An avian detection system for determining risks of collision between a collision object and bird objects includes avian radar system(s) providing a first type of information data relating to objects detected, and a transponder receiver receiving transponder data transmitted or broadcasted by transponders provided at the collision objects. Processors are configured to receive first type of information data corresponding to the detected objects and provide radar plots. The processors are further configured to receive the transponder data and provide transponder plots, to create and store a number of object tracks based on the provided radar plots and transponder plots, with each track holding object data corresponding to or determined from data of matching plots, and to determine one or more risks of collision or collision risk levels for the collision object based on object data of a plurality of the obtained object tracks.