This dataset includes XY coordinates and species and behavioral observations of birds detected in aerial imagery captured over coastal islands along Maine's coast during 30 May. - 3 June 2019. The Partenavia P.68 Observer plane flew over 268 islands within the Gulf of Maine (GOM). The plane flew at an altitude of 310 m above ground level and was equipped with a PhaseOne iXU-RS1000 (100 megapixel) multispectral camera and 70 mm lens to capture 4-band (red, green, blue, (RGB) and near-infrared (NIR) light) imagery with a ground sampling distance of 2 cm/px. Timing for the aerial image collection was selected to reflect peak nesting periods for the focal species (Herring Gull, HERG; Great Black-backed Gull, GBBG; Double-crested Cormorant, DCCO; Common Eider, COEI; and terns, Tern spp.), during which one parent is typically present on the nest. Imagery was captured during daylight in clear weather (i.e., no rain or high winds) for ten separate surveys beginning at different times and with various flight path extents. Although the target was colonial nesting seabirds, any birds that could be identified were noted in the dataset. All images were orthorectified, georeferenced, and mosaicked into images spanning one or more islands. Three observers reviewed the images, identified detected birds to species and behavior, and reconciled any differences. The dataset includes the detections recorded by each observer and the reconciled species and behavior identification. Summaries of the methods and final counts are presented in two theses: Kline, Logan R. 2022. Characteristics contributing to uncertainty in image-based artificial intelligence classifications of colonial nesting birds. M.S. Thesis, Ecology and Environmental Sciences, University of Maine, Orono. 118 pp. Lewis, Meredith A. 2022. A bird's eye view: observer uncertainty in aerial image counts of colonial seabirds and an assessment of the status of coastal island gull and cormorant populations. M.S. Thesis, Ecology and Environmental Sciences, University of Maine, Orono. 113 pp.