting and wintering grounds. Since 2008, the Pacific Flyway Council uses results of the aerial breeding pair survey, together with Middleton Island ground counts conducted by the Alaska Department of Fish and Game, as a management index to determine optimal hunting regulations. Survey objectives are to (1) produce a reliable breeding population index to determine an annual harvest strategy, and (2) document changes in the distribution of nesting birds. In addition to dusky Canada geese, trumpeter swans (Cygnus buccinator) are also recorded.Aerial track files collected using the FWS software program “RECORD” (John I. Hodges, MBM-Alaska) running on laptop computers. Program RECORD was activated during the survey before arriving at the first transect and shut down after the last transect was completed, prior to engine shut-down. “Raw” track files recorded the flightpath of the aircraft including the area surveyed on each transect. GPS coordinates were captured every five seconds using a recreational grade receiver with an estimated positional accuracy of 5-10 meters after the software program was activated. These raw track files have not been quality checked, so they may contain missing or erroneous coordinates if the GPS signal was intermittent or weak.Raw track files have not been quality checked and may contain missing or erroneous coordinates.
