Hønsefuglportalen is developed to make tetraonid line transect surveys and data entry directly to the server easier and less error-prone. Users that are registered in Hønsefuglportalen will get access to their survey lines when they log in with the mobile app. When they start their line transect surveys, the correct transect line is selected and the survey can be initiated. While surveying, the mobile app will directly keep track of duration, distance to the transect line, and total distance surveyed. When an observation of a tetraonid bird, the observation can easily be registered. Species and number of birds in the cluster is registered manually, whereas time, GPS location and perpendicular distance to transect line is registered automatically. When the transect survey is completed, all data including the track log will be stored locally on the phone and transferred to Hønsefuglportalen when the user is online.