This metadata document describes the data contained in the "rawData" folder of this data package. This data package contains all data collected by the Argos System from 6 satellite transmitters attached to Glaucous-winged gulls on Middleton Island and 42 Argos-linked GPS satellite transmitters attached to three species of large-bodied gulls (genus Larus) and hybrids thereof, captured at landfills in southcentral, western and northern Alaska. The transmitters carried GPS receivers, so GPS tracking data represent the backbone of this data release. However, because the GPS locations were communicated through the Argos System, a time series of Argos (Doppler) tracking data also exists and is included. Five data files are included in the "rawData" folder of this data package. Two data files (with identical content) contain the raw Argos DIAG (Diagnostic) data, one in the legacy verbose ASCII format and one in a tabular Comma Separate Value (CSV) format. Two other data files (with identical content) contain the raw Argos DS (Dispose) data, one in the legacy verbose ASCII format and one in a tabular CSV format. The fifth file, "deploymentAttributes", contains one record for each transmitter deployment in a CSV formatted table. The deployment attributes file contains information such as when the transmitter was attached to the animal, when tracking of a live animal ended, and a variety of variables describing the animal and transmitter. This table is identical to the "deploymentAttributes" table in the "processedData" folder of this data package.