Surveys of Resting and Migrating Birds
To assess the impact of a project on migrating and resting birds, we conduct appropriate population surveys during the spring and autumn migration and during the winter months. Regular observations in one or two weekly intervals are common and are made from protected viewpoints using a spotting scope (30–60× magnification). The bird migration should be recorded from September to November and March to May. Moving the period back by 2–3 weeks may be useful in certain regions. The resting birds are usually recorded in winter, between December and March. Adjustments may also be necessary here. A combination of resting and migratory bird studies is generally possible. During migratory bird surveys the species, number, direction of migration and especially the altitudes of migratory individuals are recorded. During the resting bird observations the flight paths of sleeping to foraging sites and frequency of flights of certain species (ducks, geese, swans) over the project area per day are determined. In the case of expected water bird concentrations we recommend to choose a larger investigation radius to obtain cross findings such as location of the sleeping sites, alternative food area, etc.
