This dataset contains gps tracking and accelerometer data of 18 adult lesser black-backed gulls on Texel (the Netherlands) during their breeding season, using UvA-BiTS tags [1]. The gps data is enriched with with behaviour and weather data.The behaviour has been predicted by a classification model using accelerometer data (the approach is detailed in [2]). The weather data is derived from the ERA-Interim dataset [3] by interpolating towards the gps-points. The data fall in the time-window May 15 00:00:00 until June 15 00:00:00 of the years 2012, 2013 and 2014 (i.e. within the breeding season for this population). The data have a resolution of 5 minutes, but data coverage over the time-window is incomplete (the set does not contain a record at every 5-minute interval over the time-window) because at some instances either accelerometer or weather data were not available. The data set comprises a collection of five different file types: 1. gps data (gps.zip); 2. accelerometer data (acc.zip); 3. expert labelled ...