<span>The first part of the question is: The male's ability to shake its tail is the mechanistic cause of this behaviour. For the second part of the question, the mate choice is the adaptive function of this behaviour.</span>
A weather radar is an instrument that is used to locate precipitation, calculate its motion and determine the type i.e hail, snow or rain. It sends electromagnetic energy pulse into the atmosphere. If that pulse of energy interacts with something, then it reflects back the energy, which can be sensed by the weather radar.
Nowadays, most radar used are Doppler effect, which has dual polarization, it determines that movement is toward or away from the radar.