Northern harrier, male (2 of 3)

This male would puff up his throat, stretch out his neck, raise his head straight up, with a bobbing motion, and let out a cough, or perhaps it was a call. It may be a way to induce regurgitation, but I saw this individual do it on many occasions and I never saw him produce a pellet. If anyone could shed some light on this behaviour, I'd be happy to know.

Done